Gmail Technical Rant

[Graycode]

Your experiment is very interesting.

With the local.ptron being a completely different host name, it's obvious they should not have been mixed up to result in the plain-text garbage. On the surface that appears to be a Proxo bug. Firefox is probably be re-using its connection to the proxy after the 204, but Proxo does not realize the 204 was all done and that the browser's new communication is a completely different request.

Can a Proxo header filter safely provide "Connection: Close" back to the browser for every 204 response that doesn't also have a "Content-Length: 0" header? That should keep the browser from trying to re-use its connection to Proxo, thereby circumventing the problem. If the browser then initiates closure, Proxo would probably also stop waiting for more (that will never arrive) from the 204.

I'm guessing you wouldn't encounter the problem with this other URL used by Gmail:

http://www.google.com/setgmail?zx=

Code:

HTTP/1.1 204 No Content
Content-Type: text/html; charset=UTF-8
Set-Cookie: PREF=ID=...:TM=...:LM=...:GM=1:S=...; path=/; domain=.google.com
Date: Tue, 24 Feb 2009 17:13:39 GMT
Server: gws
Content-Length: 0

The above provides explicit "Content-Length: 0" while the picasaweb server doesn't do that. Here, Proxo would probably pick up on the zero length and realize the 204 response is a done deal.