PHP SESSION


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PHP SESSION VARIABLE

php tutorial

Session variable is special type of array that holds information for individual user again unique session id like sending information from one web page to another or many pages using unique identity by session id for individual user. It is used to persist state information between page requests.

session variable automatically shut down when PHP is finished executing a script, but manually we can do shut down using session_write_close() function.


Session Variable function's list

FunctionDefinition
session_startIt create a session or resumes the current one based on session id identifier, that passed through GET or POST request.
session_statusReturn current status of session variable.
session_idIt is used to get or set session id to the current session.
session_abortIt discard changes of session array and finish session.
session_destroyIt destroy all data associated with session variable.
session_resetIt re-initialize session variable with original value.
session_registerRegister one or more global variables with the current session.
session_unsetFree all session variable that currently has been registered
session_write_closeIt is used to write session data and end session.

What is $_SESSION in php

$_SESSION is associative array containing session variables available to the current script. We can apply session variable like this.

<?php
						
session_start(); //It should me mention first line of script after php.

$_SESSION['variable_name']=value;
						
?>?>

Destroying php session

A php session can be destroy using session_destroy() function. Single call of this function can destroy all session variable of current running php script.

If we want to destroy single session variable, we can use of unset() function to unset() session variable.

Here example of unset with php session
<?php

unset($_SESSION['counter']);

?>


How to use of session variable in php

Example of php session variable with login page and selecting fruit and display it using session
For example we need to create three .php file
  • ☛ login.php
  • ☛ trap.php
  • ☛ display.php
login.php
<html>

<head<title>Login Page</title></head>

<body>

<form method="post" action="trap.php">

User ID: <input type="text" name="uid"/><br/>

Password:<input type="password" name="pwd"/><br/>

<input type="submit" name="submit" value="Login">

</form>

</body>

</html>

trap.php
<?php
session_start();

$_SESSION['uid']=$_POST['uid'];
$_SESSION['pwd']=$_POST['pwd'];
	if($_SESSION['uid']=='php' and $_SESSION['pwd']=='1234')
	{
?>
<form method="post" action="display.php">
Fruit choice for eat :<select name="fruit">
<option>Select</option>
<option>Mango</option>
<option>Banana</option>
<option>Orange</option>
</select>
<input type="submit" name="submit" value="Select"/>
</form>

<?php
}
else
{
	include('login.php');
	echo "User or Password may be wrong!";
}


?>

display.php
<?php
session_start();
$fruit=$_POST['fruit'];
echo $_SESSION['uid']." you have selected $fruit";

?>

Download session variable example here