PHP: whats the total length of a post global varia

Question

I was wondering if anybody knows the total length that a post global could be. e.g:

$_POST['formInput'] = "hello world, how long can i be?";

I am creating a site where someone will enter an unknown amount of chars into a textarea, so potentially it could be 2 pages on a word document. So if anybody knows of any other methods of how i can do this apart from using a post global? (it cant be saved in a file, as its important data that i dont want other people to find) That would be very helpful.

Thanks

Answer 1

$_POST is populated from the body of a HTTP-request. Since there are no restrictions on the size of a HTTP-request, there are no restrictions in the protocol layer. However PHP has some limitations on how much input it will read. You can control this with the ini-setting post_max_size

Answer 2

Check your php.ini for post_max_size. This is typically about 8mb by default, but if you're on shared-hosting, it could definitely vary.

; Maximum size of POST data that PHP will accept.
post_max_size = 8M

You'll have to use $_POST if you wish to send large amounts of data to the server. For further study, I'd suggest checking out POST Method Uploads in the documentation.

Answer 3

If you want some large amount of data sent from the browser to the server, you'll have to use HTTP POST method -- which means the data will be received, on the PHP side, in the $_POST superglobal array ; there's not much you can do about that.

The configuration directive post_max_size defines the maximum amount of data that can be received using the POST method -- you might need to set that to a value higher than the default one, depending on your needs.

And, as said on the documentation of post_max_size, the value set for memory_limit can also have its importance.

Answer 4

Another problem can be the default limit in php.ini for directive max_input_vars (default 1000), not only the post_max_size. If you have e.g. a very large form with thousands of checkboxes the $_POST array will have only 1000 keys.