|
|
|
|
Bookmark this on Delicious
Share on Facebook
 Slashdot It!
Digg  session_write_close
Write session data and end session
(PHP 4 >= 4.0.4, PHP 5)
<?
Code Examples / Notes » session_write_closerisaac
Workaround if session_write_close() still doesn't write sessions fast enough: I found with one PHP login system that even session_write_close() was not setting the session variables before I transferred pages with a Location: header. So the user would log in, I would create the $_SESSION variables, call session_write_close() and then transfer to the secure page using header(Location:...). The secure page would check for the session vars, not find them, and force the user to log in again. After the second login the session would be found and they could continue. My workaround was to create the $_SESSION variables with 0 values before writing the initial login page. Then I updated the session vars with the login results and used the header() function to switch to the secure location. Once the session vars have already been created, updated values are assigned quickly. Problem solved. Just be sure the secure page checks both that the $_SESSION var exists AND that it's not 0. 20-apr-2002 03:48
This function is very useful for session objects. The class def'n of an obj needs to be included before the session is started. You can ignore this by closing the session with this function, and then use session_start() to restart it. Do this after including the class definition, but before using the session variable.
cottoantispam
This function is useful for forcing serialization of session data but it can introduce difficult-to-track bugs if it's called more than once per session_start() call. Since it doesn't have a return value or raise an exception there won't be any indication that the serialization failed and the code will continue normally. Only when a user visits a page that depends on unsaved session data will there be any indication of the failure. As far as I can tell this affects both the default and custom session handling functions. <? session_start(); $_SESSION['foo'] = 'box'; session_write_close(); if (array_key_exists('visited',$_SESSION) { echo "welcome back!\n"; # will never happen } else { echo "I don't know you.\n"; $_SESSION['visited'] = true; session_write_close(); } ?> cenaculo
This function is essencial when you change $_SESSION[] variables and then, at some poit in the middle of the script, you send an header("Location: http://...") function to the browser, because in this case the session variables may not be saved before the browser change to the new page. To prevent from lossing session data, allways use session_write_close before this header function. session_write_close will force session data to be saved before the browser change to the new page. Hope this will help you not to loose 1 day wondering why people could not authenticate or make other changes in session vars in your site. bkatz
session_write_close() worked as a lifesaver for me when automatically uploading files to a user (forcing a download instead of a link). If files are large, and since session_start() does not allow another page using session_start() to proceed until it's done, i was not able to upload more than one file at a time. By using session_write_close() before beginning the file upload, my users can now download as many big files as they like, at the same time. Example: <? session_start(); /* Do session stuff here; security; logging; etc. */ session_write_close(); /* NOW write out the requested file. */ header("Content-type: audio/x-mpeg"); /* or whatever type */ header("Content-Disposition: attachment; filename=" . $filename); header("Content-Length: " . $filesize); header("Content-Transfer-Encoding: binary\n\n"); header("Pragma: no-cache"); header("Expires: 0"); $file_contents = file_get_contents($filepath); print($file_contents); ?> nakanishi
Make sure that you call session_start() again after session_write_close() if you rely on the SID rewriting. Otherwise it will not be rewritten.
jp
It is a good idea to call session_write_close() before proceeding to a redirection using header("Location: URL"); exit(); because it ensures the session is updated (in a file or into a database, depending on the handler you're using) BEFORE you redirect the visitor somewhere else. JP. kumar mcmillan
if you are trying to work with a larger code base meant for a specific application... and it implements some custom session save handlers, it appears there is no way to reset those save handlers back to the default php state if they are getting in your way. my workaround: session_write_close(); // close the session at the top of the page :) 26-apr-2007 11:11
I was having trouble with session data being lost / not carrying over to other pages when using header("Location: ..."), and session_write_close() was not helping. I was writing to $_SESSION by doing: $_SESSION = $myArray; I eventually found that doing it this way helped: foreach($myArray as $k => $v) { $_SESSION[$k] = $v; } The problem was strange; I've assigned arrays to $_SESSION countless times and never had trouble with it. In fact, I was doing it in many places elsewhere in the same application, and I never ran into any problems. I spent hours figuring out what was happening. Hope this saves time for somebody out there. editorial
Further to the comment by nakanishi at mailstyle dot com, it appears that calling session_write_close() followed by session_start() causes issues if you have more than one browser window/tab open in the session, and have a large session data array. I have an intermitent (and hard to replicate reliably) issue with session_start() never being called or not returning - the script hangs before the session headers are written. I'm puting this down to trying to be too clever rather than to a bug per se.
steve
For the session problem when using header("Location:..."), I found session_write_close() not to help me on the my IIS server using PHP in CGI mode. The problem was the PHPSESSID cookie was never being set, so I did it the manual way: header("Set-Cookie: PHPSESSID=" . session_id() . "; path=/"); Worked for me this way! unspammable-iain
As we all know, if an object is serialised, then the class definition must be included _before_ it is unserialised. My framework has an enormous number of class files, and including them all at the beginning of the script was really taking it's toll on my system (memory and execution time) so I switched to including required classes at the top of each class file that used them using require_once. This caused problems because I start my session at the very beginning of my script's execution, but all my class files aren't there at the beginning!! So no in my special 'require' function, I do the following: if(!class_exists($to_require)) { session_write_close(); require_once('path/to/classes/'.$to_require.'.php'); session_start(); } This is a considerably smaller performance hit that including every class that the application uses at the very beginning of the application. tyler
Along the same lines as what cenaculo at netcabo dot pt, bkatz at usefulengineering dot com, and editorial at literati dot ca said about making sure you session_write_close(), don't forget to ob_end_flush() if you're using output buffering. I've been having some weird hanging issues when I tried to navigate away from a page with content streaming in an Iframe or a separate window. Instead of: <? ob_start(); session_start(); /* Do session stuff here; security; logging; etc. */ session_write_close(); /* NOW write out the requested file. */ header("Content-type: audio/x-mpeg"); /* or whatever type */ header("Content-Disposition: attachment; filename=" . $filename); header("Content-Length: " . $filesize); header("Content-Transfer-Encoding: binary\n\n"); header("Pragma: no-cache"); header("Expires: 0"); $file_contents = file_get_contents($filepath); print($file_contents); ?> Do: <? ob_start(); session_start(); /* Do session stuff here; security; logging; etc. */ session_write_close(); /* Make sure data is actually flushed out to the browser */ ob_end_flush(); /* NOW write out the requested file. */ header("Content-type: audio/x-mpeg"); /* or whatever type */ header("Content-Disposition: attachment; filename=" . $filename); header("Content-Length: " . $filesize); header("Content-Transfer-Encoding: binary\n\n"); header("Pragma: no-cache"); header("Expires: 0"); $file_contents = file_get_contents($filepath); print($file_contents); ?> |
Change Language
session_cache_expire session_cache_limiter session_commit session_decode session_destroy session_encode session_get_cookie_params session_id session_is_registered session_module_name session_name session_regenerate_id session_register session_save_path session_set_cookie_params session_set_save_handler session_start session_unregister session_unset session_write_close |
