Session Management in PHP

 Managing Sessions and Using Session Variables

 

 

 

What is  session?

• Session is the time spent by a single user on a website.
•  Session can't be shared by any other users. Ex: Login to website.
•  When a session is created, One unique-id is provided for each user at the time of session
  start. Ex: sess_07ne2iojd9983gl3ic2a2e06q0
•  Session can create user specific variables.
•  These variables are stored at server side. Whereas cookies are stored at client side.
•  Session-ids available in WAMP/XMPP’s tmp directory.
• Data available in session accessed by all the pages in a web application.
  

 

Creating a Session and Retrieving Session ID

session_start() :  Creates a new session and generates a session ID.
session_id()     :  Displays session ID.

session_create.php

<?php

 
session_start();
echo session_id();

?>

output:

sess_07ne2iojd9983gl3ic2a2e06q0 

Creating Session Variables and Reading Session Variables:

 

$_SESSION['user']="John";
echo "<br>Welcome..Mr ". $_SESSION['user'];

add above 2 lines in session_create.php and run it. 

 

Example

<?php
 

session_start();
echo session_id();

$_SESSION['user']="John";
echo "<br>Welcome..Mr ". $_SESSION['user'];

?>

** session variable, once it is created, can be accessed from any page in 

the web application.

** In every page, first line should be session_start() so that, session is 

continued to the next page. And session variables can be accessed by that page.

** Session Variables available within session. Once the Session destroyed 

all the variables get cleared from the session.

Clearing session variables and destroying a Session:

session_unset() : clears all session variables

session_variable_unset.php

<?php

 
session_start();

unset($_SESSION['user']);

echo "<br>Hello ". $_SESSION['user']; 

?>

Output

Gives Unified variable error

 

Counting page views using session variable

 

  

Example:

session_views.php

<?php
 

session_start();
 

if(isset($_SESSION['viewscount']))
 

$_SESSION['viewscount']=$_SESSION['viewscount']+1;
 

else
 

$_SESSION['viewscount']=1;
 

echo "<br><h2>This website Viewed=". $_SESSION['viewscount']."times";
 

?> 

 Retrieving session data from another page in a website.

session_page1.php  

<?php
 

session_start();
 

$user['username'] = "John Doe";
$user['mobile'] = "4334523455";
$user['gender'] = "Male";
$user['email'] = "john123@example.com";
 

$_SESSION['user'] = $user;
 

print "<a href=\"session_page2.php\" > Move to Page2 </a>";
 

?> 

session_page2.php

<?php
 

session_start();
 

echo $_SESSION['user']['username']."<br>";
echo $_SESSION['user']['mobile']."<br>";
echo $_SESSION['user']['gender']."<br>";
echo $_SESSION['user']['email']."<br>";
 

?> 

Ref: http://php.net/manual/en/function.session-start.php
To find more on  sessions.

session_info.php

 
<?php
 

session_start();
 

echo "<b>Few Important Session functions are as follows:</b><br/>";
 

echo "<b>Session ID is:</b>".session_id()."<br/>";
 

echo "<b>Session module name is:</b>".session_module_name()."<br/>";
 

echo "<b>Session path is:</b>".session_save_path()."<br/>";
 

echo "<b>Session name is:</b>".session_name()."<br/>";
 

?>

What you learned in this tutorial blog.

How to pass form variables from one page to other page in PHP ?

How to Send Submissions to Your MySQL Database Using PHP
How to pass form variables from one page to other page in PHP ?
How to Create, Access and Destroy Sessions in PHP
how can you share data between PHP pages?