Creating a file progress bar in PHP

Question

Does anyone know of any methods to create a file upload progress bar in PHP? I have often heard that it's impossible.

I have one idea, but not sure if it would work: have a normal file upload, but instead submit to an iframe. When this is submitted, store the file information (size and temp location) in the session. At the same time, start an AJAX call to every say 10 seconds to check the size of the file compared to the size stored in the session. This would return the size to the AJAX and then a progress bar would be sized and maybe display the uploaded size to the user.

Thoughts?

Answer 1

"Old school", but a PHP + Perl technique: http://www.raditha.com/php/progress.php

Answer 2

You're pretty much figured out how to do it. The main problem is you usually don't have access to the size of the uploaded file until it's done uploading.

There are workarounds for this: Enabling APC, you to access this information if you include a field called "APC_UPLOAD_PROGRESS" and use apc_fetch() for retrieving a cache entry with the status.

There's also a plugin called uploadprogress but it's not very well documented and doesn't work on Windows (last I checked anyway).

An alternative is to use Flash for doing it. See scripts like FancyUpload.

Before APC came along I had to write a CGI script in C that wrote information to a text file. APC seems like a much better way to do it now though.

Hope this helps.

Answer 3

From PHP 5.4 it is in session extension: http://php.net//manual/pl/session.upload-progress.php

Answer 4

I'd recommend looking at SWFUpload to accomplish what you want. It's fairly flexible and supports queueing of files, so you could even handle multi-file uploads.

Answer 5

In pure PHP, you are correct: it's not possible.

If you AJAX-ify this, then you could do what you're describing. The only progress meters I've ever seen are in Javascript or Flash, though I imagine Silverlight could do it also.

Answer 6

In my opinion, the best / easiest solution is to build a small flash widget, that consists of an 'Upload' button and a progress bar. Flash gives you very detailed feedback on how much data has been uploaded so far, and you can build a nice progress bar based on that. Doesn't require inefficient polling of the server, and in fact doesn't require any changes at all to your server code. Google for 'flash uploader' and you'll find many people have already written these widgets and are happy to sell them to you for a buck.