Nathan Long Nathan Long - 6 days ago 6
PHP Question

How to gracefully handle files that exceed PHP's `post_max_size`?

I'm working on a PHP form that attaches a file to an email, and trying to gracefully handle cases where the uploaded file is too large.

I've learned that there are two settings in

php.ini
that affect the maxiumum size of a file upload:
upload_max_filesize
and
post_max_size
.

If a file's size exceeds
upload_max-filesize
, PHP returns the file's size as 0. That's fine; I can check for that.

But if it exceeds
post_max_size
, my script fails silently and goes back to the blank form.

Is there any way to catch this error?

Answer

From http://ca2.php.net/manual/en/ini.core.php#ini.post-max-size

If the size of post data is greater than post_max_size, the $_POST and $_FILES superglobals are empty. This can be tracked in various ways, e.g. by passing the $_GET variable to the script processing the data, i.e. , and then checking if $_GET['processed'] is set.

So unfortunately, it doesn't look like PHP sends an error. And since it sends am empty $_POST array, that is why your script is going back to the blank form - it doesn't think it is a POST. (Quite a poor design decision IMHO)

This commenter also has an interesting idea.

It seems that a more elegant way is comparison between post_max_size and $_SERVER['CONTENT_LENGTH']. Please note that the latter includes not only size of uploaded file plus post data but also multipart sequences.

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