As part of my attempt to create an ASP.net that has the same look and feel as an existing php application from another developer. (more about it can you read here: [How to share sessions between PHP and ASP.net application?](https://stackoverflow.com/questions/2544389/how-to-share-sessions-between-php-and-asp-net-application))
I'm in the middle of the process of sharing userlogin state between my ASP.net and PHP application.

I have links like signin.aspx?foo=asdhhjkasd (ASP.net) and signin.php?foo=asdhhjkasd which tell the other application which user credentials should be used for authenticating a user.

Right now I'm stuck with PHPs session management: The existing php application consists of a index.php which includes several (some out of 100) other php files and performs its function. There is a sessionmanagement (session\_start() involved et cetera.

What I want to do, is to call a page call signin.php with some parameters. Based on whether the used logged into the php application before or not, I simply want to redirect to the index.php, but I can't get a hold of the session variables.

How must my signin.php look like, to access the session variables used in the index.php. This is what I tried so far:

```
<?php
    // session_start(); tried it with or without it
    if($_SESSION['user_id'] != "")
    {
        header('Location:index.php');
    }
    else
    {
          echo "no redirect";
    }
?>

```

I always get "no redirect" printed.

Or is my thinking wrong and it is not possible to access the session variables from another page in php when there is no post/get action involved?

Maybe I should say that my PHP abilities are a bit limited.