Who is they in "they told me that via socket I could do it"? Did they also tell you that you couldn't use any of the many programs already written for this purpose like scp or ftp?

Inventing your own file-transfer protocol seems like a fun way to waste a lot of time though. I'd do it by writing out a little MIMEy header for each file. Something like:

    Filename: foo.zip
    Size: 100010
[download]

Then send the file, no encoding needed since the server knows how much data to expect. A new header could be sent after the file to send another file, or some kind of "All Done" message. The code for client and server should be easy to write.

Of course this lacks all kinds of nice stuff that scp or ftp will do for you! Key stuff to worry about - security, wacky characters in filenames, losing the network connection in the middle of a transfer, etc.

-sam