PHP
PHP is a server scripting language, and is a
powerful tool for making dynamic and interactive Web pages quickly.
PHP scripts are executed on the server.
What is PHP?
- PHP
is an acronym for "PHP Hypertext Preprocessor"
- PHP
is a widely-used, open source scripting language
- PHP
scripts are executed on the server
- PHP
costs nothing, it is free to download and use
What is a PHP File?
- PHP
files can contain text, HTML, CSS, JavaScript, and PHP code
- PHP
code are executed on the server, and the result is returned to the browser
as plain HTML
What Can PHP Do?
PHP can generate dynamic page content
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PHP can collect form data
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PHP can send and receive cookies
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PHP can encrypt data
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PHP can add, delete, modify data in your database
|
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PHP can create, open, read, write, and close files on the
server
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||
PHP can restrict users to access some pages on your
website
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With PHP you are not limited to output HTML. You
can output images, PDF files, and even Flash movies. You can also output any
text, such as XHTML and XML.
Why PHP?
- PHP
runs on various platforms (Windows, Linux, Unix, Mac OS X, etc.)
- PHP
is compatible with almost all servers used today (Apache, IIS, etc.)
- PHP
supports a wide range of databases
- PHP
is free. Download it from the official PHP resource: www.php.net
- PHP
is easy to learn and runs efficiently on the server side
PHP 5 Installation
What Do I Need?
To start using PHP, you can:
Find a web host with PHP and MySQL
support Install a web server on your own PC, and then
install PHP and MySQL
Use a Web Host With PHP
Support
If your server has activated support for PHP you
do not need to do anything. Just create some .php files, place them in your web
directory, and the server will automatically parse them for you. You do not
need to compile anything or install any extra tools. Because PHP is free, most
web hosts offer PHP support.
Set Up PHP on Your Own PC
install a web
server - install
PHP - install a database,
such as MySQL
The official PHP website (PHP.net) has installation
instructions for PHP: http://php.net/manual/en/install.php
To get PHP up and running immediately for
Windows, you can: Download WebMatrix
PHP
5 Syntax: The PHP script is executed on the server, and the
plain HTML result is sent back to the browser.
Basic PHP Syntax A PHP
script can be placed anywhere in the document.
The default file extension for PHP files is
".php". Built-in PHP function "echo" to output the text
"Hello World!" on a web page:
Note: PHP statements are terminated by semicolon (;). The closing
tag of a block of PHP code also automatically implies a semicolon (so you do
not have to have a semicolon terminating the last line of a PHP block).
Comments in PHP
// for one
line /*
for many comment lines */
PHP Case
Sensitivity: all user-defined
functions, classes, and keywords (e.g. if, else, while, echo, etc.) are
case-insensitive. But all variables are case-sensitive.
PHP
5 Variables
- A
variable starts with the $ sign, followed by the name of the variable
- A
variable name must start with a letter or the underscore character
- A
variable name can only contain alpha-numeric characters and underscores
(A-z, 0-9, and _ )
- Variable
names are case sensitive ($y and $Y are two different variables)
Creating (Declaring) PHP
Variables
PHP has no command for declaring a variable. A
variable is created the moment you first assign a value to it:
PHP is a Loosely Type Language
PHP automatically converts the variable to the
correct data type, depending on its value.
PHP Variables Scope
PHP has three different variable scopes:
Local - global - static
Local and Global Scope
A variable declared outside a
function has a GLOBAL SCOPE and can only be accessed outside a
function.
A variable declared within a
function has a LOCAL SCOPE and can only be accessed within
that function.
You can have local variables
with the same name in different functions, because local variables are only
recognized by the function in which they are declared.
PHP The global Keyword
The global keyword is used to access a global
variable from within a function.
To do this, use the global keyword before the
variables (inside the function):
<?php
$x=5;
$y=10;
function myTest()
{
global $x,$y;
$y=$x+$y;
}
myTest(); // run function
echo $y; // output the new value for variable $y
?>
$x=5;
$y=10;
function myTest()
{
global $x,$y;
$y=$x+$y;
}
myTest(); // run function
echo $y; // output the new value for variable $y
?>
PHP also stores all global variables in an array
called $GLOBALS[index]. The index holds the name of the
variable. This array is also accessible from within functions and can be used
to update global variables directly.
<?php
$x=5;
$y=10;
function myTest()
{
$GLOBALS['y']=$GLOBALS['x']+$GLOBALS['y'];
}
myTest();
echo $y; // outputs 15
?>
$x=5;
$y=10;
function myTest()
{
$GLOBALS['y']=$GLOBALS['x']+$GLOBALS['y'];
}
myTest();
echo $y; // outputs 15
?>
PHP The static Keyword: Normally, when a function is executed, all of its variables are
deleted, but sometimes we want a local variable NOT to be deleted. We need it for a further job. To do this, use the static keyword when you first declare the variable:
<?php
function myTest()
{
static $x=0;
echo $x;
$x++;
}
myTest();
echo "<br>";
myTest();
echo "<br>";
myTest();
?> Then, each time the function is
called, that variable will still have the information it contained from the
last time the function was called. Note: The variable is still
local to the function.
PHP
5 echo and print Statements: In PHP there is two basic ways to get
output: echo and print.
- echo
- can output one or more strings
- print - can only output
one string, and returns always 1
Tip: echo is marginally faster compared to print as echo does not
return any value.
The PHP echo
Statement echo is a language
construct, and can be used with or without parentheses: echo or echo().
Display Variables
The following example shows how to display
strings and variables with the echo command:
<?php
$txt1="Learn PHP";
$txt2="W3Schools.com";
$cars=array("Volvo","BMW","Toyota");
echo $txt1;
echo "<br>";
echo "Study PHP at $txt2";
echo "My car is a {$cars[0]}";
?>
The PHP print
Statement: print is also a language
construct, and can be used with or without parentheses: print or print().
<?php
print "<h2>PHP is
fun!</h2>";
print "Hello world!<br>";
print "I'm about to learn PHP!";
?>
PHP Data Types: String, Integer, Floating point numbers, Boolean,
Array, Object, NULL.
PHP Strings: characters, like "Hello world!", can be text inside
quotes. You can use single or double quotes:
PHP Integers: An integer is a number without decimals. Rules for integers:
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|
|
|
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In the following example we will test different
numbers. The PHP var_dump() function returns the data type and value of
variables:
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<?php
$x = 5985;
var_dump($x);
echo "<br>";
$x = -345; // negative number
var_dump($x);
echo "<br>";
$x = 0x8C; // hexadecimal number
var_dump($x);
echo "<br>";
$x = 047; // octal number
var_dump($x);
?>
$x = 5985;
var_dump($x);
echo "<br>";
$x = -345; // negative number
var_dump($x);
echo "<br>";
$x = 0x8C; // hexadecimal number
var_dump($x);
echo "<br>";
$x = 047; // octal number
var_dump($x);
?>
PHP Floating Point
Numbers: is a number with a decimal point or a number in
exponential form.
|
<?php
$x = 10.365;
var_dump($x);
echo "<br>";
$x = 2.4e3;
var_dump($x);
echo "<br>";
$x = 8E-5;
var_dump($x);
?>
$x = 10.365;
var_dump($x);
echo "<br>";
$x = 2.4e3;
var_dump($x);
echo "<br>";
$x = 8E-5;
var_dump($x);
?>
PHP Booleans: Booleans can be either TRUE or FALSE. Booleans are often used in
conditional testing.
PHP Arrays: An array stores multiple values in one single variable. In the
following example we create an array, and then use the var_dump() function to return the data type and
value of the array:
|
<?php
$cars=array("Volvo","BMW","Toyota");
var_dump($cars);
?>
$cars=array("Volvo","BMW","Toyota");
var_dump($cars);
?>
PHP Objects
Object is data type which stores data and
information on how to process that data. Object must be explicitly declared.
First we must declare a class of object. For
this, we use the class keyword. A class is a structure that can contain
properties and methods.
We then define the data type in the object
class, and then we use the data type in instances of that class:
|
<?php
class Car
{
var $color;
function Car($color="green")
{
$this->color = $color;
}
function what_color()
{
return $this->color;
}
}
function print_vars($obj)
{
foreach (get_object_vars($obj) as $prop => $val)
{
echo "\t$prop = $val\n";
}
}
// instantiate one object
$herbie = new Car("white");
// show herbie properties
echo "\herbie: Properties\n";
print_vars($herbie);
?>
class Car
{
var $color;
function Car($color="green")
{
$this->color = $color;
}
function what_color()
{
return $this->color;
}
}
function print_vars($obj)
{
foreach (get_object_vars($obj) as $prop => $val)
{
echo "\t$prop = $val\n";
}
}
// instantiate one object
$herbie = new Car("white");
// show herbie properties
echo "\herbie: Properties\n";
print_vars($herbie);
?>
PHP NULL Value
a variable has no value. NULL is the only
possible value of data type NULL. The NULL value identifies whether a variable
is empty or not. Also useful to differentiate between the empty string and null
values of databases. Variables can be emptied by setting the value to NULL:
PHP String Functions
The PHP strlen()
function
The strlen() function returns the length of a
string, in characters. The example below returns the length of the string
<?php
echo strlen("Hello world!");
?>
Tip: strlen() is often used in loops or other functions, when it
is important to know when a string ends. (i.e. in a loop, we might want to stop
the loop after the last character in a string).
The PHP strpos()
function
The strpos() used to search for a specified
character or text within a string. If a match is found, it will return the
character position of the first match. If no match is found, it will return
FALSE.
<?php
echo strpos("Hello world!","world");
?>
echo strpos("Hello world!","world");
?>
The output of the code above will be: 6. Because
it start from 0
PHP Constants
Constants are like variables except that once they
are defined they cannot be changed or undefined.
A valid constant name starts with a letter or
underscore (no $ sign before the constant name).
Note: Unlike variables, constants are automatically global across
the entire script.
Set a PHP Constant
To set a constant, use the define() function -
it takes three parameters: The first parameter defines the name of the
constant, the second parameter defines the value of the constant, and the
optional third parameter specifies whether the constant name should be
case-insensitive. Default is false.
The example below creates a case-sensitive
constant, with the value of "Welcome to W3Schools.com!":
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<?php
// define a case-sensitive constant
define("GREETING", "Welcome to W3Schools.com!");
echo GREETING;
echo "<br>";
// will not output the value of the constant
echo greeting;
?>
// define a case-sensitive constant
define("GREETING", "Welcome to W3Schools.com!");
echo GREETING;
echo "<br>";
// will not output the value of the constant
echo greeting;
?>
|
<?php
// define a case-insensitive constant
define("GREETING", "Welcome to W3Schools.com!", true);
echo GREETING;
echo "<br>";
// will also output the value of the constant
echo greeting;
?>
// define a case-insensitive constant
define("GREETING", "Welcome to W3Schools.com!", true);
echo GREETING;
echo "<br>";
// will also output the value of the constant
echo greeting;
?>
PHP Operators
PHP Arithmetic Operators
Operator
|
Name
|
Example
|
Result
|
+
|
Addition
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$x + $y
|
Sum of $x and $y
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-
|
Subtraction
|
$x - $y
|
Difference of $x and $y
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*
|
Multiplication
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$x * $y
|
Product of $x and $y
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/
|
Division
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$x / $y
|
Quotient of $x and $y
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%
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Modulus
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$x % $y
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Remainder of $x divided by $y
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$x=10;
$y=6;
echo ($x + $y); // outputs 16 echo ($x - $y); //
outputs 4 echo ($x * $y); // outputs 60 echo ($x / $y); // outputs
1.6666666666667 echo ($x % $y); // outputs 4
PHP Assignment Operators
Assignment
|
Same as...
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Description
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x = y
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x = y
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The left operand gets set to the value of the expression
on the right
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x += y
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x = x + y
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Addition
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x -= y
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x = x - y
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Subtraction
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x *= y
|
x = x * y
|
Multiplication
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x /= y
|
x = x / y
|
Division
|
x %= y
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x = x % y
|
Modulus
|
<?php
$x=10;
echo $x; // outputs 10
$y=20;
$y += 100;
echo $y; // outputs 120
$z=50;
$z -= 25;
echo $z; // outputs 25
$i=5;
$i *= 6;
echo $i; // outputs 30
$j=10;
$j /= 5;
echo $j; // outputs 2
$k=15;
$k %= 4;
echo $k; // outputs 3
?>
$x=10;
echo $x; // outputs 10
$y=20;
$y += 100;
echo $y; // outputs 120
$z=50;
$z -= 25;
echo $z; // outputs 25
$i=5;
$i *= 6;
echo $i; // outputs 30
$j=10;
$j /= 5;
echo $j; // outputs 2
$k=15;
$k %= 4;
echo $k; // outputs 3
?>
PHP String Operators
Operator
|
Name
|
Example
|
Result
|
.
|
Concatenation
|
$txt1 = "Hello"
$txt2 = $txt1 . " world!"
|
Now $txt2 contains "Hello world!"
|
.=
|
Concatenation assignment
|
$txt1 = "Hello"
$txt1 .= " world!"
|
Now $txt1 contains "Hello world!"
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<?php
$a = "Hello";
$b = $a . " world!";
echo $b; // outputs Hello world!
$x="Hello";
$x .= " world!";
echo $x; // outputs Hello world!
?>
$a = "Hello";
$b = $a . " world!";
echo $b; // outputs Hello world!
$x="Hello";
$x .= " world!";
echo $x; // outputs Hello world!
?>
PHP Increment /
Decrement Operators
Operator
|
Name
|
Description
|
++$x
|
Pre-increment
|
Increments $x by one, then returns $x
|
$x++
|
Post-increment
|
Returns $x, then increments $x by one
|
--$x
|
Pre-decrement
|
Decrements $x by one, then returns $x
|
$x--
|
Post-decrement
|
Returns $x, then decrements $x by one
|
<?php
$x=10;
echo ++$x; // outputs 11
$y=10;
echo $y++; // outputs 10
$z=5;
echo --$z; // outputs 4
$i=5;
echo $i--; // outputs 5
?>
$x=10;
echo ++$x; // outputs 11
$y=10;
echo $y++; // outputs 10
$z=5;
echo --$z; // outputs 4
$i=5;
echo $i--; // outputs 5
?>
PHP Comparison
Operators: used to compare two
values (number or string):
Operator
|
Name
|
Example
|
Result
|
==
|
Equal
|
$x == $y
|
True if $x is equal to $y
|
===
|
Identical
|
$x === $y
|
True if $x is equal to $y, and they are of the same type
|
!=
|
Not equal
|
$x != $y
|
True if $x is not equal to $y
|
<>
|
Not equal
|
$x <> $y
|
True if $x is not equal to $y
|
!==
|
Not identical
|
$x !== $y
|
True if $x is not equal to $y, or they are not of the same
type
|
>
|
Greater than
|
$x > $y
|
True if $x is greater than $y
|
<
|
Less than
|
$x < $y
|
True if $x is less than $y
|
>=
|
Greater than or equal to
|
$x >= $y
|
True if $x is greater than or equal to $y
|
<=
|
Less than or equal to
|
$x <= $y
|
True if $x is less than or equal to $y
|
<?php
$x=100;
$y="100";
var_dump($x == $y);
echo "<br>";
var_dump($x === $y);
echo "<br>";
var_dump($x != $y);
echo "<br>";
var_dump($x !== $y);
echo "<br>";
$a=50;
$b=90;
var_dump($a > $b);
echo "<br>";
var_dump($a < $b);
?>
$x=100;
$y="100";
var_dump($x == $y);
echo "<br>";
var_dump($x === $y);
echo "<br>";
var_dump($x != $y);
echo "<br>";
var_dump($x !== $y);
echo "<br>";
$a=50;
$b=90;
var_dump($a > $b);
echo "<br>";
var_dump($a < $b);
?>
PHP Logical Operators
Operator
|
Name
|
Example
|
Result
|
and
|
And
|
$x and $y
|
True if both $x and $y are true
|
or
|
Or
|
$x or $y
|
True if either $x or $y is true
|
xor
|
Xor
|
$x xor $y
|
True if either $x or $y is true, but not both
|
&&
|
And
|
$x && $y
|
True if both $x and $y are true
|
||
|
Or
|
$x || $y
|
True if either $x or $y is true
|
!
|
Not
|
!$x
|
True if $x is not true
|
PHP Array Operators
The PHP array operators are used to compare
arrays:
Operator
|
Name
|
Example
|
Result
|
+
|
Union
|
$x + $y
|
Union of $x and $y (but duplicate keys are not
overwritten)
|
==
|
Equality
|
$x == $y
|
True if $x and $y have the same key/value
|
===
|
Identity
|
$x === $y
|
True if $x and $y have the same key/value pairs in the
same order and of the same types
|
!=
|
Inequality
|
$x != $y
|
True if $x is not equal to $y
|
<>
|
Inequality
|
$x <> $y
|
True if $x is not equal to $y
|
!==
|
Non-identity
|
$x !== $y
|
True if $x is not identical to $y
|
<?php
$x = array("a" => "red",
"b" => "green");
$y = array("c" => "blue",
"d" => "yellow");
$z = $x + $y; // union of $x and $y
var_dump($z); var_dump($x
== $y); var_dump($x === $y); var_dump($x !=
$y); var_dump($x <> $y); var_dump($x !== $y);
?>
PHP if...else...elseif Statements
- if
statement - executes some code only
if a specified condition is true
- if...else
statement - executes some code if a
condition is true and another code if the condition is false
- if...elseif....else
statement - selects one of several
blocks of code to be executed
- switch
statement - selects one of many
blocks of code to be executed
The if statement is used to execute some
code only if a specified condition is true.
The example below will output "Have a good
day!" if the current time (HOUR) is less than 20:
|
<?php
$t=date("H");
if ($t<"20")
{
echo "Have a good day!";
}
?>
The example below will output "Have a good
morning!" if the current time is less than 10, and "Have a good
day!" if the current time is less than 20. Otherwise it will output
"Have a good night!":
<?php
$t=date("H");
if ($t<"10")
{
echo "Have a good morning!";
}
elseif ($t<"20")
{
echo "Have a good day!";
}
else
{
echo "Have a good night!";
}
?>
$t=date("H");
if ($t<"10")
{
echo "Have a good morning!";
}
elseif ($t<"20")
{
echo "Have a good day!";
}
else
{
echo "Have a good night!";
}
?>
The PHP switch Statement
This is how it works: First we have a single
expression n (most often a variable), that is evaluated once.
The value of the expression is then compared with the values for each case in
the structure. If there is a match, the block of code associated with that case
is executed. Use break to prevent the code from running into
the next case automatically. The default statement is used if
no match is found.
|
<?php
$favcolor="red";
switch ($favcolor)
{
case "red":
echo "Your favorite color is red!";
break;
case "blue":
echo "Your favorite color is blue!";
break;
case "green":
echo "Your favorite color is green!";
break;
default:
echo "Your favorite color is neither red, blue, or green!";
}
?>
$favcolor="red";
switch ($favcolor)
{
case "red":
echo "Your favorite color is red!";
break;
case "blue":
echo "Your favorite color is blue!";
break;
case "green":
echo "Your favorite color is green!";
break;
default:
echo "Your favorite color is neither red, blue, or green!";
}
?>
PHP Loops
You want the same block of code to run over and
over again in a row. Instead of adding several almost equal code-lines in a
script, we can use loops to perform a task like this. In PHP, we have the
following looping statements:
- while - loops through a block of code as long as the
specified condition is true
- do...while - loops through a block of code once, and then
repeats the loop as long as the specified condition is true
- for - loops through a block of code a specified number of
times
- foreach - loops through a block of code for each element in an
array
The PHP while Loop: The while loop executes a block of code as long as the specified
condition is true.
The example below first sets a variable $x to 1
($x=1;). Then, the while loop will continue to run as long as $x is less than,
or equal to 5. $x will increase by 1 each time the loop runs ($x++;):
<?php
$x=1;
while($x<=5)
{
echo "The number is: $x
<br>";
$x++;
}
?>
do...while Loop
The do...while loop will always execute the
block of code once, it will then check the condition, and repeat the loop while
the specified condition is true.
do
{
code to be executed;
}
}
while (condition is true);
The example below first sets a variable $x to 1
($x=1;). Then, the do while loop will write some output, and then increment the
variable $x with 1. Then the condition is checked (is $x less than, or equal to
5?), and the loop will continue to run as long as $x is less than, or equal to
5:
<?php
$x=1;
do
{
echo "The number is: $x <br>";
$x++;
}
while ($x<=5)
?>
$x=1;
do
{
echo "The number is: $x <br>";
$x++;
}
while ($x<=5)
?>
Notice that in a do while loop the condition is
tested AFTER executing the statements within the loop. This means that the do
while loop would execute its statements at least once, even if the condition
fails the first time.
The example below sets the $x variable to 6,
then it runs the loop, and then the condition is checked:
<?php
$x=6;
do
{
echo "The number is: $x <br>";
$x++;
}
while ($x<=5)
?>
$x=6;
do
{
echo "The number is: $x <br>";
$x++;
}
while ($x<=5)
?>
PHP for Loops
The for loop is used when you know in advance
how many times the script should run.
Syntax
for (init counter; test counter; increment
counter)
{
code to be executed;
}
Parameters:
- init
counter: Initialize the loop counter
value
- test
counter: Evaluated for each loop
iteration. If it evaluates to TRUE, the loop continues. If it evaluates to
FALSE, the loop ends.
- increment
counter: Increases the loop counter
value
The example below displays the numbers from 0 to
10:
<?php
for ($x=0; $x<=10; $x++)
{
echo "The number is: $x
<br>";
}
?>
The PHP foreach
Loop: The foreach loop works
only on arrays, and is used to loop through each key/value pair in an array.
foreach ($array as $value)
{
code to be executed;
}
For every loop iteration, the value of the
current array element is assigned to $value and the array pointer is moved by
one, until it reaches the last array element. The example demonstrates a loop
that will output the values of the given array ($colors):
|
<?php
$colors = array("red","green","blue","yellow");
foreach ($colors as $value)
{
echo "$value <br>";
}
?>
$colors = array("red","green","blue","yellow");
foreach ($colors as $value)
{
echo "$value <br>";
}
?>
PHP Functions
The real power of PHP comes from its functions;
it has more than 1000 built-in functions.
PHP User Defined
Functions
Besides the built-in PHP functions, we can
create our own functions.
A function is a block of statements that can be
used repeatedly in a program.
A function will not execute immediately when a
page loads.
A function will be executed by a call to the
function.
Create a User Defined
Function in PHP
<?php
function writeMsg()
{
echo "Hello world!";
}
writeMsg(); // call the function
?>
function writeMsg()
{
echo "Hello world!";
}
writeMsg(); // call the function
?>
Note: A function name can start with a letter or underscore (not a
number).
Remember that function names are
case-insensitive.
PHP Function Arguments
Information can be passed to functions through
arguments. An argument is just like a variable. Specified after the function
name, inside the parentheses. You can add as many arguments as you want,
seperate them with a comma.
<?php
function familyName($fname,$year)
{
echo "$fname Refsnes. Born in $year <br>";
}
familyName("Hege","1975");
familyName("Ståle","1978");
familyName("Kai Jim","1983");
?>
function familyName($fname,$year)
{
echo "$fname Refsnes. Born in $year <br>";
}
familyName("Hege","1975");
familyName("Ståle","1978");
familyName("Kai Jim","1983");
?>
The following example shows how to use a default
parameter. If we call the function setHeight() without arguments it takes the
default value as argument:
<?php
function setHeight($minheight=50)
{
echo "The height is : $minheight <br>";
}
setHeight(350);
setHeight(); // will use the default value of 50
setHeight(135);
setHeight(80);
?>
function setHeight($minheight=50)
{
echo "The height is : $minheight <br>";
}
setHeight(350);
setHeight(); // will use the default value of 50
setHeight(135);
setHeight(80);
?>
PHP Functions -
Returning values
<?php
function sum($x,$y)
{
$z=$x+$y;
return $z;
}
echo "5 + 10 = " . sum(5,10) . "<br>";
echo "7 + 13 = " . sum(7,13) . "<br>";
echo "2 + 4 = " . sum(2,4);
?>
function sum($x,$y)
{
$z=$x+$y;
return $z;
}
echo "5 + 10 = " . sum(5,10) . "<br>";
echo "7 + 13 = " . sum(7,13) . "<br>";
echo "2 + 4 = " . sum(2,4);
?>
PHP Arrays: An array stores multiple values in one single
variable:
<?php
$cars=array("Volvo","BMW","Toyota");
echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] . ".";
?>
$cars=array("Volvo","BMW","Toyota");
echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] . ".";
?>
Create an Array in
PHP: In PHP, the array()
function is used to create an array: array();
In PHP, there are three types of arrays:
- Indexed
arrays - Arrays with numeric
index
- Associative
arrays - Arrays with named keys
- Multidimensional
arrays - Arrays containing one
or more arrays
PHP Indexed Arrays
There are two ways to create indexed arrays:
The index can be assigned automatically (index
always starts at 0): $cars=array("Volvo","BMW","Toyota");
or the index can be assigned manually:
$cars[0]="Volvo"; $cars[1]="BMW"; $cars[2]="Toyota";
Get The Length of an Array - The count()
Function
The count() function is used to return the
length (the number of elements) of an array:
<?php
$cars=array("Volvo","BMW","Toyota");
echo count($cars);
?>
$cars=array("Volvo","BMW","Toyota");
echo count($cars);
?>
Loop Through an Indexed Array: To loop through and print all the values of an
indexed array, you use a for loop, like this:
<?php
$cars=array("Volvo","BMW","Toyota");
$arrlength=count($cars);
for($x=0;$x<$arrlength;$x++)
{
echo $cars[$x];
echo "<br>";
}
?>
$cars=array("Volvo","BMW","Toyota");
$arrlength=count($cars);
for($x=0;$x<$arrlength;$x++)
{
echo $cars[$x];
echo "<br>";
}
?>
PHP Associative Arrays
Associative arrays are arrays that use named
keys that you assign to them.
There are two ways to create an associative
array:
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
or:
$age['Peter']="35";
$age['Ben']="37";
$age['Joe']="43";
$age['Ben']="37";
$age['Joe']="43";
The named keys can then be used in a script:
<?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
echo "Peter is " . $age['Peter'] . " years old.";
?>
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
echo "Peter is " . $age['Peter'] . " years old.";
?>
Loop Through an Associative Array
|
<?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
foreach($age as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "<br>";
}
?>
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
foreach($age as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "<br>";
}
?>
Explain foreach ($age as $x=>$x_value)
We assign the keys ("peter") of array
to $x variable and we assign the values to the variable $x_value "35"
PHP Multidimensional
Arrays: An
array can also contain another array as a value, which in turn can hold other
arrays as well. In such a way we can create two- or three-dimensional arrays:
|
<?php
// A two-dimensional array
$cars = array
(
array("Volvo",100,96),
array("BMW",60,59),
array("Toyota",110,100)
);
echo $cars[0][0].": Ordered: ".$cars[0][1].". Sold: ".$cars[0][2]."<br>";
echo $cars[1][0].": Ordered: ".$cars[1][1].". Sold: ".$cars[1][2]."<br>";
echo $cars[2][0].": Ordered: ".$cars[2][1].". Sold: ".$cars[2][2]."<br>";
?>
// A two-dimensional array
$cars = array
(
array("Volvo",100,96),
array("BMW",60,59),
array("Toyota",110,100)
);
echo $cars[0][0].": Ordered: ".$cars[0][1].". Sold: ".$cars[0][2]."<br>";
echo $cars[1][0].": Ordered: ".$cars[1][1].". Sold: ".$cars[1][2]."<br>";
echo $cars[2][0].": Ordered: ".$cars[2][1].". Sold: ".$cars[2][2]."<br>";
?>
PHP - Multidimensional
Arrays: In a multidimensional array, each element in the
main array can also be an array. And each element in the sub-array can be an
array, and so on.
In this example we create a multidimensional
array, with automatically assigned ID keys:
$families = array
(
"Griffin"=>array
(
"Peter",
"Lois",
"Megan"
),
"Quagmire"=>array
(
"Glenn"
),
"Brown"=>array
(
"Cleveland",
"Loretta",
"Junior"
)
);
The array above would look like this if written
to the output:
Array
(
[Griffin] => Array
(
[0] => Peter
[1] => Lois
[2] => Megan
)
[Quagmire] => Array
(
[0] => Glenn
)
[Brown] => Array
(
[0] => Cleveland
[1] => Loretta
[2] => Junior
)
)
Lets try displaying a single value from the
array above:
echo "Is " . $families['Griffin'][2] .
" a part of the Griffin family?";
The code above will output:
Is Megan a part of the Griffin family?
PHP Sorting Arrays
The elements in an array can be sorted in
alphabetical or numerical order, descending or ascending.
PHP - Sort Functions For
Arrays
- sort()
- sort arrays in ascending order
- rsort() - sort arrays in
descending order
- asort()
- sort associative arrays in ascending order, according to the value
- ksort()
- sort associative arrays in ascending order, according to the key
- arsort()
- sort associative arrays in descending order, according to the value
- krsort()
- sort associative arrays in descending order, according to the key
Sort Array in Ascending
Order - sort()
|
<?php
$cars=array("Volvo","BMW","Toyota");
sort($cars);
$clength=count($cars);
for($x=0;$x<$clength;$x++)
{
echo $cars[$x];
echo "<br>";
}
?>
$cars=array("Volvo","BMW","Toyota");
sort($cars);
$clength=count($cars);
for($x=0;$x<$clength;$x++)
{
echo $cars[$x];
echo "<br>";
}
?>
Sort Array in Ascending
Order, According to Value - asort()
The following example sorts an associative array
in ascending order, according to the value:
|
<?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
asort($age);
foreach($age as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "<br>";
}
?>
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
asort($age);
foreach($age as $x=>$x_value)
{
echo "Key=" . $x . ", Value=" . $x_value;
echo "<br>";
}
?>
PHP Global
Variables - Superglobals
Superglobals were introduced in PHP 4.1.0, and
are built-in variables that are always available in all scopes.
PHP Global Variables -
Superglobals
Several predefined variables in PHP are
"superglobals", which means that they are always accessible,
regardless of scope - and you can access them from any function, class or file
without having to do anything special.
$GLOBALS
|
$_SERVER
|
$_REQUEST
|
$_POST
|
$_GET
|
$_ENV
|
$_COOKIE
|
$_SESSION
|
$_FILES
|
PHP $GLOBAL
$GLOBAL is a PHP super global variable which is
used to access global variables from anywhere in the PHP script (also from
within functions or methods).
PHP stores all global variables in an array
called $GLOBALS[index]. The index holds the name of the
variable.
The example below shows how to use the super
global variable $GLOBAL:
<?php
$x = 75;
$y = 25;
function addition()
{
$GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y'];
}
addition();
echo $z;
?>
$x = 75;
$y = 25;
function addition()
{
$GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y'];
}
addition();
echo $z;
?>
In the example above, since z is a variable
present within the $GLOBALS array, it is also accessible form outside the
function!
PHP $_SERVER
$_SERVER is a PHP super global variable which
holds information about headers, paths, and script locations.
The example below shows how to use some of the
elements in $_SERVER:
|
<?php
echo $_SERVER['PHP_SELF'];
echo "<br>";
echo $_SERVER['SERVER_NAME'];
echo "<br>";
echo $_SERVER['HTTP_HOST'];
echo "<br>";
echo $_SERVER['HTTP_REFERER'];
echo "<br>";
echo $_SERVER['HTTP_USER_AGENT'];
echo "<br>";
echo $_SERVER['SCRIPT_NAME'];
?>
echo $_SERVER['PHP_SELF'];
echo "<br>";
echo $_SERVER['SERVER_NAME'];
echo "<br>";
echo $_SERVER['HTTP_HOST'];
echo "<br>";
echo $_SERVER['HTTP_REFERER'];
echo "<br>";
echo $_SERVER['HTTP_USER_AGENT'];
echo "<br>";
echo $_SERVER['SCRIPT_NAME'];
?>
The following table lists the most important
elements that can go inside $_SERVER:
Element/Code
|
Description
|
$_SERVER['PHP_SELF']
|
Returns the filename of the currently executing script
|
$_SERVER['GATEWAY_INTERFACE']
|
Returns the version of the Common Gateway Interface (CGI)
the server is using
|
$_SERVER['SERVER_ADDR']
|
Returns the IP address of the host server
|
$_SERVER['SERVER_NAME']
|
Returns the name of the host server (such as
www.w3schools.com)
|
$_SERVER['SERVER_SOFTWARE']
|
Returns the server identification string (such as
Apache/2.2.24)
|
$_SERVER['SERVER_PROTOCOL']
|
Returns the name and revision of the information protocol
(such as HTTP/1.1)
|
$_SERVER['REQUEST_METHOD']
|
Returns the request method used to access the page (such
as POST)
|
$_SERVER['REQUEST_TIME']
|
Returns the timestamp of the start of the request (such as
1377687496)
|
$_SERVER['QUERY_STRING']
|
Returns the query string if the page is accessed via a
query string
|
$_SERVER['HTTP_ACCEPT']
|
Returns the Accept header from the current request
|
$_SERVER['HTTP_ACCEPT_CHARSET']
|
Returns the Accept_Charset header from the current request
(such as utf-8,ISO-8859-1)
|
$_SERVER['HTTP_HOST']
|
Returns the Host header from the current request
|
$_SERVER['HTTP_REFERER']
|
Returns the complete URL of the current page (not reliable
because not all user-agents support it)
|
$_SERVER['HTTPS']
|
Is the script queried through a secure HTTP protocol
|
$_SERVER['REMOTE_ADDR']
|
Returns the IP address from where the user is viewing the
current page
|
$_SERVER['REMOTE_HOST']
|
Returns the Host name from where the user is viewing the
current page
|
$_SERVER['REMOTE_PORT']
|
Returns the port being used on the user's machine to
communicate with the web server
|
$_SERVER['SCRIPT_FILENAME']
|
Returns the absolute pathname of the currently executing
script
|
$_SERVER['SERVER_ADMIN']
|
Returns the value given to the SERVER_ADMIN directive in
the web server configuration file (if your script runs on a virtual host, it
will be the value defined for that virtual host) (such as
someone@w3scholls.com)
|
$_SERVER['SERVER_PORT']
|
Returns the port on the server machine being used by the
web server for communication (such as 80)
|
$_SERVER['SERVER_SIGNATURE']
|
Returns the server version and virtual host name which are
added to server-generated pages
|
$_SERVER['PATH_TRANSLATED']
|
Returns the file system based path to the current script
|
$_SERVER['SCRIPT_NAME']
|
Returns the path of the current script
|
$_SERVER['SCRIPT_URI']
|
Returns the URI of the current page
|
PHP $_REQUEST
PHP $_REQUEST is used to collect data after
submitting an HTML form.
The example below shows a form with an input
field and a submit button. When a user submits the data by clicking on
"Submit", the form data is sent to the file specified in the action
attribute of the <form> tag.
<form
method="post" action="<?php echo
$_SERVER['PHP_SELF'];?>">
Name: <input type="text" name="fname">
<input type="submit">
</form>
<?php
$name = $_REQUEST['fname'];
echo $name;
?>
Name: <input type="text" name="fname">
<input type="submit">
</form>
<?php
$name = $_REQUEST['fname'];
echo $name;
?>
PHP $_POST
PHP $_POST is widely used to collect form data
after submitting an HTML form with method="post". $_POST is also
widely used to pass variables. The example below shows a form with an input
field and a submit button. When a user submits the data by clicking on
"Submit", the form data is sent to the file specified in the action
attribute of the <form> tag.
<body>
<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
Name: <input type="text" name="fname">
<input type="submit">
</form>
<?php
$name = $_POST['fname'];
echo $name;
?>
</body>
<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
Name: <input type="text" name="fname">
<input type="submit">
</form>
<?php
$name = $_POST['fname'];
echo $name;
?>
</body>
PHP $_GET
PHP $_GET can also be used to collect form data
after submitting an HTML form with method="get".
$_GET can also collect data sent in the URL.
PHP Form
Handling: The PHP superglobals
$_GET and $_POST are used to collect form-data.
PHP - A Simple HTML Form
The example below displays a simple HTML form
with two input fields and a submit button:
<html>
<body>
<form action="welcome.php"
method="post">
Name: <input type="text"
name="name"><br>
E-mail: <input type="text"
name="email"><br>
<input type="submit">
</form>
</body>
</html>
When the user fills out the form above and
clicks the submit button, the form data is sent for processing to a PHP file
named "welcome.php". The form data is sent with the HTTP POST method.
To display the submitted data you could simply
echo all the variables. The "welcome.php" looks like this:
<html>
<body>
Welcome <?php echo $_POST["name"]; ?><br>
Your email address is: <?php echo $_POST["email"]; ?>
</body>
</html>
<body>
Welcome <?php echo $_POST["name"]; ?><br>
Your email address is: <?php echo $_POST["email"]; ?>
</body>
</html>
The output could be something like this:
Welcome John
Your email address is john.doe@example.com
Your email address is john.doe@example.com
The same result could also be achieved using the
HTTP GET method:
Think SECURITY when processing PHP forms!
This page does not contain any form validation,
it just shows how you can send and retrieve form data.
However, the next pages will show how to process
PHP forms with security in mind! Proper validation of form data is important to
protect your form from hackers and spammers!
GET vs. POST
Both GET and POST create an array (e.g. array(
key => value, key2 => value2, key3 => value3, ...)). This array holds
key/value pairs, where keys are the names of the form controls and values are
the input data from the user.
Both GET and POST are treated as $_GET and
$_POST. These are superglobals, which means that they are always accessible,
regardless of scope - and you can access them from any function, class or file
without having to do anything special.
$_GET is an array of variables passed to the
current script via the URL parameters.
$_POST is an array of variables passed to the
current script via the HTTP POST method.
When to use GET?
Information sent from a form with the GET method
is visible to everyone (all variable names and values are
displayed in the URL). GET also has limits on the amount of information to
send. The limitation is about 2000 characters. However, because the variables
are displayed in the URL, it is possible to bookmark the page. This can be
useful in some cases.
GET may be used for sending non-sensitive data.
Note: GET should NEVER be used for sending passwords or other
sensitive information!
When to use POST?
Information sent from a form with the POST
method is invisible to others (all names/values are embedded
within the body of the HTTP request) and has no limits on the
amount of information to send.
Moreover POST supports advanced functionality
such as support for multi-part binary input while uploading files to server.
However, because the variables are not displayed
in the URL, it is not possible to bookmark the page.
PHP Form Validation
The HTML form we will be working at in these
chapters, contains various input fields: required and optional text fields,
radio buttons, and a submit button:
|
First we will look at the plain HTML code for
the form:
Text Fields
The name, email, and website fields are text
input elements, and the comment field is a textarea. The HTML code looks like
this:
Name: <input type="text"
name="name">
E-mail: <input type="text"
name="email">
Website: <input type="text"
name="website">
Comment: <textarea name="comment"
rows="5" cols="40"></textarea>
Radio Buttons
The gender fields are radio buttons and the HTML
code looks like this:
Gender:
<input type="radio"
name="gender" value="female">Female
<input type="radio"
name="gender" value="male">Male
The Form Element
The HTML code of the form looks like this:
<form method="post"
action="<?php echo
htmlspecialchars($_SERVER["PHP_SELF"]);?>">
What is the $_SERVER["PHP_SELF"]
variable?
The $_SERVER["PHP_SELF"] is a super
global variable that returns the filename of the currently executing script.
So, the $_SERVER["PHP_SELF"] sends the
submitted form data to the page itself, instead of jumping to a different page.
This way, the user will get error messages on the same page as the form.
What is the htmlspecialchars() function?
The htmlspecialchars() function converts special
characters to HTML entities. This means that it will replace HTML characters
like < and > with < and >. This prevents attackers from
exploiting the code by injecting HTML or Javascript code (Cross-site Scripting
attacks) in forms.
Big Note on PHP Form
Security
The $_SERVER["PHP_SELF"] variable can
be used by hackers!
If PHP_SELF is used in your page then a user can
enter a slash (/) and then some Cross Site Scripting (XSS) commands to execute.
Cross-site scripting (XSS) is a type of computer
security vulnerability قابل للاختراق typically found in
Web applications. XSS enables attackers to inject client-side script into Web
pages viewed by other users.
Assume we have the following form in a page
named "test_form.php":
<form method="post"
action="<?php echo $_SERVER["PHP_SELF"];?>">
Now, if a user enters the normal URL in the
address bar like "http://www.example.com/test_form.php", the above
code will be translated to:
<form method="post"
action="test_form.php">
So far, so good.
However, consider that a user enters the
following URL in the address bar:
http://www.example.com/test_form.php/%22%3E%3Cscript%3Ealert('hacked')%3C/script%3E
In this case, the above code will be translated
to:
<form method="post"
action="test_form.php"/><script>alert('hacked')</script>
This code adds a script tag and an alert
command. And when the page loads, the JavaScript code will be executed (the
user will see an alert box). This is just a simple and harmless example how the
PHP_SELF variable can be exploited استخدم. Be aware of that any JavaScript
code can be added inside the <script> tag! A hacker can redirect
the user to a file on another server, and that file can hold malicious code
that can alter the global variables or submit the form to another address to
save the user data, for example.
How To Avoid
$_SERVER["PHP_SELF"] Exploits?
$_SERVER["PHP_SELF"] exploits can be
avoided by using the htmlspecialchars() function.
The form code should look like this:
<form method="post"
action="<?php echo
htmlspecialchars($_SERVER["PHP_SELF"]);?>">
The htmlspecialchars() function converts special
characters to HTML entities. Now if the user tries to exploit the PHP_SELF
variable, it will result in the following output:
<form method="post"
action="test_form.php/"><script>alert('hacked')</script>">
The exploit attempt fails, and no harm is done!
Validate Form Data With PHP
The first thing we will do is to pass all
variables through PHP's htmlspecialchars() function.
When we use the htmlspecialchars() function;
then if a user tries to submit the following in a text field:
<script>location.href('http://www.hacked.com')</script>
- this would not be executed, because it would
be saved as HTML escaped code, like this:
<script>location.href('http://www.hacked.com')</script>
The code is now safe to be displayed on a page
or inside an e-mail.
We will also do two more things when the user
submits the form:
- Strip
unnecessary characters (extra space, tab, newline) from the user input
data (with the PHP trim() function)
- Remove
backslashes (\) from the user input data (with the PHP stripslashes()
function)
The next step is to create a function that will
do all the checking for us (which is much more convenient than writing the same
code over and over again).
We will name the function test_input().
Now, we can check each $_POST variable with the
test_input() function, and the script look like this:
<?php
// define variables and set to empty values
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST")
{
$name = test_input($_POST["name"]);
$email = test_input($_POST["email"]);
$website = test_input($_POST["website"]);
$comment = test_input($_POST["comment"]);
$gender = test_input($_POST["gender"]);
}
function test_input($data)
{
// define variables and set to empty values
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST")
{
$name = test_input($_POST["name"]);
$email = test_input($_POST["email"]);
$website = test_input($_POST["website"]);
$comment = test_input($_POST["comment"]);
$gender = test_input($_POST["gender"]);
}
function test_input($data)
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
Notice that at the start of the script, we check
whether the form has been submitted using $_SERVER["REQUEST_METHOD"].
If the REQUEST_METHOD is POST, then the form has been submitted - and it should
be validated. If it has not been submitted, skip the validation and display a
blank form.
However, in the example above, all input fields
are optional. The script works fine even if the user do not enter any data.The next
step is to make input fields required and create error messages if needed.
PHP Forms
- Required Fields
Field
|
Validation Rules
|
Name
|
Required. + Must only contain letters and whitespace
|
E-mail
|
Required. + Must contain a valid email address (with @ and
.)
|
Website
|
Optional. If present, it must contain a valid URL
|
Comment
|
Optional. Multi-line input field (textarea)
|
Gender
|
Required. Must select one
|
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST")
{
if (empty($_POST["name"]))
{$nameErr = "Name is required";}
else
{$name = test_input($_POST["name"]);}
if (empty($_POST["email"]))
{$emailErr = "Email is required";}
else
{$email = test_input($_POST["email"]);}
if (empty($_POST["website"]))
{$website = "";}
else
{$website = test_input($_POST["website"]);}
if (empty($_POST["comment"]))
{$comment = "";}
else
{$comment = test_input($_POST["comment"]);}
if (empty($_POST["gender"]))
{$genderErr = "Gender is required";}
else
{$gender = test_input($_POST["gender"]);}
}
?>
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST")
{
if (empty($_POST["name"]))
{$nameErr = "Name is required";}
else
{$name = test_input($_POST["name"]);}
if (empty($_POST["email"]))
{$emailErr = "Email is required";}
else
{$email = test_input($_POST["email"]);}
if (empty($_POST["website"]))
{$website = "";}
else
{$website = test_input($_POST["website"]);}
if (empty($_POST["comment"]))
{$comment = "";}
else
{$comment = test_input($_POST["comment"]);}
if (empty($_POST["gender"]))
{$genderErr = "Gender is required";}
else
{$gender = test_input($_POST["gender"]);}
}
?>
<html><head><style>.error
{color: #FF0000;}</style></head><body>
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST")
{
if (empty($_POST["name"]))
{$nameErr = "Name is required";}
else
{$name = test_input($_POST["name"]);}
if (empty($_POST["email"]))
{$emailErr = "Email is required";}
else
{$email = test_input($_POST["email"]);}
if (empty($_POST["website"]))
{$website = "";}
else
{$website = test_input($_POST["website"]);}
if (empty($_POST["comment"]))
{$comment = "";}
else
{$comment = test_input($_POST["comment"]);}
if (empty($_POST["gender"]))
{$genderErr = "Gender is required";}
else
{$gender = test_input($_POST["gender"]);}
}
function test_input($data)
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP Form Validation Example</h2><p><span class="error">* required field.</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Name: <input type="text" name="name">
<span class="error">* <?php echo $nameErr;?></span><br><br>
E-mail: <input type="text" name="email">
<span class="error">* <?php echo $emailErr;?></span><br><br>
Website: <input type="text" name="website">
<span class="error"><?php echo $websiteErr;?></span><br><br>
Comment: <textarea name="comment" rows="5" cols="40"></textarea><br><br>
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST")
{
if (empty($_POST["name"]))
{$nameErr = "Name is required";}
else
{$name = test_input($_POST["name"]);}
if (empty($_POST["email"]))
{$emailErr = "Email is required";}
else
{$email = test_input($_POST["email"]);}
if (empty($_POST["website"]))
{$website = "";}
else
{$website = test_input($_POST["website"]);}
if (empty($_POST["comment"]))
{$comment = "";}
else
{$comment = test_input($_POST["comment"]);}
if (empty($_POST["gender"]))
{$genderErr = "Gender is required";}
else
{$gender = test_input($_POST["gender"]);}
}
function test_input($data)
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP Form Validation Example</h2><p><span class="error">* required field.</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Name: <input type="text" name="name">
<span class="error">* <?php echo $nameErr;?></span><br><br>
E-mail: <input type="text" name="email">
<span class="error">* <?php echo $emailErr;?></span><br><br>
Website: <input type="text" name="website">
<span class="error"><?php echo $websiteErr;?></span><br><br>
Comment: <textarea name="comment" rows="5" cols="40"></textarea><br><br>
|
Gender:
<input type="radio" name="gender"
value="female">Female
<input type="radio" name="gender" value="male">Male
<span class="error">* <?php echo $genderErr;?></span><br><br>
<input type="submit" name="submit" value="Submit">
</form>
<?php
echo "<h2>Your Input:</h2>";
echo $name; echo "<br>"; echo $email; echo "<br>"; echo $website; echo "<br>";
echo $comment; echo "<br>"; echo $gender;
?>
</body></html>
<input type="radio" name="gender" value="male">Male
<span class="error">* <?php echo $genderErr;?></span><br><br>
<input type="submit" name="submit" value="Submit">
</form>
<?php
echo "<h2>Your Input:</h2>";
echo $name; echo "<br>"; echo $email; echo "<br>"; echo $website; echo "<br>";
echo $comment; echo "<br>"; echo $gender;
?>
</body></html>
PHP Forms
- Validate Names E-mail and URL
$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z ]*$/",$name))
{
$nameErr = "Only letters and white space allowed";
if (!preg_match("/^[a-zA-Z ]*$/",$name))
{
$nameErr = "Only letters and white space allowed";
^ Start of string, or the point after any
newline if in multiline match mode, /m.
$ End of search string, or the point before
a string-ending newline, or before any newline if in multiline match
mode, /m.
The preg_match() function searches a string for
pattern, returning true if the pattern exists, and false otherwise.
$email = test_input($_POST["email"]);
if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email))
{
$emailErr = "Invalid email format";
}
if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email))
{
$emailErr = "Invalid email format";
}
if
(!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website))
{
$websiteErr = "Invalid URL";
}
{
$websiteErr = "Invalid URL";
}
<!DOCTYPE
HTML>
<html>
<head>
<style>
<html>
<head>
<style>
|
.error
{color: #FF0000;}
</style>
</head>
<body>
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST")
{
if (empty($_POST["name"]))
{$nameErr = "Name is required";}
else
{
$name = test_input($_POST["name"]);
// check if name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$name))
{
$nameErr = "Only letters and white space allowed";
}
}
if (empty($_POST["email"]))
{$emailErr = "Email is required";}
else
{
$email = test_input($_POST["email"]);
// check if e-mail address syntax is valid
if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email))
{
$emailErr = "Invalid email format";
}
}
if (empty($_POST["website"]))
{$website = "";}
else
{
$website = test_input($_POST["website"]);
// check if URL address syntax is valid (this regular expression also allows dashes in the URL)
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website))
{
$websiteErr = "Invalid URL";
}
}
if (empty($_POST["comment"]))
{$comment = "";}
else
{$comment = test_input($_POST["comment"]);}
if (empty($_POST["gender"]))
{$genderErr = "Gender is required";}
else
{$gender = test_input($_POST["gender"]);}
}
function test_input($data)
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP Form Validation Example</h2>
<p><span class="error">* required field.</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Name: <input type="text" name="name">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
E-mail: <input type="text" name="email">
<span class="error">* <?php echo $emailErr;?></span>
<br><br>
Website: <input type="text" name="website">
<span class="error"><?php echo $websiteErr;?></span>
<br><br>
Comment: <textarea name="comment" rows="5" cols="40"></textarea>
<br><br>
Gender:
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
<span class="error">* <?php echo $genderErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">
</form>
<?php
echo "<h2>Your Input:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
</body>
</html>
</style>
</head>
<body>
<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST")
{
if (empty($_POST["name"]))
{$nameErr = "Name is required";}
else
{
$name = test_input($_POST["name"]);
// check if name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$name))
{
$nameErr = "Only letters and white space allowed";
}
}
if (empty($_POST["email"]))
{$emailErr = "Email is required";}
else
{
$email = test_input($_POST["email"]);
// check if e-mail address syntax is valid
if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email))
{
$emailErr = "Invalid email format";
}
}
if (empty($_POST["website"]))
{$website = "";}
else
{
$website = test_input($_POST["website"]);
// check if URL address syntax is valid (this regular expression also allows dashes in the URL)
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website))
{
$websiteErr = "Invalid URL";
}
}
if (empty($_POST["comment"]))
{$comment = "";}
else
{$comment = test_input($_POST["comment"]);}
if (empty($_POST["gender"]))
{$genderErr = "Gender is required";}
else
{$gender = test_input($_POST["gender"]);}
}
function test_input($data)
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP Form Validation Example</h2>
<p><span class="error">* required field.</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Name: <input type="text" name="name">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
E-mail: <input type="text" name="email">
<span class="error">* <?php echo $emailErr;?></span>
<br><br>
Website: <input type="text" name="website">
<span class="error"><?php echo $websiteErr;?></span>
<br><br>
Comment: <textarea name="comment" rows="5" cols="40"></textarea>
<br><br>
Gender:
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
<span class="error">* <?php echo $genderErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">
</form>
<?php
echo "<h2>Your Input:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
</body>
</html>
PHP Complete
Form Example
This chapter show how to keep the values in the
input fields when the user hits the submit button.
PHP - Keep The Values in
The Form
To show the values in the input fields after the
user hits the submit button, we add a little PHP script inside the value
attribute of the following input fields: name, email, and website. In the
comment textarea field, we put the script between the <textarea> and
</textarea> tags. The little script outputs the value of the $name,
$email, $website, and $comment variables. Then, we also need to show which
radio button that was checked. For this, we must manipulate the checked
attribute (not the value attribute for radio buttons):
Name: <input type="text"
name="name" value="<?php echo $name;?>">
E-mail: <input type="text"
name="email" value="<?php echo $email;?>">
Website: <input type="text" name="website" value="<?php echo $website;?>">
Comment: <textarea name="comment" rows="5" cols="40"><?php echo $comment;?></textarea>
Website: <input type="text" name="website" value="<?php echo $website;?>">
Comment: <textarea name="comment" rows="5" cols="40"><?php echo $comment;?></textarea>
Gender:
<input type="radio"
name="gender"
<?php if (isset($gender) &&
$gender=="female") echo "checked";?>
value="female">Female
<input type="radio"
name="gender"
<?php if (isset($gender) &&
$gender=="male") echo "checked";?>
value="male">Male
Regular expression
Regular Expression Rules
^
|
Start of String
|
|
$
|
End of string
|
|
n*
|
Zero or more of 'n'
|
|
n+
|
One or more of 'n'
|
|
n?
|
A possible 'n'
|
|
n{2}
|
Exactly two of 'n'
|
|
n{2,}
|
At least 2 or more of 'n'
|
|
n{2,4}
|
From 2 to 4 of 'n'
|
|
()
|
Parenthesis to group substrings
|
|
(n|a)
|
Either 'n' or 'a'
|
|
.
|
Any single character
|
|
[1-7]
|
A number between 1 and 7
|
|
[b-t]
|
A lower case character between b and t
|
|
[B-T]
|
An upper case character between B and T
|
|
[^a-z]
|
Absence of lower case a to z
|
|
[_a-zA-Z]
|
An underscore or any letter of the alpha
|
|
\w
|
Any upper or lower case letter or number or underscore
|
|
\W
|
Any character not in \w
|
|
\d
|
Any digit 0-9
|
|
\D
|
Any character not in \d
|
|
I
|
A modifier - goes at the end of the pattern string -
ignore case
|
|
\ |
Escape the next character \n matches a newline character \( or \) matches the parentheses \\ matches \ |
PHP Multidimensional
Arrays
|
<!DOCTYPE html>
<body>
<?php
// A two-dimensional array
$cars = array
(
array("Volvo",100,96),
array("BMW",60,59),
array("Toyota",110,100)
);
echo $cars[0][0].": Ordered: ".$cars[0][1].". Sold: ".$cars[0][2]."<br>";
echo $cars[1][0].": Ordered: ".$cars[1][1].". Sold: ".$cars[1][2]."<br>";
echo $cars[2][0].": Ordered: ".$cars[2][1].". Sold: ".$cars[2][2]."<br>";
?>
</body>
</html>
<body>
<?php
// A two-dimensional array
$cars = array
(
array("Volvo",100,96),
array("BMW",60,59),
array("Toyota",110,100)
);
echo $cars[0][0].": Ordered: ".$cars[0][1].". Sold: ".$cars[0][2]."<br>";
echo $cars[1][0].": Ordered: ".$cars[1][1].". Sold: ".$cars[1][2]."<br>";
echo $cars[2][0].": Ordered: ".$cars[2][1].". Sold: ".$cars[2][2]."<br>";
?>
</body>
</html>
In a multidimensional array, each element in the
main array can also be an array, each element in the sub-array can be an array,
and so on.
|
$families = array
(
"Griffin"=>array
(
"Peter",
"Lois",
"Megan"
),
"Quagmire"=>array
(
"Glenn"
),
"Brown"=>array
(
"Cleveland",
"Loretta",
"Junior"
)
);
(
"Griffin"=>array
(
"Peter",
"Lois",
"Megan"
),
"Quagmire"=>array
(
"Glenn"
),
"Brown"=>array
(
"Cleveland",
"Loretta",
"Junior"
)
);
Example 2: Lets try displaying a single value from the
array above:
echo "Is " . $families['Griffin'][2] .
" a part of the Griffin family?";
The code above will output: Is
Megan a part of the Griffin family?
PHP Date() Function
The PHP date() function is used to format a time
and/or date.
The PHP Date() Function
The PHP date() function formats a timestamp to a
more readable date and time.
A timestamp is a sequence of characters,
denoting the date and/or time at which a certain event occurred.
Syntax
date(format,timestamp)
Parameter
|
Description
|
format
|
Required. Specifies the format of the timestamp
|
timestamp
|
Optional. Specifies a timestamp. Default is the current
date and time
|
PHP Date() - Format the Date
The required format parameter
in the date() function specifies how to format the date/time.
Here are some characters that can be used:
d - Represents the day of the month (01 to 31) ,
m - Represents a month (01 to 12), Y - Represents a year (4 digits)
A list of all the characters that can be used in
the format parameter, can be found in our PHP Date
reference, date() function.
Other characters, like"/",
".", or "-" can also be inserted between the letters to add
additional formatting:
Definition and Usage
The date_default_timezone_set() function sets
the default timezone used by all date/time functions in the script.
date_default_timezone_set("Africa/Cairo");
<?php
echo date("Y/m/d") . "<br>";
echo date("Y.m.d") . "<br>";
echo date("Y-m-d");
?>
echo date("Y/m/d") . "<br>";
echo date("Y.m.d") . "<br>";
echo date("Y-m-d");
?>
PHP Date() - Adding a
Timestamp
The optional timestamp parameter
in the date() function specifies a timestamp. If you do not specify a
timestamp, the current date and time will be used. The mktime() function
returns the Unix timestamp for a date.
The Unix timestamp contains the number of
seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time
specified.
Syntax for mktime()
mktime(hour,minute,second,month,day,year,is_dst)
To go one day in the future we simply add one to
the day argument of mktime():
<?php
$tomorrow =
mktime(0,0,0,date("m"),date("d")+1,date("Y"));
echo "Tomorrow is
".date("Y/m/d", $tomorrow);
?>
The date/time functions allow you to get the
date and time from the server where your PHP script runs. You can then use the
date/time functions to format the date and time in several ways.
Note: These functions depend on the locale settings of your
server.
Runtime
Configuration: The
behavior of these functions is affected by settings in php.ini:
Name
|
Description
|
Default
|
PHP Version
|
date.timezone
|
The default timezone (used by all date/time functions)
|
""
|
PHP 5.1
|
date.default_latitude
|
The default latitude (used by date_sunrise() and date_sunset())
|
"31.7667"
|
PHP 5.0
|
date.default_longitude
|
The default longitude (used by date_sunrise() and
date_sunset())
|
"35.2333"
|
PHP 5.0
|
date.sunrise_zenith
|
The default sunrise zenith (used by date_sunrise() and
date_sunset())
|
"90.83"
|
PHP 5.0
|
date.sunset_zenith
|
The default sunset zenith (used by date_sunrise() and
date_sunset())
|
"90.83"
|
PHP 5.0
|
PHP 5 Date/Time
Functions
Function
|
Description
|
Validates a Gregorian date Syntax: checkdate(month,day,year);
|
|
Adds days, months, years, hours, minutes, and seconds to a
date
$date=date_create("2013-03-15");
date_add($date,date_interval_create_from_date_string("40
days"));
echo date_format($date,"Y-m-d");
|
|
Returns a new DateTime object formatted according to a
specified format
|
|
Returns a new DateTime object
|
|
Sets a new date $date=date_create();
date_date_set($date,2020,10,30);
echo date_format($date,"Y/m/d");
|
|
Returns the default timezone used by all date/time
functions
echo
date_default_timezone_get();
|
|
Sets the default timezone used by all date/time functions
|
|
Returns the difference between two dates
$date1=date_create("2013-03-15"); $date2=date_create("2013-12-12");
$diff=date_diff($date1,$date2);
|
|
Returns a date formatted according to a specified format
|
|
Returns the warnings/errors found in a date string
|
|
date_interval_create_from_date_string()
|
Sets up a DateInterval from the relative parts of the
string
|
Formats the interval
$date1=date_create("2013-01-01"); $date2=date_create("2013-02-10");
$diff=date_diff($date1,$date2);
// %a outputs the total number of days
echo $diff->format("Total number of days:
%a."); result: Month: 1, days: 9.
|
|
Sets the ISO date
|
|
Modifies the timestamp
$date=date_create("2013-05-01");
date_modify($date,"+15 days");
echo
date_format($date,"Y-m-d"); result: 2013-05-16
|
|
Returns the timezone offset
|
|
Returns an associative array with detailed info about a
specified date, according to a specified format
|
|
Returns an associative array with detailed info about a
specified date
|
|
Subtracts days, months, years, hours, minutes, and seconds
from a date
|
|
Returns an array containing info about sunset/sunrise and
twilight begin/end, for a specified day and location
|
|
Returns the sunrise time for a specified day and location
echo(date_sunrise(time(),SUNFUNCS_RET_STRING,2));
|
|
Returns the sunset time for a specified day and location
|
|
Sets the time
|
|
Returns the Unix
timestamp echo date_timestamp_get($date);
|
|
Sets the date and time based on a Unix timestamp
|
|
Returns the time zone of the given DateTime object
|
|
Sets the time zone for the DateTime object
|
|
Formats a local date and time
|
|
Returns date/time information of a timestamp or the
current local date/time
|
|
Returns the current time
|
|
Formats a GMT/UTC date and time
|
|
Returns the Unix timestamp for a GMT date
|
|
Formats a GMT/UTC date and time according to locale
settings
|
|
Formats a local time/date as integer
|
|
Returns the local time
|
|
Returns the current Unix timestamp with microseconds
|
|
Returns the Unix timestamp for a date
|
|
Formats a local time and/or date according to locale settings
|
|
Parses a time/date generated with strftime()
|
|
Parses an English textual datetime into a Unix timestamp
|
|
Returns the current time as a Unix timestamp
|
|
Returns an associative array containing dst, offset, and
the timezone name
|
|
Returns an indexed array with all timezone identifiers
|
|
Returns location information for a specified timezone
|
|
Returns the timezone name from abbreviation
|
|
Returns the name of the timezone
|
|
Returns the timezone offset from GMT
|
|
Creates new DateTimeZone object
|
|
timezone_transitions_get()
|
Returns all transitions for the timezone
|
Returns the version of the timezone db
|
PHP 5 Predefined
Date/Time Constants
Constant
|
Description
|
DATE_ATOM
|
Atom (example: 2005-08-15T16:13:03+0000)
|
DATE_COOKIE
|
HTTP Cookies (example: Sun, 14 Aug 2005 16:13:03 UTC)
|
DATE_ISO8601
|
ISO-8601 (example: 2005-08-14T16:13:03+0000)
|
DATE_RFC822
|
RFC 822 (example: Sun, 14 Aug 2005 16:13:03 UTC)
|
DATE_RFC850
|
RFC 850 (example: Sunday, 14-Aug-05 16:13:03 UTC)
|
DATE_RFC1036
|
RFC 1036 (example: Sunday, 14-Aug-05 16:13:03 UTC)
|
DATE_RFC1123
|
RFC 1123 (example: Sun, 14 Aug 2005 16:13:03 UTC)
|
DATE_RFC2822
|
RFC 2822 (Sun, 14 Aug 2005 16:13:03 +0000)
|
DATE_RSS
|
RSS (Sun, 14 Aug 2005 16:13:03 UTC)
|
DATE_W3C
|
World Wide Web Consortium (example:
2005-08-14T16:13:03+0000)
|
PHP include and require Statements
In PHP, you can insert the content of one PHP
file into another PHP file before the server executes it.
Include and require are identical, except upon
failure:
- require
will produce a fatal error (E_COMPILE_ERROR) and stop the script
- include
will only produce a warning (E_WARNING) and the script will continue
So, if you want the execution to go on and show
users the output, even if the include file is missing, use include. Otherwise,
in case of FrameWork, CMS or a complex PHP application coding, always use
require to include a key file to the flow of execution. This will help avoid
compromising your application's security and integrity, just in-case one key
file is accidentally missing.
Including files saves a lot of work. This means
that you can create a standard header, footer, or menu file for all your web
pages. Then, when the header needs to be updated, you can only update the
header include file.
Syntax
include 'filename'; or require
'filename';
Assume that you have a standard header file,
called "header.php". To include the header file in a page, use
include/require:
<?php include 'header.php'; ?>
<h1>Welcome to my home page!</h1>
<p>Some text.</p>
Assume we have a standard menu file that should
be used on all pages. "menu.php":
echo '<a
href="/default.php">Home</a>
<a
href="/tutorials.php">Tutorials</a>
<a
href="/references.php">References</a>
<a
href="/examples.php">Examples</a>
<a href="/about.php">About
Us</a>
<a href="/contact.php">Contact
Us</a>';
|
<html>
<body>
<div class="leftmenu">
<?php include 'menu.php'; ?>
</div>
<h1>Welcome to my home page.</h1>
<p>Some text.</p>
</body>
</html>
<body>
<div class="leftmenu">
<?php include 'menu.php'; ?>
</div>
<h1>Welcome to my home page.</h1>
<p>Some text.</p>
</body>
</html>
Assume we have an include file with some
variables defined ("vars.php"):
<?php
$color='red';
$car='BMW';
?>
Then the variables can be used in the calling
file:
<html>
<body>
<h1>Welcome to my home page.</h1>
<?php include 'vars.php';
echo "I have a $color $car"; // I have
a red BMW
?>
</body>
</html>
PHP File Handling
The fopen() function is used to open files in
PHP.
The first parameter of this function contains
the name of the file to be opened and the second parameter specifies in which
mode the file should be opened:
<?php
$file=fopen("welcome.txt","r") or exit("Unable to open file!");
?>
$file=fopen("welcome.txt","r") or exit("Unable to open file!");
?>
Modes
|
Description
|
r
|
Read only. Starts at the beginning of the file
|
r+
|
Read/Write. Starts at the beginning of the file
|
w
|
Write only. Opens and clears the contents of file; or
creates a new file if it doesn't exist
|
w+
|
Read/Write. Opens and clears the contents of file; or
creates a new file if it doesn't exist
|
a
|
Append. Opens and writes to the end of the file or creates
a new file if it doesn't exist
|
a+
|
Read/Append. Preserves file content by writing to the end
of the file
|
x
|
Write only. Creates a new file. Returns FALSE and an error
if file already exists
|
x+
|
Read/Write. Creates a new file. Returns FALSE and an error
if file already exists
|
|
<?php
$file = fopen("test.txt","r");
//some code to be executed
fclose($file);
?>
$file = fopen("test.txt","r");
//some code to be executed
fclose($file);
?>
Check End-of-file
The feof() function checks if the
"end-of-file" (EOF) has been reached, useful for looping through data
of unknown length.
Note: You cannot read from files opened in w, a, and x
mode! if (feof($file)) echo "End of file";
<?php
$file = fopen("welcome.txt", "r") or exit("Unable to open file!");
//Output a line of the file until the end is reached
while(!feof($file))
{
echo fgets($file). "<br>";
}
fclose($file);
?>
$file = fopen("welcome.txt", "r") or exit("Unable to open file!");
//Output a line of the file until the end is reached
while(!feof($file))
{
echo fgets($file). "<br>";
}
fclose($file);
?>
The example below reads a file character by
character, until the end of file is reached:
<?php
$file=fopen("welcome.txt","r")
or exit("Unable to open file!");
while (!feof($file))
{
echo fgetc($file);
}
fclose($file);
?>
PHP File Upload
<body>
<form action="upload_file.php" method="post"
enctype="multipart/form-data">
<label for="file">Filename:</label>
<input type="file" name="file" id="file"><br>
<input type="submit" name="submit" value="Submit">
</form></body>
<form action="upload_file.php" method="post"
enctype="multipart/form-data">
<label for="file">Filename:</label>
<input type="file" name="file" id="file"><br>
<input type="submit" name="submit" value="Submit">
</form></body>
|
|
<?php
if ($_FILES["file"]["error"] > 0)
{
echo "Error: " . $_FILES["file"]["error"] . "<br>";
} else {
echo "Upload: " . $_FILES["file"]["name"] . "<br>";
echo "Type: " . $_FILES["file"]["type"] . "<br>";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
echo "Stored in: " . $_FILES["file"]["tmp_name"];
}
?>
if ($_FILES["file"]["error"] > 0)
{
echo "Error: " . $_FILES["file"]["error"] . "<br>";
} else {
echo "Upload: " . $_FILES["file"]["name"] . "<br>";
echo "Type: " . $_FILES["file"]["type"] . "<br>";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
echo "Stored in: " . $_FILES["file"]["tmp_name"];
}
?>
<?php
$allowedExts = array("gif", "jpeg", "jpg", "png");
$temp = explode(".", $_FILES["file"]["name"]);
$extension = end($temp);
if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/png"))
&& ($_FILES["file"]["size"] < 20000)
&& in_array($extension, $allowedExts))
{
if ($_FILES["file"]["error"] > 0)
{
echo "Return Code: " . $_FILES["file"]["error"] . "<br>";
} else {
echo "Upload: " . $_FILES["file"]["name"] . "<br>";
echo "Type: " . $_FILES["file"]["type"] . "<br>";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br>";
if (file_exists("upload/" . $_FILES["file"]["name"]))
{
echo $_FILES["file"]["name"] . " already exists. ";
} else {
move_uploaded_file($_FILES["file"]["tmp_name"],
"upload/" . $_FILES["file"]["name"]);
echo "Stored in: " . "upload/" . $_FILES["file"]["name"];
}
}
} else {
echo "Invalid file";
}
?>
$allowedExts = array("gif", "jpeg", "jpg", "png");
$temp = explode(".", $_FILES["file"]["name"]);
$extension = end($temp);
if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/png"))
&& ($_FILES["file"]["size"] < 20000)
&& in_array($extension, $allowedExts))
{
if ($_FILES["file"]["error"] > 0)
{
echo "Return Code: " . $_FILES["file"]["error"] . "<br>";
} else {
echo "Upload: " . $_FILES["file"]["name"] . "<br>";
echo "Type: " . $_FILES["file"]["type"] . "<br>";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br>";
if (file_exists("upload/" . $_FILES["file"]["name"]))
{
echo $_FILES["file"]["name"] . " already exists. ";
} else {
move_uploaded_file($_FILES["file"]["tmp_name"],
"upload/" . $_FILES["file"]["name"]);
echo "Stored in: " . "upload/" . $_FILES["file"]["name"];
}
}
} else {
echo "Invalid file";
}
?>
PHP Cookies
A cookie is often used to identify a user. A
cookie is a small file that the server embeds on the user's computer. Each time
the same computer requests a page with a browser, it will send the cookie too.
With PHP, you can both create and retrieve cookie values.
How to Create a Cookie? The setcookie() function is used to set a cookie. setcookie(name,
value, expire, path, domain);
Note: The setcookie() function must appear BEFORE the <html>
tag.
Example 1
In the example below, we will create a cookie named
"user" and assign the value "Alex Porter" to it. We also
specify that the cookie should expire after one hour:
<?php
setcookie("user", "Alex Porter", time()+3600); ?> <html>
Note: The
value of the cookie is automatically URLencoded when sending the cookie, and
automatically decoded when received (to prevent URLencoding, use
setrawcookie() instead).
|
Example 2
You can also set the expiration time of the cookie in
another way. It may be easier than using seconds.
<?php
$expire=time()+60*60*24*30;
setcookie("user", "Alex Porter",
$expire);
?>
<html>
.....
In the example above the expiration time is set to a month
(60 sec * 60 min * 24 hours * 30 days).
|
<?php
echo $_COOKIE["user"]; // Print a cookie
print_r($_COOKIE); // A way to view all cookies
?>
echo $_COOKIE["user"]; // Print a cookie
print_r($_COOKIE); // A way to view all cookies
?>
<html>
<body>
<?php
if (isset($_COOKIE["user"]))
echo "Welcome " . $_COOKIE["user"] . "!<br>";
else
echo "Welcome guest!<br>";
?>
</body>
</html>
<body>
<?php
if (isset($_COOKIE["user"]))
echo "Welcome " . $_COOKIE["user"] . "!<br>";
else
echo "Welcome guest!<br>";
?>
</body>
</html>
<?php
// set the expiration date to one hour ago
setcookie("user", "",
time()-3600);
?>
<html>
<body>
<form action="welcome.php" method="post">
Name: <input type="text" name="name">
Age: <input type="text" name="age">
<input type="submit">
</form>
</body>
</html>
<body>
<form action="welcome.php" method="post">
Name: <input type="text" name="name">
Age: <input type="text" name="age">
<input type="submit">
</form>
</body>
</html>
Retrieve the values in the
"welcome.php" file like this:
<html>
<body>
Welcome <?php echo $_POST["name"];
?>.<br>
You are <?php echo $_POST["age"];
?> years old.
</body>
</html>
PHP Sessions
A PHP session variable is used to store
information about, or change settings for a user session. Session variables
hold information about one single user, and are available to all pages in one
application.
PHP Session Variables
When you are working with an application, you
open it, do some changes and then you close it. This is much like a Session.
The computer knows who you are. It knows when you start the application and
when you end. But on the internet there is one problem: the web server does not
know who you are and what you do because the HTTP address doesn't maintain
state. A PHP session solves this problem by allowing you to store user
information on the server for later use (i.e. username, shopping items, etc).
However, session information is temporary and will be deleted after the user
has left the website. If you need a permanent storage you may want to store the
data in a database.
Sessions work by creating a unique id (UID) for
each visitor and store variables based on this UID. The UID is either stored in
a cookie or is propagated in the URL.
<?php session_start(); ?>
<html>
<body>
</body>
</html>
<html>
<body>
</body>
</html>
The code above will register the user's session
with the server, allow you to start saving user information, and assign a UID
for that user's session.
<?php
session_start();
// store session data
$_SESSION['views']=1;
?>
<html>
<body>
<?php
echo "Pageviews=". $_SESSION['views']; //retrieve session data
?>
</body>
</html>
session_start();
// store session data
$_SESSION['views']=1;
?>
<html>
<body>
<?php
echo "Pageviews=". $_SESSION['views']; //retrieve session data
?>
</body>
</html>
<?php
session_start();
if(isset($_SESSION['views']))
$_SESSION['views']=$_SESSION['views']+1;
else
$_SESSION['views']=1;
echo "Views=". $_SESSION['views'];
?>
<?php
session_start();
if(isset($_SESSION['views']))
unset($_SESSION['views']);
?>
session_start();
if(isset($_SESSION['views']))
unset($_SESSION['views']);
?>
You can also completely destroy the session by
calling the session_destroy() function:
<?php
session_destroy();
?>
session_destroy();
?>
Note: session_destroy() will reset your session and you will lose
all your stored session data.
PHP Sending E-mails
PHP allows you to send e-mails directly from a
script.
The PHP mail()
Function: mail(to,subject,message,headers,parameters)
Parameter
|
Description
|
to
|
Required. Specifies the receiver/receivers of the email
|
subject
|
Required. Specifies the subject of the email. Note: This
parameter cannot contain any newline characters
|
message
|
Required message sent. Each line should be separated with
a LF (\n). Lines should not exceed 70 characters
|
headers
|
Optional. Specifies additional headers, like From, Cc, and
Bcc. The additional headers should be separated with a CRLF (\r\n)
|
parameters
|
Optional. Specifies an additional parameter to the
sendmail program
|
Note: For the mail functions to be available, PHP requires an
installed and working email system. The program to be used is defined by the
configuration settings in the php.ini file.
<?php
$to = "someone@example.com";
$subject = "Test mail";
$message = "Hello! This is a simple email message.";
$from = "someonelse@example.com";
$headers = "From:" . $from;
mail($to,$subject,$message,$headers);
echo "Mail Sent.";
?>
$to = "someone@example.com";
$subject = "Test mail";
$message = "Hello! This is a simple email message.";
$from = "someonelse@example.com";
$headers = "From:" . $from;
mail($to,$subject,$message,$headers);
echo "Mail Sent.";
?>
PHP Mail Form
<html>
<body>
<?php
if (isset($_REQUEST['email'])) //if "email" is filled out, send email
{
$email = $_REQUEST['email'] ; //send email
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", $subject,
$message, "From:" . $email);
echo "Thank you for using our mail form";
} else { //if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text'><br>
Subject: <input name='subject' type='text'><br>
Message:<br>
<textarea name='message' rows='15' cols='40'>
</textarea><br>
<input type='submit'>
</form>";
}
?>
</body>
</html>
<body>
<?php
if (isset($_REQUEST['email'])) //if "email" is filled out, send email
{
$email = $_REQUEST['email'] ; //send email
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", $subject,
$message, "From:" . $email);
echo "Thank you for using our mail form";
} else { //if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text'><br>
Subject: <input name='subject' type='text'><br>
Message:<br>
<textarea name='message' rows='15' cols='40'>
</textarea><br>
<input type='submit'>
</form>";
}
?>
</body>
</html>
PHP Mail Introduction
The mail() function allows you to send emails
directly from a script.
Requirements:For the mail functions to be available, PHP
requires an installed and working email system. The program to be used is
defined by the configuration settings in the php.ini file.InstallationThe mail
functions are part of the PHP core. There is no installation needed to use
these functions.
Runtime ConfigurationThe behavior of the mail functions is affected by settings in the
php.ini file. Mail configuration options:
Name
|
Default
|
Description
|
Changeable
|
SMTP
|
"localhost"
|
Windows only: The DNS name or IP address of the SMTP
server
|
PHP_INI_ALL
|
smtp_port
|
"25"
|
Windows only: The SMTP port number. Available since PHP
4.3
|
PHP_INI_ALL
|
sendmail_from
|
NULL
|
Windows only: Specifies the "from" address to be
used in email sent from PHP
|
PHP_INI_ALL
|
sendmail_path
|
NULL
|
Unix systems only: Specifies where the sendmail program
can be found (usually /usr/sbin/sendmail or /usr/lib/sendmail)
|
PHP_INI_SYSTEM
|
PHP: indicates the earliest version of PHP that supports the
function.
Function
|
Description
|
PHP
|
ezmlm_hash()
|
Calculates the hash value needed by the EZMLM mailing list
system
|
3
|
Allows you to send emails directly from a script
|
3
|
<html>
<body>
<?php
if (isset($_REQUEST['email']))
//if "email" is filled out, send email
{
//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
}
else
//if "email" is not filled out, display the form
{
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text'><br>
Subject: <input name='subject' type='text'><br>
Message:<br>
<textarea name='message' rows='15' cols='40'>
</textarea><br>
<input type='submit'>
</form>";
}
?>
</body>
</html>
<body>
<?php
if (isset($_REQUEST['email']))
//if "email" is filled out, send email
{
//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
}
else
//if "email" is not filled out, display the form
{
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text'><br>
Subject: <input name='subject' type='text'><br>
Message:<br>
<textarea name='message' rows='15' cols='40'>
</textarea><br>
<input type='submit'>
</form>";
}
?>
</body>
</html>
PHP Stopping E-mail
Injections
<html>
<body>
<?php
function spamcheck($field)
{
//filter_var() sanitizes the e-mail
//address using FILTER_SANITIZE_EMAIL
$field=filter_var($field, FILTER_SANITIZE_EMAIL);
//filter_var() validates the e-mail
//address using FILTER_VALIDATE_EMAIL
if(filter_var($field, FILTER_VALIDATE_EMAIL))
{
return TRUE;
}
else
{
return FALSE;
}
}
if (isset($_REQUEST['email']))
{//if "email" is filled out, proceed
//check if the email address is invalid
$mailcheck = spamcheck($_REQUEST['email']);
if ($mailcheck==FALSE)
{
echo "Invalid input";
}
else
{//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
}
} else {//if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text'><br>
Subject: <input name='subject' type='text'><br>
Message:<br>
<textarea name='message' rows='15' cols='40'>
</textarea><br>
<input type='submit'>
</form>";
}
?>
</body>
</html>
<body>
<?php
function spamcheck($field)
{
//filter_var() sanitizes the e-mail
//address using FILTER_SANITIZE_EMAIL
$field=filter_var($field, FILTER_SANITIZE_EMAIL);
//filter_var() validates the e-mail
//address using FILTER_VALIDATE_EMAIL
if(filter_var($field, FILTER_VALIDATE_EMAIL))
{
return TRUE;
}
else
{
return FALSE;
}
}
if (isset($_REQUEST['email']))
{//if "email" is filled out, proceed
//check if the email address is invalid
$mailcheck = spamcheck($_REQUEST['email']);
if ($mailcheck==FALSE)
{
echo "Invalid input";
}
else
{//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
}
} else {//if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text'><br>
Subject: <input name='subject' type='text'><br>
Message:<br>
<textarea name='message' rows='15' cols='40'>
</textarea><br>
<input type='submit'>
</form>";
}
?>
</body>
</html>
PHP Secure E-mails
<html>
<body>
<?php
if (isset($_REQUEST['email'])) //if "email" is filled out, send email
{
//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
} else { //if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text'><br>
Subject: <input name='subject' type='text'><br>
Message:<br>
<textarea name='message' rows='15' cols='40'>
</textarea><br>
<input type='submit'>
</form>";
}
?>
</body>
</html>
<body>
<?php
if (isset($_REQUEST['email'])) //if "email" is filled out, send email
{
//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
} else { //if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text'><br>
Subject: <input name='subject' type='text'><br>
Message:<br>
<textarea name='message' rows='15' cols='40'>
</textarea><br>
<input type='submit'>
</form>";
}
?>
</body>
</html>
PHP Stopping E-mail
Injections
<body>
<?php
function spamcheck($field)
{
//filter_var() sanitizes the e-mail address using FILTER_SANITIZE_EMAIL
<?php
function spamcheck($field)
{
//filter_var() sanitizes the e-mail address using FILTER_SANITIZE_EMAIL
$field=filter_var($field,
FILTER_SANITIZE_EMAIL);
//filter_var() validates the e-mail address using FILTER_VALIDATE_EMAIL
//filter_var() validates the e-mail address using FILTER_VALIDATE_EMAIL
if(filter_var($field,
FILTER_VALIDATE_EMAIL))
{
return TRUE;
} else {
return FALSE;
}
}
if (isset($_REQUEST['email']))
{ //if "email" is filled out, proceed check if the email address is invalid
{
return TRUE;
} else {
return FALSE;
}
}
if (isset($_REQUEST['email']))
{ //if "email" is filled out, proceed check if the email address is invalid
$mailcheck =
spamcheck($_REQUEST['email']);
if ($mailcheck==FALSE)
{
echo "Invalid input";
} else { //send email
if ($mailcheck==FALSE)
{
echo "Invalid input";
} else { //send email
$email =
$_REQUEST['email'] ; $subject = $_REQUEST['subject']
; $message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
}
} else { //if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text'><br>
Subject: <input name='subject' type='text'><br>
Message:<br>
<textarea name='message' rows='15' cols='40'> </textarea><br>
<input type='submit'>
</form>";
}
?>
</body>
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
}
} else { //if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text'><br>
Subject: <input name='subject' type='text'><br>
Message:<br>
<textarea name='message' rows='15' cols='40'> </textarea><br>
<input type='submit'>
</form>";
}
?>
</body>
PHP Error Handling
The default error handling in PHP is very
simple. An error message with filename, line number and a message describing
the error is sent to the browser. When creating scripts and web applications,
error handling is an important part. If your code lacks error checking code,
your program may look very unprofessional and you may be open to security
risks. Simple "die()"
statements - Custom errors and
error triggers - Error reporting
Basic Error Handling:
Using the die() function
The first example shows a simple script that
opens a text file:
<?php
$file=fopen("welcome.txt","r");
?>
$file=fopen("welcome.txt","r");
?>
|
<?php
if(!file_exists("welcome.txt"))
{
die("File not found");
}
else
{
$file=fopen("welcome.txt","r");
}
?>
if(!file_exists("welcome.txt"))
{
die("File not found");
}
else
{
$file=fopen("welcome.txt","r");
}
?>
The code above is more efficient than the
earlier code, because it uses a simple error handling mechanism to stop the
script after the error. However, simply stopping the script is not always the
right way to go. Let's take a look at alternative PHP functions for handling
errors.
Creating a Custom Error
Handler
Create a special function that can be called
when an error occurs in PHP. This function must be able to handle a minimum of
two parameters (error level and error message) but can accept up to five
parameters.
Syntax: error_function(error_level,error_message,error_file,error_line,error_context)
Parameter
|
Description
|
error_level
|
Required. Specifies the error report level for the
user-defined error. Must be a value number. See table below for
possible error report levels
|
error_message
|
Required. Specifies the error message for the user-defined
error
|
error_file
|
Optional. Specifies the filename in which the error
occurred
|
error_line
|
Optional. Specifies the line number in which the error
occurred
|
error_context
|
Optional. Specifies an array containing every variable,
and their values, in use when the error occurred
|
Error Report levels: These error report levels are the different types of error the
user-defined error handler can be used for:
Value
|
Constant
|
Description
|
2
|
E_WARNING
|
Non-fatal run-time errors. Execution of the script is not
halted
|
8
|
E_NOTICE
|
Run-time notices. The script found something that might be
an error, but could also happen when running a script normally
|
256
|
E_USER_ERROR
|
Fatal user-generated error. This is like an E_ERROR set by
the programmer using the PHP function trigger_error()
|
512
|
E_USER_WARNING
|
Non-fatal user-generated warning. This is like an
E_WARNING set by the programmer using the PHP function trigger_error()
|
1024
|
E_USER_NOTICE
|
User-generated notice. This is like an E_NOTICE set by the
programmer using the PHP function trigger_error()
|
4096
|
E_RECOVERABLE_ERROR
|
Catchable fatal error. This is like an E_ERROR but can be
caught by a user defined handle (see also set_error_handler())
|
8191
|
E_ALL
|
All errors and warnings (E_STRICT became a part of E_ALL
in PHP 5.4)
|
|
<?php
//error handler function
function customError($errno, $errstr)
{
echo "<b>Error:</b> [$errno] $errstr";
}
//set error handler
set_error_handler("customError");
//trigger error
echo($test);
?>
//error handler function
function customError($errno, $errstr)
{
echo "<b>Error:</b> [$errno] $errstr";
}
//set error handler
set_error_handler("customError");
//trigger error
echo($test);
?>
Trigger an Error: In a script where users
can input data it is useful to trigger errors when an illegal input occurs. In
PHP, this is done by the trigger_error() function.
|
<?php
$test=2;
if ($test>1)
{
trigger_error("Value must be 1 or below");
}
?>
$test=2;
if ($test>1)
{
trigger_error("Value must be 1 or below");
}
?>
· E_USER_ERROR - Fatal user-generated run-time
error. Errors that can not be recovered from. Execution of the script is halted
· E_USER_WARNING - Non-fatal user-generated
run-time warning. Execution of the script is not halted
· E_USER_NOTICE - Default. User-generated run-time
notice. The script found something that might be an error, but could also
happen when running a script normally
|
<?php
function customError($errno, $errstr)
{
echo "<b>Error:</b> [$errno] $errstr<br>";
echo "Ending Script";
die();
} //set error handler
set_error_handler("customError",E_USER_WARNING);
$test=2;
if ($test>1)
{ trigger_error("Value must be 1 or below",E_USER_WARNING);}
?>
function customError($errno, $errstr)
{
echo "<b>Error:</b> [$errno] $errstr<br>";
echo "Ending Script";
die();
} //set error handler
set_error_handler("customError",E_USER_WARNING);
$test=2;
if ($test>1)
{ trigger_error("Value must be 1 or below",E_USER_WARNING);}
?>
Error Logging
By default, PHP sends an error log to the
server's logging system or a file, depending on how the error_log configuration
is set in the php.ini file. By using the error_log() function you can send
error logs to a specified file or a remote destination. Sending error messages
to yourself by e-mail can be a good way of getting notified of specific errors.
Send an Error Message by
E-Mail
|
<?php
//error handler function
function customError($errno, $errstr)
{
echo "<b>Error:</b> [$errno] $errstr<br>";
echo "Webmaster has been notified";
error_log("Error: [$errno] $errstr",1,
"someone@example.com","From: webmaster@example.com");
} //set error handler
set_error_handler("customError",E_USER_WARNING);
$test=2; //trigger error
if ($test>1)
{ trigger_error("Value must be 1 or below",E_USER_WARNING); }
?>
//error handler function
function customError($errno, $errstr)
{
echo "<b>Error:</b> [$errno] $errstr<br>";
echo "Webmaster has been notified";
error_log("Error: [$errno] $errstr",1,
"someone@example.com","From: webmaster@example.com");
} //set error handler
set_error_handler("customError",E_USER_WARNING);
$test=2; //trigger error
if ($test>1)
{ trigger_error("Value must be 1 or below",E_USER_WARNING); }
?>
PHP Exception
Handling
Exceptions are used to change the normal flow of
a script if a specified error occurs.
What is an Exception
With PHP 5 came a new object oriented way of
dealing with errors. Exception handling is used to change the normal flow of
the code execution if a specified error (exceptional) condition occurs. This
condition is called an exception.
This is what normally happens when an exception
is triggered:
- The
current code state is saved
- The
code execution will switch to a predefined (custom) exception handler
function
- Depending
on the situation, the handler may then resume the execution from the saved
code state, terminate the script execution or continue the script from a
different location in the code
Note: Exceptions should only be used with error
conditions, and should not be used to jump to another place in the code at a
specified point.
Basic Use of Exceptions
|
<?php
//create function with an exception
function checkNum($number)
{
if($number>1)
{throw new Exception("Value must be 1 or below");}
return true;
}
//trigger exception
checkNum(2);
?>
//create function with an exception
function checkNum($number)
{
if($number>1)
{throw new Exception("Value must be 1 or below");}
return true;
}
//trigger exception
checkNum(2);
?>
|
Try, throw and catch
<?php
//create function with an exception
function checkNum($number)
{
if($number>1)
{
throw new Exception("Value must be 1 or below");
}
return true;
}
//trigger exception in a "try" block
try
{
checkNum(2);
//If the exception is thrown, this text will not be shown
echo 'If you see this, the number is 1 or below';
}
//catch exception
catch(Exception $e)
{
echo 'Message: ' .$e->getMessage();
}
?>
//create function with an exception
function checkNum($number)
{
if($number>1)
{
throw new Exception("Value must be 1 or below");
}
return true;
}
//trigger exception in a "try" block
try
{
checkNum(2);
//If the exception is thrown, this text will not be shown
echo 'If you see this, the number is 1 or below';
}
//catch exception
catch(Exception $e)
{
echo 'Message: ' .$e->getMessage();
}
?>
|
reating a Custom Exception Class
|
<?php
class customException extends Exception
{
public function errorMessage()
{
//error message
$errorMsg = 'Error on line '.$this->getLine().' in '.$this->getFile()
.': <b>'.$this->getMessage().'</b> is not a valid E-Mail address';
return $errorMsg;
}
}
$email = "someone@example...com";
try
{
//check if
if(filter_var($email, FILTER_VALIDATE_EMAIL) === FALSE)
{
//throw exception if email is not valid
throw new customException($email);
}
}
catch (customException $e)
{
//display custom message
echo $e->errorMessage();
}
?>
class customException extends Exception
{
public function errorMessage()
{
//error message
$errorMsg = 'Error on line '.$this->getLine().' in '.$this->getFile()
.': <b>'.$this->getMessage().'</b> is not a valid E-Mail address';
return $errorMsg;
}
}
$email = "someone@example...com";
try
{
//check if
if(filter_var($email, FILTER_VALIDATE_EMAIL) === FALSE)
{
//throw exception if email is not valid
throw new customException($email);
}
}
catch (customException $e)
{
//display custom message
echo $e->errorMessage();
}
?>
Multiple Exceptions
|
<?php
class customException extends Exception
{
public function errorMessage()
{
//error message
$errorMsg = 'Error on line '.$this->getLine().' in '.$this->getFile()
.': <b>'.$this->getMessage().'</b> is not a valid E-Mail address';
return $errorMsg;
}
}
$email = "someone@example.com";
try
{
//check if
if(filter_var($email, FILTER_VALIDATE_EMAIL) === FALSE)
{
//throw exception if email is not valid
throw new customException($email);
}
//check for "example" in mail address
if(strpos($email, "example") !== FALSE)
{
throw new Exception("$email is an example e-mail");
}
}
catch (customException $e)
{
echo $e->errorMessage();
}
catch(Exception $e)
{
echo $e->getMessage();
}
?>
class customException extends Exception
{
public function errorMessage()
{
//error message
$errorMsg = 'Error on line '.$this->getLine().' in '.$this->getFile()
.': <b>'.$this->getMessage().'</b> is not a valid E-Mail address';
return $errorMsg;
}
}
$email = "someone@example.com";
try
{
//check if
if(filter_var($email, FILTER_VALIDATE_EMAIL) === FALSE)
{
//throw exception if email is not valid
throw new customException($email);
}
//check for "example" in mail address
if(strpos($email, "example") !== FALSE)
{
throw new Exception("$email is an example e-mail");
}
}
catch (customException $e)
{
echo $e->errorMessage();
}
catch(Exception $e)
{
echo $e->getMessage();
}
?>
|
Example explained:
|
Re-throwing Exceptions
|
|
|
<?php
class customException extends Exception
{
public function errorMessage()
{ //error message
$errorMsg = $this->getMessage().' is not a valid E-Mail address.';
return $errorMsg;
}
}
$email = "someone@example.com";
try
{
try
{
//check for "example" in mail address
if(strpos($email, "example") !== FALSE)
{
throw new Exception($email); //throw exception if email is not valid
}
}
catch(Exception $e)
{
//re-throw exception
throw new customException($email);
}
}
catch (customException $e)
{
//display custom message
echo $e->errorMessage();
}
?>
class customException extends Exception
{
public function errorMessage()
{ //error message
$errorMsg = $this->getMessage().' is not a valid E-Mail address.';
return $errorMsg;
}
}
$email = "someone@example.com";
try
{
try
{
//check for "example" in mail address
if(strpos($email, "example") !== FALSE)
{
throw new Exception($email); //throw exception if email is not valid
}
}
catch(Exception $e)
{
//re-throw exception
throw new customException($email);
}
}
catch (customException $e)
{
//display custom message
echo $e->errorMessage();
}
?>
|
Set a Top Level
Exception Handler
The set_exception_handler() function sets a
user-defined function to handle all uncaught exceptions.
|
<?php
function myException($exception)
{
echo "<b>Exception:</b> " , $exception->getMessage();
}
set_exception_handler('myException');
throw new Exception('Uncaught Exception occurred');
?>
function myException($exception)
{
echo "<b>Exception:</b> " , $exception->getMessage();
}
set_exception_handler('myException');
throw new Exception('Uncaught Exception occurred');
?>
Rules for exceptions
- Code
may be surrounded in a try block, to help catch potential exceptions
- Each
try block or "throw" must have at least one corresponding catch
block
- Multiple
catch blocks can be used to catch different classes of exceptions
- Exceptions
can be thrown (or re-thrown) in a catch block within a try block
A simple rule: If you throw something, you have
to catch it.
PHP Filter
PHP filters are used to validate and filter data
coming from insecure sources, like user input. To test, validate and filter
user input or custom data is an important part of any web application.
Why use a Filter? Almost all web applications depend on
external input. Usually this comes from a user or another application (like a
web service). By using filters you can be sure your application gets the
correct input type.
What is external data? You should always filter all external
data!
- Input
data from a form – Cookies - Web services data - Server variables -
Database query results
Functions and Filters
- filter_var() - Filters a single variable with a specified
filter
- filter_var_array() - Filter several variables with the same or
different filters
- filter_input - Get one input variable and filter it
- filter_input_array - Get several input variables and filter them
with the same or different filters
|
<?php
$int = 123;
if(!filter_var($int, FILTER_VALIDATE_INT))
{
echo("Integer is not valid");
} else {
echo("Integer is valid");
}
?>
$int = 123;
if(!filter_var($int, FILTER_VALIDATE_INT))
{
echo("Integer is not valid");
} else {
echo("Integer is valid");
}
?>
Validating and
Sanitizing
There are two kinds of filters:
Validating filters:
- Are
used to validate user input
- Strict
format rules (like URL or E-Mail validating)
- Returns
the expected type on success or FALSE on failure
Sanitizing filters:
- Are
used to allow or disallow specified characters in a string
- No
data format rules
- Always
return the string
Options and Flags
|
<?php
$var=300;
$int_options = array(
"options"=>array
(
"min_range"=>0,
"max_range"=>256
)
);
if(!filter_var($var, FILTER_VALIDATE_INT, $int_options))
{
echo("Integer is not valid");
} else {
echo("Integer is valid");
}
?>
$var=300;
$int_options = array(
"options"=>array
(
"min_range"=>0,
"max_range"=>256
)
);
if(!filter_var($var, FILTER_VALIDATE_INT, $int_options))
{
echo("Integer is not valid");
} else {
echo("Integer is valid");
}
?>
Validate Input
|
<?php
if(!filter_has_var(INPUT_GET, "email"))
{
echo("Input type does not exist");
}
else
{
if (!filter_input(INPUT_GET, "email", FILTER_VALIDATE_EMAIL))
{
echo "E-Mail is not valid";
}
else
{
echo "E-Mail is valid";
}
}
?>
if(!filter_has_var(INPUT_GET, "email"))
{
echo("Input type does not exist");
}
else
{
if (!filter_input(INPUT_GET, "email", FILTER_VALIDATE_EMAIL))
{
echo "E-Mail is not valid";
}
else
{
echo "E-Mail is valid";
}
}
?>
|
Example Explained
|
Sanitize Input
<?php
if(!filter_has_var(INPUT_POST, "url"))
{
echo("Input type does not exist");
} else {
$url = filter_input(INPUT_POST,
"url", FILTER_SANITIZE_URL);
}
?>
if(!filter_has_var(INPUT_POST, "url"))
{
echo("Input type does not exist");
} else {
$url = filter_input(INPUT_POST,
"url", FILTER_SANITIZE_URL);
}
?>
Filter Multiple Inputs
|
|
|
<?php
$filters = array
(
"name" => array
(
"filter"=>FILTER_SANITIZE_STRING
),
"age" => array
(
"filter"=>FILTER_VALIDATE_INT,
"options"=>array
(
"min_range"=>1,
"max_range"=>120
)
),
"email"=> FILTER_VALIDATE_EMAIL
);
$result = filter_input_array(INPUT_GET, $filters);
if (!$result["age"])
{
echo("Age must be a number between 1 and 120.<br>");
}
elseif(!$result["email"])
{
echo("E-Mail is not valid.<br>");
} else {
echo("User input is valid");
}
?>
$filters = array
(
"name" => array
(
"filter"=>FILTER_SANITIZE_STRING
),
"age" => array
(
"filter"=>FILTER_VALIDATE_INT,
"options"=>array
(
"min_range"=>1,
"max_range"=>120
)
),
"email"=> FILTER_VALIDATE_EMAIL
);
$result = filter_input_array(INPUT_GET, $filters);
if (!$result["age"])
{
echo("Age must be a number between 1 and 120.<br>");
}
elseif(!$result["email"])
{
echo("E-Mail is not valid.<br>");
} else {
echo("User input is valid");
}
?>
Using Filter Callback
<?php
function convertSpace($string)
{
return str_replace("_", " ", $string);
}
$string = "Peter_is_a_great_guy!";
echo filter_var($string, FILTER_CALLBACK,
array("options"=>"convertSpace"));
?>
function convertSpace($string)
{
return str_replace("_", " ", $string);
}
$string = "Peter_is_a_great_guy!";
echo filter_var($string, FILTER_CALLBACK,
array("options"=>"convertSpace"));
?>
PHP MySQL
Introduction
MySQL is a database system used on the web
|
MySQL is very fast, reliable, and easy to use
|
MySQL is free to download and use
|
MySQL is a database system that runs on a server
|
MySQL supports standard SQL
|
MySQL is developed, distributed, and supported by Oracle
Corporation
|
MySQL is ideal for both small and large applications
|
MySQL compiles on a number of platforms
|
MySQL is named after co-founder Monty Widenius's daughter:
My
|
The data in MySQL is stored in tables. A table
is a collection of related data, and it consists of columns and rows.
PHP + MySQL: PHP
combined with MySQL are cross-platform (you can develop in Windows and serve on
a Unix platform)
Download MySQL Database:
If you don't have a PHP server with a MySQL Database, you can download MySQL
for free here: http://www.mysql.com
Facts About MySQL
Database
One great thing about MySQL is that it can be
scaled down to support embedded database applications. Maybe it is because of
this many people think that MySQL can only handle small and medium-sized
systems. The truth is that MySQL is the de-facto standard database system for
web sites with HUGE volumes of both data and end users (like Friendster, Yahoo,
and Google). Look at http://www.mysql.com/customers/ for an overview of companies using MySQL.
PHP Connect to the MySQL
Server
Use the PHP mysqli_connect() function to open a
new connection to the MySQL server.
Open a Connection to the
MySQL Server
Before we can access data in a database, we must
open a connection to the MySQL server.
In PHP, this is done with the mysqli_connect()
function.
Syntax: mysqli_connect(host,username,password,dbname);
Parameter
|
Description
|
host
|
Optional. Either a host name or an IP address
|
username
|
Optional. The MySQL user name
|
password
|
Optional. The password to log in with
|
Dbname
|
Optional. The default database to be used when performing
queries
|
|
<?php
$con=mysqli_connect("example.com","peter","abc123","my_db"); // Create connection
if (mysqli_connect_errno($con)) // Check connection
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
?>
$con=mysqli_connect("example.com","peter","abc123","my_db"); // Create connection
if (mysqli_connect_errno($con)) // Check connection
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
?>
|
<?php
$con=mysqli_connect("example.com","peter","abc123","my_db");
if (mysqli_connect_errno($con)) // Check connection
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
mysqli_close($con);
?>
$con=mysqli_connect("example.com","peter","abc123","my_db");
if (mysqli_connect_errno($con)) // Check connection
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
mysqli_close($con);
?>
PHP Create
Database and Tables: A database holds one or
more tables.
|
<?php
$con=mysqli_connect("example.com","peter","abc123");
if (mysqli_connect_errno()) // Check connection
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$sql="CREATE DATABASE my_db"; // Create database
if (mysqli_query($con,$sql))
{
echo "Database my_db created successfully";
} else {
echo "Error creating database: " . mysqli_error($con);
}
?>
$con=mysqli_connect("example.com","peter","abc123");
if (mysqli_connect_errno()) // Check connection
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$sql="CREATE DATABASE my_db"; // Create database
if (mysqli_query($con,$sql))
{
echo "Database my_db created successfully";
} else {
echo "Error creating database: " . mysqli_error($con);
}
?>
Create a Table
The CREATE TABLE statement is used to create a
table in MySQL.
|
<?php
$con=mysqli_connect("example.com","peter","abc123","my_db");
if (mysqli_connect_errno()) // Check connection
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
// Create table
$sql="CREATE TABLE Persons(FirstName CHAR(30),LastName CHAR(30),Age INT)";
if (mysqli_query($con,$sql)) // Execute query
{
echo "Table persons created successfully";
} else {
echo "Error creating table: " . mysqli_error($con);
}
?>
$con=mysqli_connect("example.com","peter","abc123","my_db");
if (mysqli_connect_errno()) // Check connection
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
// Create table
$sql="CREATE TABLE Persons(FirstName CHAR(30),LastName CHAR(30),Age INT)";
if (mysqli_query($con,$sql)) // Execute query
{
echo "Table persons created successfully";
} else {
echo "Error creating table: " . mysqli_error($con);
}
?>
Primary Keys and Auto
Increment Fields
A primary key is used to uniquely بشكل
مفرد identify the rows
in a table. Each primary key value must be unique within the table.
Furthermore, the primary key field cannot be null because the database
engine requires a value to locate the record. The following example
sets the PID field as the primary key field. The primary key field is often an
ID number, and is often used with the AUTO_INCREMENT
setting automatically increases the value of the field by 1 each
time a new record is added. To ensure that the primary key field cannot be null,
we must add the NOT NULL setting to the field:
$sql = "CREATE TABLE Persons
(
PID INT NOT NULL AUTO_INCREMENT,
PRIMARY KEY(PID),
FirstName CHAR(15),
LastName CHAR(15),
Age INT
)";
Insert Into Table:
|
<?php
require 'db_conn.php';
require 'db_conn.php';
if (mysqli_connect_errno()) //
Check connection
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
mysqli_query($con,"INSERT INTO Persons (FirstName, LastName, Age)
VALUES ('Peter', 'Griffin',35)");
mysqli_query($con,"INSERT INTO Persons (FirstName, LastName, Age)
VALUES ('Glenn', 'Quagmire',33)");
mysqli_close($con);
?>
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
mysqli_query($con,"INSERT INTO Persons (FirstName, LastName, Age)
VALUES ('Peter', 'Griffin',35)");
mysqli_query($con,"INSERT INTO Persons (FirstName, LastName, Age)
VALUES ('Glenn', 'Quagmire',33)");
mysqli_close($con);
?>
Insert Data From a Form
Into a Database
|
<html>
<body>
<form action="insert.php" method="post">
Firstname: <input type="text" name="firstname">
Lastname: <input type="text" name="lastname">
Age: <input type="text" name="age">
<input type="submit">
</form>
<body>
<form action="insert.php" method="post">
Firstname: <input type="text" name="firstname">
Lastname: <input type="text" name="lastname">
Age: <input type="text" name="age">
<input type="submit">
</form>
</body>
</html>
</html>
|
<?php
$con=mysqli_connect("example.com","peter","abc123","my_db");
if (mysqli_connect_errno()) // Check connection
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
$sql="INSERT INTO Persons (FirstName, LastName, Age)
VALUES
('$_POST[firstname]','$_POST[lastname]','$_POST[age]')";
if (!mysqli_query($con,$sql))
{ die('Error: ' . mysqli_error($con)); }
echo "1 record added";
mysqli_close($con);
?>
$con=mysqli_connect("example.com","peter","abc123","my_db");
if (mysqli_connect_errno()) // Check connection
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
$sql="INSERT INTO Persons (FirstName, LastName, Age)
VALUES
('$_POST[firstname]','$_POST[lastname]','$_POST[age]')";
if (!mysqli_query($con,$sql))
{ die('Error: ' . mysqli_error($con)); }
echo "1 record added";
mysqli_close($con);
?>
|
Example
|
PHP
MySQL Select
<?php
$con=mysqli_connect("example.com","peter","abc123","my_db");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$result = mysqli_query($con,"SELECT * FROM Persons");
while($row = mysqli_fetch_array($result))
{
echo $row['FirstName'] . " " . $row['LastName'];
echo "<br>";
}
mysqli_close($con);
?>
$con=mysqli_connect("example.com","peter","abc123","my_db");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$result = mysqli_query($con,"SELECT * FROM Persons");
while($row = mysqli_fetch_array($result))
{
echo $row['FirstName'] . " " . $row['LastName'];
echo "<br>";
}
mysqli_close($con);
?>
Display the Result in an
HTML Table
|
<?php
$con=mysqli_connect("example.com","peter","abc123","my_db");
if (mysqli_connect_errno())
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
$result = mysqli_query($con,"SELECT * FROM Persons");
echo "<table border='1'>
<tr> <th>Firstname</th> <th>Lastname</th> </tr>";
while($row = mysqli_fetch_array($result))
{
echo "<tr>";
echo "<td>" . $row['FirstName'] . "</td>";
echo "<td>" . $row['LastName'] . "</td>";
echo "</tr>";
}
echo "</table>";
mysqli_close($con);
?>
$con=mysqli_connect("example.com","peter","abc123","my_db");
if (mysqli_connect_errno())
{ echo "Failed to connect to MySQL: " . mysqli_connect_error(); }
$result = mysqli_query($con,"SELECT * FROM Persons");
echo "<table border='1'>
<tr> <th>Firstname</th> <th>Lastname</th> </tr>";
while($row = mysqli_fetch_array($result))
{
echo "<tr>";
echo "<td>" . $row['FirstName'] . "</td>";
echo "<td>" . $row['LastName'] . "</td>";
echo "</tr>";
}
echo "</table>";
mysqli_close($con);
?>
PHP Database
ODBC
ODBC is an Application Programming Interface
(API) that allows you to connect to a data source (e.g. an MS Access database).
Create an ODBC
Connection
With an ODBC connection, you can connect to any
database, on any computer in your network, as long as an ODBC connection is
available.
Here is how to create an ODBC connection to a MS
Access Database:
- Open
the Administrative Tools icon in your Control Panel.
- Double-click
on the Data Sources (ODBC) icon inside.
- Choose
the System DSN tab.
- Click
on Add in the System DSN tab.
- Select
the Microsoft Access Driver. Click Finish.
- In
the next screen, click Select to locate the database.
- Give
the database a Data Source Name (DSN).
- Click OK.
Note that this configuration has to be done on the
computer where your web site is located. If you are running Internet
Information Server (IIS) on your own computer, the instructions above will
work, but if your web site is located on a remote server, you have to have
physical access to that server, or ask your web host to to set up a DSN for you
to use.
Connecting to an ODBC
The odbc_connect() function is used to connect
to an ODBC data source. The function takes four parameters: the data source
name, username, password, and an optional cursor type.
The odbc_exec() function is used to execute an
SQL statement.
|
<html>
<body>
<?php
$conn=odbc_connect('northwind','','');
if (!$conn)
{exit("Connection Failed: " . $conn);}
$sql="SELECT * FROM customers";
$rs=odbc_exec($conn,$sql);
if (!$rs)
{exit("Error in SQL");}
echo "<table><tr>";
echo "<th>Companyname</th>";
echo "<th>Contactname</th></tr>";
while (odbc_fetch_row($rs))
{
$compname=odbc_result($rs,"CompanyName");
$conname=odbc_result($rs,"ContactName");
echo "<tr><td>$compname</td>";
echo "<td>$conname</td></tr>";
}
odbc_close($conn);
echo "</table>";
?>
</body>
</html>
<body>
<?php
$conn=odbc_connect('northwind','','');
if (!$conn)
{exit("Connection Failed: " . $conn);}
$sql="SELECT * FROM customers";
$rs=odbc_exec($conn,$sql);
if (!$rs)
{exit("Error in SQL");}
echo "<table><tr>";
echo "<th>Companyname</th>";
echo "<th>Contactname</th></tr>";
while (odbc_fetch_row($rs))
{
$compname=odbc_result($rs,"CompanyName");
$conname=odbc_result($rs,"ContactName");
echo "<tr><td>$compname</td>";
echo "<td>$conname</td></tr>";
}
odbc_close($conn);
echo "</table>";
?>
</body>
</html>
PHP XML Expat Parser
The built-in Expat parser makes it possible to
process XML documents in PHP.
What is XML? XML is used to describe data and to focus
on what data is. An XML file describes the structure of the data. In XML, no
tags are predefined. You must define your own tags.
What is Expat? Read and update - create and manipulate - an XML document. There
are 2 types of XML parsers:
· Tree-based parser: This parser transforms an XML
document into a tree structure. It analyzes the whole document, and provides
access to the tree elements. e.g. the Document Object Model (DOM)
· Event-based parser: Views an XML document as a
series of events. When a specific event occurs, it calls a function to handle
it
The Expat parser is an event-based parser.
Event-based parsers focus on the content of the XML documents, not their
structure. Because of this, event-based parsers can access data faster than
tree-based parsers. Look at the following XML fraction: <from>Jani</from> An
event-based parser reports the XML above as a series of three events:
· Start element:
from - Start CDATA section, value:
Jani - Close element: from
Example above contains well-formed XML. However,
the example is not valid XML, because there is no Document Type Definition
(DTD) associated with it. However, this makes no difference when using the
Expat parser. Expat is a non-validating parser, and ignores any DTDs. As an
event-based, non-validating XML parser, Expat is fast and small, and a perfect
match for PHP web applications. Note: XML documents must be
well-formed or Expat will generate an error. Installation: The XML Expat parser functions are part of the
PHP core. There is no installation.
An XML File: The XML file below will be used in our
example: Initializing the XML Parser
PHP XML DOM
The built-in DOM parser makes it possible to
process XML documents in PHP.
What is DOM?: The W3C DOM provides a standard set of objects for HTML and XML
documents, and a standard interface for accessing and manipulating them.
The W3C DOM is separated into different parts
(Core, XML, and HTML) and different levels (DOM Level 1/2/3):
- Core
DOM - defines a standard set of objects for any structured document
- XML
DOM - defines a standard set of objects for XML documents
- HTML
DOM - defines a standard set of objects for HTML documents
|
The DOM parser is an tree-based parser. Look at
the following XML document fraction:
<?xml version="1.0"
encoding="ISO-8859-1"?>
<from>Jani</from>
<from>Jani</from>
An XML File
|
The XML file below will be used in our example:
<?xml version="1.0"
encoding="ISO-8859-1"?>
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
<?php
$xmlDoc = new DOMDocument();
$xmlDoc->load("note.xml");
$x = $xmlDoc->documentElement;
foreach ($x->childNodes AS $item)
{
print $item->nodeName . " = "
$xmlDoc = new DOMDocument();
$xmlDoc->load("note.xml");
$x = $xmlDoc->documentElement;
foreach ($x->childNodes AS $item)
{
print $item->nodeName . " = "
.
$item->nodeValue . "<br>";
}
?>
}
?>
|
The output of the code above will be:
#text =
to = Tove
#text =
from = Jani
#text =
heading = Reminder
#text =
body = Don't forget me this weekend!
#text =
to = Tove
#text =
from = Jani
#text =
heading = Reminder
#text =
body = Don't forget me this weekend!
#text =
PHP SimpleXML: PHP SimpleXML handles
the most common XML tasks and leaves the rest for other extensions.
What is PHP
SimpleXML? is new in PHP 5.The
SimpleXML extension provides is a simple way of getting an XML element's name
and text. Compared to DOM or the Expat parser, SimpleXML just takes a few
lines of code to read text data from an XML element. SimpleXML converts the XML document (or XML
string) into an object, like this:
· Elements are converted to single attributes of
the SimpleXMLElement object. When there's more than 1 element on level they are
placed inside an array- Attributes are accessed using associative arrays, where an index corresponds to the attribute name
· Text inside elements is converted to strings. If
an element has more than one text node, they will be arranged in the order they
are found. SimpleXML is fast and easy to use when performing tasks like:
· Reading/Extracting data from XML
files/strings - Editing
text nodes or attributes
<?xml version="1.0"
encoding="ISO-8859-1"?>
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this
weekend!</body>
</note>
Now we want to output different information from
the XML file above:
example 3 will be:
note
to: Tove
from: Jani
heading: Reminder
body: Don't forget me this weekend!
to: Tove
from: Jani
heading: Reminder
body: Don't forget me this weekend!
PHP and AJAX
AJAX Introduction: AJAX is about updating
parts of a web page, without reloading the whole page.
What is AJAX? AJAX = Asynchronous
JavaScript and XML.
AJAX is a technique for creating fast and
dynamic web pages.
AJAX allows update parts of a web page, without
reloading the whole page.
Classic web pages, (which do not use AJAX) must
reload the entire page if the content should change.
Examples of applications using AJAX: Google
Maps, Gmail, Youtube, and Facebook tabs.
How AJAX Works
|
|
|
|
<html>
<head>
<script>
function showHint(str)
{
if (str.length==0)
{
document.getElementById("txtHint").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","gethint.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>
<p><b>Start typing a name in the input field below:</b></p>
<form>
First name: <input type="text" onkeyup="showHint(this.value)">
</form>
<p>Suggestions: <span id="txtHint"></span></p>
</body>
</html>
<head>
<script>
function showHint(str)
{
if (str.length==0)
{
document.getElementById("txtHint").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","gethint.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>
<p><b>Start typing a name in the input field below:</b></p>
<form>
First name: <input type="text" onkeyup="showHint(this.value)">
</form>
<p>Suggestions: <span id="txtHint"></span></p>
</body>
</html>
|
The PHP File
<?php
$a[]="Anna"; // Fill up array with names
$a[]="Brittany";
$a[]="Cinderella";
$a[]="Diana";
$a[]="Eva";
$a[]="Fiona";
$a[]="Gunda";
$a[]="Anna"; // Fill up array with names
$a[]="Brittany";
$a[]="Cinderella";
$a[]="Diana";
$a[]="Eva";
$a[]="Fiona";
$a[]="Gunda";
|
$a[]="Hege";
$a[]="Inga";
$a[]="Johanna";
$a[]="Kitty";
$a[]="Linda";
$a[]="Nina";
$a[]="Ophelia";
$a[]="Petunia";
$a[]="Amanda";
$a[]="Raquel";
$a[]="Cindy";
$a[]="Doris";
$a[]="Eve";
$a[]="Evita";
$a[]="Sunniva";
$a[]="Tove";
$a[]="Unni";
$a[]="Violet";
$a[]="Liza";
$a[]="Elizabeth";
$a[]="Ellen";
$a[]="Wenche";
$a[]="Vicky";
$q=$_GET["q"]; //get the q parameter from URL
if (strlen($q) > 0) //lookup all hints from array if length of q>0
{
$hint="";
for($i=0; $i<count($a); $i++)
{
if (strtolower($q)==strtolower(substr($a[$i],0,strlen($q))))
{
if ($hint=="")
$a[]="Inga";
$a[]="Johanna";
$a[]="Kitty";
$a[]="Linda";
$a[]="Nina";
$a[]="Ophelia";
$a[]="Petunia";
$a[]="Amanda";
$a[]="Raquel";
$a[]="Cindy";
$a[]="Doris";
$a[]="Eve";
$a[]="Evita";
$a[]="Sunniva";
$a[]="Tove";
$a[]="Unni";
$a[]="Violet";
$a[]="Liza";
$a[]="Elizabeth";
$a[]="Ellen";
$a[]="Wenche";
$a[]="Vicky";
$q=$_GET["q"]; //get the q parameter from URL
if (strlen($q) > 0) //lookup all hints from array if length of q>0
{
$hint="";
for($i=0; $i<count($a); $i++)
{
if (strtolower($q)==strtolower(substr($a[$i],0,strlen($q))))
{
if ($hint=="")
{
$hint=$a[$i];
} else { $hint=$hint." , ".$a[$i]; }
}
}
}
if ($hint == "") // Set output to "no suggestion" if no hint were found or to the correct values
{ $response="no suggestion"; } else { $response=$hint; }
echo $response; //output the response
?>
$hint=$a[$i];
} else { $hint=$hint." , ".$a[$i]; }
}
}
}
if ($hint == "") // Set output to "no suggestion" if no hint were found or to the correct values
{ $response="no suggestion"; } else { $response=$hint; }
echo $response; //output the response
?>
PHP
- AJAX and MySQL: AJAX can be used for interactive
communication with a database.
|
Example Explained - The
MySQL Database
|
AJAX Database Example: The following example will demonstrate how a web page can fetch
information from a database with AJAX: Person info will be listed here...
id
|
FirstName
|
LastName
|
Age
|
Hometown
|
Job
|
1
|
Peter
|
Griffin
|
41
|
Quahog
|
Brewery
|
2
|
Lois
|
Griffin
|
40
|
Newport
|
Piano Teacher
|
|
<html>
<head>
<script>
function showUser(str)
{
if (str=="")
{
<head>
<script>
function showUser(str)
{
if (str=="")
{
document.getElementById("txtHint").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
} else {// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","getuser.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
} else {// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","getuser.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>
<form>
<select name="users" onchange="showUser(this.value)">
<option value="">Select a person:</option>
<option value="1">Peter Griffin</option>
<option value="2">Lois Griffin</option>
<option value="3">Glenn Quagmire</option>
<option value="4">Joseph Swanson</option>
</select>
</form>
<br>
<div id="txtHint"><b>Person info will be listed here.</b></div>
</body>
</html>
<select name="users" onchange="showUser(this.value)">
<option value="">Select a person:</option>
<option value="1">Peter Griffin</option>
<option value="2">Lois Griffin</option>
<option value="3">Glenn Quagmire</option>
<option value="4">Joseph Swanson</option>
</select>
</form>
<br>
<div id="txtHint"><b>Person info will be listed here.</b></div>
</body>
</html>
The PHP File
The page on the server called by the JavaScript
above is a PHP file called "getuser.php".
The source code in "getuser.php" runs
a query against a MySQL database, and returns the result in an HTML table:
<?php
$q = intval($_GET['q']);
require 'db_conn.php';
mysqli_select_db($con,"ajax_demo"); // change the database to "ajax_demo"
$sql="SELECT * FROM user WHERE id = '".$q."'";
$result = mysqli_query($con,$sql);
echo "<table border='1'>
<tr>
<th>Firstname</th>
<th>Lastname</th>
<th>Age</th>
<th>Hometown</th>
<th>Job</th>
</tr>";
while($row = mysqli_fetch_array($result))
{
echo "<tr>";
echo "<td>" . $row['FirstName'] . "</td>";
echo "<td>" . $row['LastName'] . "</td>";
echo "<td>" . $row['Age'] . "</td>";
echo "<td>" . $row['Hometown'] . "</td>";
echo "<td>" . $row['Job'] . "</td>";
echo "</tr>";
}
echo "</table>";
mysqli_close($con);
?>
$q = intval($_GET['q']);
require 'db_conn.php';
mysqli_select_db($con,"ajax_demo"); // change the database to "ajax_demo"
$sql="SELECT * FROM user WHERE id = '".$q."'";
$result = mysqli_query($con,$sql);
echo "<table border='1'>
<tr>
<th>Firstname</th>
<th>Lastname</th>
<th>Age</th>
<th>Hometown</th>
<th>Job</th>
</tr>";
while($row = mysqli_fetch_array($result))
{
echo "<tr>";
echo "<td>" . $row['FirstName'] . "</td>";
echo "<td>" . $row['LastName'] . "</td>";
echo "<td>" . $row['Age'] . "</td>";
echo "<td>" . $row['Hometown'] . "</td>";
echo "<td>" . $row['Job'] . "</td>";
echo "</tr>";
}
echo "</table>";
mysqli_close($con);
?>
Explanation: When the query is sent from the
JavaScript to the PHP file, the following happens:
- PHP
opens a connection to a MySQL server
- The
correct person is found
- An
HTML table is created, filled with data, and sent back to the
"txtHint" placeholder
PHP Example - AJAX and XML
AJAX can be used for interactive communication
with an XML file.
AJAX XML Example: The
following example will demonstrate how a web page can fetch information from an
XML file with AJAX:
Example Explained - The HTML Page
When a user selects a CD in the dropdown list
above, a function called "showCD()" is executed. The function is triggered
by the "onchange" event:
<html>
<head>
<script>
function showCD(str)
{
if (str=="")
{
document.getElementById("txtHint").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome,
Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new
ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 &&
xmlhttp.status==200)
{
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","getcd.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>
<form>
Select a CD:
<select name="cds"
onchange="showCD(this.value)">
<option value="">Select a
CD:</option>
<option value="Bob Dylan">Bob
Dylan</option>
<option value="Bonnie
Tyler">Bonnie Tyler</option>
<option value="Dolly
Parton">Dolly Parton</option>
</select>
</form>
<div id="txtHint"><b>CD
info will be listed here...</b></div>
</body>
</html>
The showCD() function does the following:
- Check
if a CD is selected
- Create
an XMLHttpRequest object
- Create
the function to be executed when the server response is ready
- Send
the request off to a file on the server
- Notice
that a parameter (q) is added to the URL (with the content of the dropdown
list)
The PHP File
The page on the server called by the JavaScript
above is a PHP file called "getcd.php".
The PHP script loads an XML document, "cd_catalog.xml",
runs a query against the XML file, and returns the result as HTML:
|
<?php
$q=$_GET["q"];
$xmlDoc = new DOMDocument();
$xmlDoc->load("cd_catalog.xml");
$x=$xmlDoc->getElementsByTagName('ARTIST');
for ($i=0; $i<=$x->length-1; $i++)
{ if ($x->item($i)->nodeType==1) //Process
only element nodes
{
if
($x->item($i)->childNodes->item(0)->nodeValue == $q)
{ $y=($x->item($i)->parentNode); }
}
}
$cd=($y->childNodes);
for ($i=0;$i<$cd->length;$i++)
{
if ($cd->item($i)->nodeType==1) //Process
only element nodes
{
echo("<b>" . $cd->item($i)->nodeName
. ":</b> ");
echo($cd->item($i)->childNodes->item(0)->nodeValue);
echo("<br>");
}
}
?>
PHP Example - AJAX Live Search
The following example will demonstrate a live
search, where you get search results while you type.
Live search has many benefits compared to
traditional searching:
Results are shown as you type - Results narrow
as you continue typing. Search for a W3Schools page in the input field below:
The results in the example above are found in an
XML file (links.xml).To
make this example small and simple, only six results are available.
The HTML Page
When a user types a character in the input field
above, the function "showResult()" is executed. The function is
triggered by the "onkeyup" event:
<html>
<head>
<script>
function showResult(str)
{
if (str.length==0)
{
document.getElementById("livesearch").innerHTML="";
document.getElementById("livesearch").style.border="0px";
return;
}
if (window.XMLHttpRequest)
{ xmlhttp=new XMLHttpRequest();//
code for IE7+, Firefox, Chrome, Opera, Safari
} else { xmlhttp=new
ActiveXObject("Microsoft.XMLHTTP"); // code for IE6, IE5 }
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 &&
xmlhttp.status==200)
{
document.getElementById("livesearch").innerHTML=xmlhttp.responseText;
document.getElementById("livesearch").style.border="1px solid
#A5ACB2";
}
}
xmlhttp.open("GET","livesearch.php?q="+str,true);
xmlhttp.send();
}
</script></head>
<body>
<form>
<input type="text"
size="30" onkeyup="showResult(this.value)">
<div
id="livesearch"></div>
</form></body></html>
|
The PHP File
The page on the server called by the JavaScript
above is a PHP file called "livesearch.php".
The source code in "livesearch.php"
searches an XML file for titles matching the search string and returns the
result:
|
<?php
$xmlDoc=new DOMDocument();
$xmlDoc->load("links.xml");
$x=$xmlDoc->getElementsByTagName('link');
$q=$_GET["q"]; //get the q
parameter from URL
if (strlen($q)>0) //lookup all links from the
xml file if length of q>0
{
$hint="";
for($i=0; $i<($x->length); $i++)
{
$y=$x->item($i)->getElementsByTagName('title');
$z=$x->item($i)->getElementsByTagName('url');
if ($y->item(0)->nodeType==1)
{ //find a link
matching the search text
if
(stristr($y->item(0)->childNodes->item(0)->nodeValue,$q))
{
if
($hint=="")
{
$hint="<a
href='" .
$z->item(0)->childNodes->item(0)->nodeValue
. "' target='_blank'>" .
$y->item(0)->childNodes->item(0)->nodeValue .
"</a>";
} else {
} else {
$hint=$hint
. "<br /><a href='" .
$z->item(0)->childNodes->item(0)->nodeValue
. "' target='_blank'>" .
$y->item(0)->childNodes->item(0)->nodeValue .
"</a>";
}
}
}
}
}// Set output to "no suggestion" if
no hint were found or to the correct values
if ($hint=="")
{ $response="no
suggestion"; }
else { $response=$hint; }
echo $response; //output the response
?>
AJAX
RSS Reader
The following example will demonstrate an RSS
reader, where the RSS-feed is loaded into a webpage without reloading:
Example Explained - The
HTML Page
When a user selects an RSS-feed in the dropdown
list above, a function called "showRSS()" is executed. The function
is triggered by the "onchange" event:
|
<html>
<head>
<script>
function showRSS(str)
{
if (str.length==0)
{
document.getElementById("rssOutput").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{ xmlhttp=new XMLHttpRequest(); } // code for IE7+, Firefox, Chrome, Opera, Safari
else { xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } // code for IE6, IE5
{
if (str.length==0)
{
document.getElementById("rssOutput").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{ xmlhttp=new XMLHttpRequest(); } // code for IE7+, Firefox, Chrome, Opera, Safari
else { xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } // code for IE6, IE5
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 &&
xmlhttp.status==200)
{ document.getElementById("rssOutput").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","getrss.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>
<form>
<select
onchange="showRSS(this.value)">
<option value="">Select an
RSS-feed:</option>
<option value="Google">Google
News</option>
<option value="MSNBC">MSNBC
News</option>
</select>
</form>
<br>
<div id="rssOutput">RSS-feed
will be listed here...</div>
</body>
</html>
The PHP File
The page on the server called by the JavaScript
above is a PHP file called "getrss.php":
<?php
$q=$_GET["q"]; //get the q
parameter from URL
if($q=="Google") //find out which feed
was selected
{
$xml=("http://news.google.com/news?ned=us&topic=h&output=rss"); }
elseif($q=="MSNBC") {
$xml=("http://rss.msnbc.msn.com/id/3032091/device/rss/rss.xml"); }
$xmlDoc = new DOMDocument();
$xmlDoc->load($xml); //get elements from
"<channel>"
$channel=$xmlDoc->getElementsByTagName('channel')->item(0);
$channel_title =
$channel->getElementsByTagName('title')
->item(0)->childNodes->item(0)->nodeValue;
$channel_link =
$channel->getElementsByTagName('link')
->item(0)->childNodes->item(0)->nodeValue;
$channel_desc =
$channel->getElementsByTagName('description')
->item(0)->childNodes->item(0)->nodeValue;
//output elements from
"<channel>"
echo("<p><a href='" .
$channel_link
. "'>" . $channel_title
. "</a>");
echo("<br>");
echo($channel_desc . "</p>");
//get and output "<item>"
elements
$x=$xmlDoc->getElementsByTagName('item');
for ($i=0; $i<=2; $i++)
{
$item_title=$x->item($i)->getElementsByTagName('title')
->item(0)->childNodes->item(0)->nodeValue;
$item_link=$x->item($i)->getElementsByTagName('link')
->item(0)->childNodes->item(0)->nodeValue;
$item_desc=$x->item($i)->getElementsByTagName('description')
->item(0)->childNodes->item(0)->nodeValue;
echo ("<p><a
href='" . $item_link
. "'>" . $item_title .
"</a>");
echo ("<br>");
echo ($item_desc .
"</p>");
}
?>
When a request for an RSS feed is sent from the
JavaScript, the following happens:
- Check
which feed was selected
- Create
a new XML DOM object
- Load
the RSS document in the xml variable
- Extract
and output elements from the channel element
- Extract
and output elements from the item elements
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