Question

We have files that are hosted on RapidShare which we would like to serve through our own website. Basically, when a user requests http://site.com/download.php?file=whatever.txt, the script should stream the file from RapidShare to the user.

The only thing I’m having trouble getting my head around is how to properly stream it. I’d like to use cURL, but I’m not sure if I can read the download from RapidShare in chunks and then echo them to the user. The best way I’ve thought of so far is to use a combination of fopen, fread, echo’ing the chunk of the file to the user, flushing, and repeating that process until the entire file is transferred.

I’m aware of the PHP readfile() function aswell, but would that be the best option? Bear in mind that these files can be several GB’s in size, and although we have servers with 16GB RAM I want to keep the memory usage as low as possible.

Thank you for any advice.

Answer 1

HTTP has a Header called “Range” which basically allows you to fetch any chunk of a file (knowing that you already know the file size), but since PHP isn’t multi-threaded aware, I don’t see any benefit of using it.

Afaik, if you don’t want to consume all your RAM, the only way to go is a two steps way.

First, stream the remote file using fopen()/fread() (or any php functions which allow you to use stream), split the read in small chunks (2048 bits may be enough), write/append the result to a tempfile(), then “echoing” back to your user by reading the temporary file.

That way, even a file 2To would, basically, consumes 2048 bits since only the chunk and the handle of the file is in memory.

You may also write some kind of proxy manager to cache and keep already downloaded files to avoid the remote reading process if a file is heavily downloaded (and keep it locally for a given time).