Re: squid adding gzip support

Hi,

Thanks Henrik and Robert for all of your suggestions (particularly hints
of where to patch squid-2.5, and about rfc2616, 215 warning).

New issues about this:

1) When to compress:
   a) Client must have sent Accept-Encoding: and gzip has to be listed
      in supported encodings ('compress' could be implemented with not
      too much effort).
   b) Server response should not be Transfer-Encoding: chunked. If it
      is, it should be de-chunked, right?
   c) Content-type of answer is text/html or text/plain (this could be
      moved to gzip_access, I think).
   d) Answer from server is not already compressed :-).
   d) Server response does not contain Content-Range header (in case of
      a miss). I simply won't compress partial data. This is due to
      the fact that Ranges header usually is used on 'resume download'
      operation, and I want to speed up interactive navigation.
   e) gzip_access (new directive) is ok
      I will add this in order to enable compression only on dial-up
      clients (slow clients).
Is this ok?

2) Where to compress:
   I will compress on comm_write.
   Thank you very much for your wise adivce.
   I have to check where to start compressing, since comm_write only
   gets data to be written (other wise, headers will be compressed to).
   Would it be OK to add something like this to struct _fde? (I mean,
   is it the right place?).
    struct {
        unsigned int compress_level:4; /* compression level: 1-9 */
        unsigned int compress_offset;
        /* how many bytes have to skip before to compress */
        z_stream* zstream; /* zlib internal state */
    } compress;

3) Which squid to patch:
   Unless squid 3 is going to be STABLE next week, I have to work on
   squid 2.5, since I have a deadline of 1 month to accomplish this :-(
   Of course, Once this is working, I will start working on a patch
   for squid3.

4) Answer modification:
   a) Should I alter Vary header (by adding Accept-Encoding)?
   b) ETag: May I build it from md5sum of compressed content?

Thank you very much in advance,

-- 
Gonzalo Arana <garana@uolsinectis.com.ar>
UOL-Sinectis S.A.