Which method is used to store cookie data into session file

Question

I am using a small PHP framework.

When calling session_start(), a class implementing SessionHandlerInterface allows a creation of the cookie file throught its method read($id).

A file like sess_533stse23wsdd23rs is created on disk. Good.

Eventually a further call to the SessionHandlerInterface implementation writes more information in the cookie server file. This information can be viewed on call to write($id, $data).

When debugging, I break in the write method implementation and view the call stack and see a call from session_write_close(). I cannot discover where the data passed as parameter to the write is coming from. I do not seem to have this info from the debugger. This type of information is not accessible:

session_write_close(){

// Where this $data is coming from ?

handler...write( $id, $data )

}

In PHP, is there a method to save information to the cookie, so that a call to the session_write_close() will flush this information to the persistent file on disk ?

Answer 1

Ok, finally, from what I discovered, it seems that any data in $_SESSION will be flushed to the cookie file.

Can I get somebody's confirmation ?