Re: Git-aware HTTP transport

From: "Shawn O. Pearce" <spearce@spearce.org>
To: david@lang.hm
Cc: Junio C Hamano <gitster@pobox.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	git@vger.kernel.org
Subject: Re: Git-aware HTTP transport
Date: Thu, 28 Aug 2008 10:43:34 -0700	[thread overview]
Message-ID: <20080828174334.GF21072@spearce.org> (raw)
In-Reply-To: <alpine.DEB.1.10.0808281033070.2713@asgard.lang.hm>

david@lang.hm wrote:
> On Thu, 28 Aug 2008, Shawn O. Pearce wrote:
>> david@lang.hm wrote:
>>> On Thu, 28 Aug 2008, Shawn O. Pearce wrote:
>>>>> "Shawn O. Pearce" <spearce@spearce.org> writes:
>>>>
>>>> Yes, I really did mean for this part of the protocol to be in binary.
>>>
>>> except that HTTP cannot transport binary data, if you feed it binary data
>>> it then encodes it into 7-bit safe forms for transport.
>>
>> So then how does it transport a GIF file to my browser?  uuencoded?
...
> I could be wrong, but I'm pretty sure I'm not. to test this yourself find 
> a webserver with an image file and retrieve it via telnet (telnet 
> hostname 80<enter>GET /path/to/file HTTP/1.0<enter><enter>) and what will 
> come back will be text.

  $ telnet www.google.com 80
  Trying 74.125.19.104...
  Connected to www.google.com (74.125.19.104).
  Escape character is '^]'.
  GET /intl/en_ALL/images/logo.gif HTTP/1.0

  HTTP/1.0 200 OK
  Content-Type: image/gif
  Last-Modified: Wed, 07 Jun 2006 19:38:24 GMT
  Expires: Sun, 17 Jan 2038 19:14:07 GMT
  Cache-Control: public
  Date: Thu, 28 Aug 2008 17:40:44 GMT
  Server: gws
  Content-Length: 8558
  X-Google-Backends: /bns/pq/borg/pq/bns/gws-prod/staticweb.staticfrontend.gws/16:9836,dauf30:80
  X-Google-Service: static
  X-Google-GFE-Request-Trace: dauf30:80,/bns/pq/borg/pq/bns/gws-prod/staticweb.staticfrontend.gws/16:9836,dauf30:80
  Connection: Close

  GIF89a	\x01n���������������έ	���\x18E�\x18I�\x104�\x10<��\x18�������\x10ƾ����\x18M������������ｾ�����$c!Y�����\x18QΜ�������e֮c��1e�J}<�������s�����9q�k

Very funny.  It trashed my tty.  Even reset won't restore the
settings.  Anyway.

I chose the Google logo on the Google homepage because I know we
try really hard to conform to standards, so we can have the biggest
possible user base.  Micro$oft or Yahoo! probably would have come
out the same way.  Or some image on kernel.org.

Anyway, I didn't send any browser data, so the server had to assume
the dumbest f'ing browser on the planet, and I got back binary data.

-- 
Shawn.