PHP Session ID Variable Returned With AJAX

Question

I'm working on an AJAX login system and am not sure how to return the PHP session variable from AJAX unto the login page. My question is, how do I return the php variable unto the login page, if that is even possible. Below is the sample I created.

Login Page

<?php

session_start();

?>

<form>

    <input type="text" id="username" />

    <input type="text" id="password"/>

    <input type="button" id="submit" />

</form>

<script type="text/javascript" >

    $('#submit').click(function() {

var username = $('#username').val();

var password = $('#password').val();

    $.post('ajax_file.php', 
    {
    username: username,
    password:password,
    }, 
    function (data) {

    /* what do I do here that will return the php variable 
    $_SESSION['user_id'] and let the user be logged in when
    they go to homepage.php*/
    setTimeout('window.location.href="homepage.php"', 2000);
    });});

</script>

Here is the ajax page. I understand that the logic doesn't make sense for the session variable to pop out of nowhere, let's just assume that is was created earlier in the page.

$username = $_POST['username'];

$password = $_POST['password'];

if(login($username, $password)) {

    return $session_user_id = $_SESSION['user_id']; 

}

Have you tried using session_start() at the start of your ajax file? — asprin
– asprin, Commented Sep 4, 2012 at 6:20
@asprin That suggestion gave me the right answer. Endy gave it to me earlier though but thanks for the simplified answer. — thank_you
– thank_you, Commented Sep 4, 2012 at 6:52

Endy · Accepted Answer · 2012-09-04 05:50:34Z

2

You can just do the AJAX post, set the session variable to the session in the page receiving the post, and it will be stored in the session (it's the same session). In the AJAX callback forward the user to the home page.

Of course you must consider the scenario that the login credentials are incorrect.

answered Sep 4, 2012 at 5:50

Endy

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3 Comments

thank_you Over a year ago

If I'm reading this right, my code is correct. Because session_start() is in the file the returned ajax file will have $session_user_id stored. Or do I have to write session_start() within the ajax_file.php as well? Thus, a further explanation would be great.

Dmitry Makovetskiyd Over a year ago

if you start the session from the file you are requesting , it wont work,.. but i think you can do it , by retrieving a response with a cookie.. I am not sure how to it with ajax, but i know how to to it with curl, for example.. it is a bit convoluted..see my answer

Endy Over a year ago

I don't do PHP so I can't go into details with it, but as far as I know once you create a session the server will handle session tracking for you and you should not need to explicitly create a new session on each page request.

Community · Accepted Answer · 2023-11-17 20:18:02Z

The trick is that your JavaScript doesn't even have to know about sessions at all; you can configure PHP to use HttpOnly cookies for its session management via the respective ini setting.

I would implement the AJAX script like this:

session_start(); // start the session

if (login($username, $password)) {
    // alter session to hold user id
    $_SESSION'user_id'] = $user_id_from_database_or_something;
    return true;
} else {
    return false;
}

The AJAX complete handler looks at the return value and redirect to the homepage if it was true. Something like below (I'm assuming that the PHP return is translated into something like echo json_encode($return_value):

if (data) {
    // do redirect
} else {
    // login failed
}

Then, when the user comes to the homepage their browser would send a session cookie so you can determine if they're logged in.

Shail · Accepted Answer · 2012-09-04 06:12:46Z

0

Improving the Answer

FOr Jquery, USe function below

function sendAjax(showAllExist, controller) 
{

   $.ajax({
   type: "post",
   url: login.php,
   data: yourformdatacomeshere,
   beforeSend:  function() {
         //do whatever you want to do before request
    },

    error: function() {
        //display in case of error
    },

    success:  function(data) {       
       //display in case of error
    if(data!=""){
        //redirect use to home pahe
        window.location.href ='homepage.php';
    }else{
        //display login is not correct
    }

    },

    complete:  function() {
        //hide any event which you have started on beforeSend 
    }

 });     
    return true;    
}

edited Sep 4, 2012 at 6:12

answered Sep 4, 2012 at 5:59

Shail

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2 Comments

thank_you Over a year ago

I don't think this really answers my question. Plus, I'm writing my AJAX in jQuery.

Shail Over a year ago

Use session_start in Ajax file also

Dmitry Makovetskiyd · Accepted Answer · 2012-09-04 06:15:06Z

0

Cant you just do this:

     $.post('ajax_file.php', 
    {
    username: username,
    password:password,
    loginSession: <?php echo  $_SESSION['user_id']; ?>
    }, 
    function (data) {
    //Check here if login is correct.
    if correct, create this variable:
   var logged= "?logged="+data.SessionID;
    /* what do I do here that will return the php variable 
    $_SESSION['user_id'] and let the user be logged in when
    they go to homepage.php*/
    setTimeout('window.location.href="homepage.php"+logged+"'", 2000);
    });})

When data comes back go the homepage.php with a sessionID.

on the php script do this:

if(isset($_GET['logged'])){
  start_session();
  $_Session['LOGGED']='true';
}

answered Sep 4, 2012 at 6:15

Dmitry Makovetskiyd

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Comments

Rajat Modi · Accepted Answer · 2012-09-04 07:12:01Z

use this method which is improvised above shail answer.

your ajax file code

$username = $_POST['username'];

$password = $_POST['password'];

if(login($username, $password)) {
  $session_user_id = $_SESSION['user_id'];// this is from your code
  $responseArray = array("message"=>"success","sessionId"=>$session_user_id);
}
else
{
  $session_user_id = "";
  $responseArray = array("message"=>"error","sessionId"=>$session_user_id);
}
echo json_encode ( $responseArray );
die ();

then in ajax function make below changes.

 var frmdata = jQuery("#logindata").serialize(); // which contains the data of username and password
 jQuery.ajax({
     type : "POST"
    ,url :'ajax_file.php'
    ,data :frmdata
    ,dataType: "json"
    ,success : function(data){               

        if(data.message == "success")
            {
                //redirect it to your desire page
            }
            else
            {
                //redirect it to your login page
            }

       }
 ,beforeSend: function(html){
        // some loader goes here while ajax is processing.
       }
});

hope this help feel free to ask anything for this answer.

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