Question

I want to use two independent $_SESSIONs in a single PHP script.

I have attempted to verify that this is possible using the following code.

error_reporting(-1);


session_name('session_one');
session_start();
$_SESSION = array();
$_SESSION['session_one_var'] = 'test_one';
$output1 =
(
   "session_id(): '" . session_id() . "'.<br/>\n" .
   "session_name(): '" . session_name() . "'.<br/>\n" .
   print_r($_SESSION, true)
);
session_write_close();
$_SESSION = array();


session_name('session_two');
session_start();
$_SESSION['session_two_var'] = 'test_two';
$output2 =
(
   "session_id(): '" . session_id() . "'.<br/>\n" .
   "session_name(): '" . session_name() . "'.<br/>\n" .
   print_r($_SESSION, true)
);
session_write_close();
$_SESSION = array();


echo "$output1<br/>\n<br/>\n$output2";

Output:

session_id(): 'f19aecd8d3ce0c5d444456d2387c6e35'.
session_name(): 'session_one'.
Array ( [session_one_var] => test_one )

session_id(): 'f19aecd8d3ce0c5d444456d2387c6e35'.
session_name(): 'session_two'.
Array ( [session_one_var] => test_one [session_two_var] => test_two ) 

I expect the output to show that the session named ‘session_one’ contains array(‘session_one_var’ => ‘test_one’) and the session named ‘session_two’ contains array(‘session_two_var’ => ‘test_two’). Instead, ‘session_two’ seems to be the same session as ‘session_one’.

If I insert a line ‘session_regenerate_id();’ after the second ‘session_start();’ line, a different session id is reported for ‘session_two’, but the output is otherwise the same. See below.

session_id(): 'f19aecd8d3ce0c5d444456d2387c6e35'.
session_name(): 'session_one'.
Array ( [session_one_var] => test_one )

session_id(): '3bcc74a7bcbac30e680c5b94fadcede1'.
session_name(): 'session_two'.
Array ( [session_one_var] => test_one [session_two_var] => test_two ) 

What am I doing wrong?

I know similar questions have been asked on this forum before, here and here, but the answers offered so far have failed to enlighten me.

Any help will be much appreciated.

Answer 1

The session ID is read from a cookie when you run the first session_start() and sticks around even if you use session_write_close() (otherwise you wouldn’t be able to call session_start() to reopen the same session)

I don’t have PHP handy here to test this, but in theory, you can do session_id($_COOKIE['session_two']); before the second session_start() to switch to the correct ID.

I may have the cookie name wrong, though, so you may want to printr($_COOKIE); to see which cookies are set.

Edit: I forgot to mention: The session’s cookie name is based on session_name, or at least it is if you only use a single session in a file.