Session Newbie. Help!

Paul_help_

Hi guys.

This is just a quick one.

I am in the process of learning about sessions.

In the book I am reading, it is explaining how to create a user login system.

I understand most of it, so I only have one question to be honest.

In the book I am reading, it goes on to explain how the code works and it states:

The script starts by creating a new session (or picking up an existing one) with session_start() .

The thing is, I don't know much about how php picks up an exisitng session.

I need to ask:

1) For a file to pick up an existing session, does that existing session need to have been created in the same file?
Or can it be the opposite?,,, for example, lets say we have 2 pages (part of the same site):

firstpage.php

and

secondpage.php

Lets say "firstpage.php" creates a session to begin with.

If "secondpage.php" creates a session, is "secondpage.php" going to pick up this exisitng session created by "firstpage.php"?

Or is "secondpage.php" session going to be a fresh, unique session to that page only?

Paul.

NogDog

The session_start() both looks for a HTTP cookie from the browser as well as sending one to the browser. That cookie contains a unique value that identifies the session. PHP therefore stores the session data on the web server, while the browser is responsible for exchanging that session cookie (as long as it is valid) so that the PHP code knows which session data to use. Therefore, when any PHP script on your sited does session_start(), if it received a valid session cookie, then it uses that ID to grab that user's session data and populate it in $SESSION. If no such cookie is received from the browser (or it's expired or such), then it will create a new session ID, send that in a cookie to the browser, and create an empty $SESSION array.

Weedpacket

For full details, see the Session Reference, including the Introduction and Basic usage example.

Paul_help_

Hi.

Thanks for the replies.

I am already aware of most of what you have just said (as i have read up on a fair amount).

The only thing I cannot find an answer to is my one question (above).

If you could answer it, it would be extremely helpful.

Paul.

schwim

Hi there Paul,

The session persists across pages. If the session start finds a valid unique identifier stored in your browser, it renews that session instead of starting a new one.

Paul_help_

Thanks bro.

Weedpacket

Right, as NogDog said:

NogDog wrote:
Therefore, when any PHP script on your sited does session_start(), if it received a valid session cookie, then it uses that ID to grab that user's session data and populate it in $SESSION. If no such cookie is received from the browser (or it's expired or such), then it will create a new session ID, send that in a cookie to the browser, and create an empty $SESSION array.

Or the first paragraph of the basic example page in the manual:

Session IDs are normally sent to the browser via session cookies and the ID is used to retrieve existing session data. The absence of an ID or session cookie lets PHP know to create a new session, and generate a new session ID.

paknoukri

Hello when ever you use a session in the page a.php and go to the next page b.php the same session ID will be used across all your website pages till you destroy the current session. The session destroys when you click on logout button in your suppose admin panel and you have put session destroy php code in the logout.php file. thanks.