Forced downloading large file with php

Question

Many users of my site have reported problems downloading a large file (80 MB). I am using a forced download using headers. I can provide additional php settings if necessary

Answer 1

The problem with PHP-initiated http transfers is that they seldomly support partial requests:

GET /yourfile HTTP/1.1
Range: bytes=31489531-79837582

Whenever a browser encounters a transmission problem, it will try to resume the download. Your php script does not accomodate for that (it's not trivial, so nobody does).

So really avoid that. Redirect users to a static file and let your webserver handle it. If you need to handle authorization, use tricks like symlinks or rewriterules that check for session cookies or even a static permission file (./allowed/178.224.2.55-file-1). Any required extra HTTP headers can be injected likewise, or with a .meta file.