PHP如何使用cookie在同一浏览器中管理多个会话？

I'm new to PHP, I read other articles without finding the answer I'm looking for, but still don't know if what I want to do makes sense or not.

I'm using PHP 7.

My user authentication page, checks credentials and then executes session_start(), creating the session server-side and a cookie client-side in the browser.

Each other page of the web application then calls session_start() to resume session information, in this case checking the cookie. Everything works fine so far... at least when I have a single login.

I'd like to be able to have more than one user SIMULTANEOUSLY logged in the same browser (on another tab for example.) using cookie. I don't want to append the session ID to the URL.

I managed to create different session on the server-side using session_id() before session_start() in the authentication page based on username, but the problem is on the client side.

The first successful login (session_start()) creates a cookie and the second login updates the same cookie corrupting the previously created session.

Therefore when it comes to resume the session, session_start() will resume only the last session, mixing the data fetched from DB based on session info.

Is there a way to make session_start() create a cookie for each login and make PHP resume the correct session using cookies?

Any ideas?

FURTHER DETAILS: I'm updating a legacy app trying to fix some security issue. The need for multiple sessions comes from administrative purposeses where admins access the same site. The reason why it's needed a separation of session is that depending of the session info, the data are fetched from a different database. Therefore, a regular usage would only need one session per user, but the administrator he needs to make multiple logins viewing different data depending on that login.

You can use the same session but change the variable names that you are looking for:

if ( $_SERVER['REQUEST_URI'] == '/admin/' ):
    $session_name = 'session1';
else:
    $session_name = 'session2';
endif;
session_start( $session_name );

The default PHP behaviour is to handle sessions using cookies.

..and the default behaviour for browsers is to "reuse" the same set of cookies if you revisit an URL in another tab.. So, like mentioned below:

• The simple way probably is to start another browser. Not the same browser but like firefox and chrome, if you have multiple browsers installed.
• Another way would be to install a browser plugin, like Sessionbox for Chrome or Multifox for Firefox.

Edit, for clarity: I can think of two cases when multiple sessions would be used:

• During development. Depends on the application, but an obvious case would be testing communication between two users.
• After deployment. Though I've never seen a site that required multiple logins for the same user account.

This is my frame of reference. Based on this I assumed the question was for development. I'm not suggesting that the site should require installing extra packages. Flash would be about the only one that's ever gotten away with that..