I had to solve this exact problem about 6 months ago for an application that parsed uploaded files real time and fed back progress indicators to the user. There is a great description of how to do a search in progress out there by merlyn, but this situation is a bit different in that the main application window is handling the upload, and cannot be refreshed.

I did this in a mod_perl2 handler using Apache::Request, but you should be able to accomplish the same with cgi scripts. Upon the user clicking 'Upload', I used javascript to open a small status window which refreshed waiting for the presense of upload status data. Meanwhile the main window begins the upload process. An UPLOAD_HOOK (see a::r docs) subroutine measured the amount of bytes received from the client and wrote it to a status file which the monitor read.

Now, this worked very well for displaying the amount of bytes received from the user. As for determining the percentage of file uploaded, a::r provides the following useful method:

my $size = $upload->size;

However I did not find the size returned to be reliable when referenced from within the UPLOAD_HOOK subroutine. I suspect is determined once the file is fully uploaded. So I wasn't able to give the user a realistic estimation of when the file would be done uploading.

But I was able to parse the contents real-time, display the results to the user, and terminate the upload if the errors in the file exceeded a certain threshold, which got good feedback from the users. I got some flak from reviewers of the technique, but it worked very well. I was able to pass back to the user accurate information about where in the file errors were, which saved them a great deal of time.

HTH

In reply to Re: Upload Progress Bar by redhotpenguin
in thread Upload Progress Bar by Anonymous Monk

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