PHP $_SESSION can it hold large files?

Question

I'm building a multi-page form with PHP. I'm storing most of the value's in $_SESSION. Using the following method...

$_SESSION['title'] = $_POST['title'];

It's working fine so far but I'm not sure if it will be able to hold PDFs, videos, ect.

Does the $_SESSION only hold strings & intigers, or can files be stored there?

possible duplicate of [PHP - Store Images in SESSION data?](http://stackoverflow.com/questions/754145/php-store-images-in-session-data) — Michael Berkowski, Oct 05 '11 at 20:39
the session values are stored in a file, so I don't think it can store and end of file byte — Máthé Endre-Botond, Oct 05 '11 at 20:40

score 7 · Accepted Answer · answered Oct 05 '11 at 20:42

7

The maximum size of a $_SESSION is the maximum memory allowed to a PHP script, but chances are if you even get to 1/3 of that, you're doing something wrong.

$_SESSION, as a rule, should only be used to keep what information is needed by the user for the majority of the site page views. It is highly improbable, that you will actually need a file on each page.

Here's a better option, store a temp file on the disk and assign the path to the temp file in the $_SESSION. Then, when you need it, read the file to the user.

answered Oct 05 '11 at 20:42

cwallenpoole

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I'm reading that the tmpfile() is automatically removed at the end of the php script? Wouldn't that make it not possible for use with a 'multi-page' form? – Philip Kirkbride Oct 05 '11 at 20:50
Create a file named by the `PHPSESSID` and have a cron job clean them up after a given interval. – cwallenpoole Oct 05 '11 at 20:59

score 5 · Answer 2 · answered Oct 05 '11 at 20:41

I do not suggest you to store big value because this information is stored in your server. You should serialize a PHP object that will contain path to those file if you want to keep some reference to these files.

Edit: The session is loaded into memory at run time, so in theory it's limited by the memory_limit in php.ini.

score 2 · Answer 3 · answered Oct 05 '11 at 20:40

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I'm not sure whether you would be able to store an entire file into $_SESSION, but you could upload your file to the server and store only a path to the file.

answered Oct 05 '11 at 20:40

JanLikar

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score 1 · Answer 4 · answered Oct 05 '11 at 20:41

By default the sessions are stored as files on the server. The only limit opposed is the PHP script memory limit - eg 64MB, which can be controlled. Files can be stored in both binary and text format but I would question the need to do so - after all, why would you do that?

score 0 · Answer 5 · answered Oct 05 '11 at 20:41

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$_SESSION is stored on server in the folder where it defined in the php.ini

so as long as your server has space you can store anything on the $_SESSION

answered Oct 05 '11 at 20:41

Eli Y

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PHP $_SESSION can it hold large files?

5 Answers5