I believe the following problem is a result of using sessions and fpassthru together.
I have a subscription based site which protects large video files (WMV format between 100-120MB) by storing them beneath web root. Downloading a video file requires the user to click a HTML link which requests a PHP script e.g. download-video.php?video_id=123. If the user is valid (session vars created from sucessful login) the script then creates the necessary headers to trigger a 'Save As' download box, opens the file from beneath web root and sends it using fpassthru.
The problem is as follows:
The user should be able to click other links on the site whilst a file is downloading. But when they do so, the requested page won't load until the download is complete.
As this download script is a seperate PHP request, the user should be able to load other pages on the site whilst the file is downloading.
At time of writing, I've tried almost everything to remove this bug. There must be a problem with using a PHP script rather than a direct web server link to download files.
