What point does PHP return file size upload error?

TheFinnisher

I was wondering if someone could tell me when the server/PHP returns file size error?

Is it after the file has been uploaded to the temp directory or before? Will the file actually have to reside in the temp folder for PHP to know it's too large?

How PHP deal with the MAX_FILE_SIZE input form field and at which point does it realize the file is too large? I've read some browsers can also use this field to prevent too large file uploads before sending it to the server.

Would appreciate any insight!

suntra

I suggest you to read this page first...

http://ca.php.net/manual/en/features.file-upload.php

TheFinnisher

Thanks Suntra for your link,

I had read that page a few times but it's still a little unclear to me...

The section on that page is what I'm trying to figure out:

The PHP script which receives the uploaded file should implement whatever logic is necessary for determining what should be done with the uploaded file. You can, for example, use the $_FILES['userfile']['size'] variable to throw away any files that are either too small or too big

I guess I'm wondering if the file is uploaded completely to the server FIRST and then I can use logic to "throw" away the file?

Say for example I am trying to upload a file that is 20MB large but my server settings allow a max of 2MB and I have also set the MAX_FILE_SIZE to 2MB. Will the 20MB file has to travel to the server in it's entirety before PHP or I can throw it out?

Thanks,

Thomas

suntra

That is an information I do not know!

I would tend to say the Apache waits for the sent query (from your browser) to be complete before send it to PHP, but I'm not sure about that one... so if what I say is true, the wholefile will be uploaded, then Apache "communicates" with PHP which will reject the file since it's too big...

Weedpacket, where are you when we need you ?! 😛

TheFinnisher

Suntra,

I did some tests and it appears as if you are right. I made a test form and uploaded various files with various file sizes. It seemed as if the files had to be uploaded to the temp folder in their entirety in order to "throw" them out.

It seems kind of silly to have to wait for a 4MB file to upload completely until you can tell the user with PHP that the file was too big and that allowed size is 2MB. Or whatever you want to tell using the $_FILES global variables.

Another thing I realized in my test was that I also had to wait for the upload until I could figure out the MIME type of the file (with $_FILES['userfile']['type'])...So I realized that it would probably be smart to pre-check the file extension type before proceeding to upload (and then further check MIME).

I think I will have to learn more about MIME types too. If anyone knows of a good tutorial I would be grateful!