Re: [hybi] [whatwg] Web sockets and existing HTTP stacks

[Justin Erenkrantz <[e-mail]>]

On Fri, Dec 18, 2009 at 4:24 PM, Greg Wilkins <[e-mail]> wrote:
> Ian Hickson wrote:
>> On Tue, 17 Nov 2009, Christian Biesinger wrote:
>>> Is it intentional that it is impossible to implement this spec over an
>>> existing HTTP stack, as currently specified?
>>
>> Only to the same extent that it is "intentional" that it's impossible to
>> implement Telnet or SSH over an existing HTTP stack.
>
> Telnet and SSH don't use the HTTP port and don't start with a "legal"
> HTTP request.

Exactly.

> To support websocket in Jetty, we had to use our existing HTTP stack because
> we don't know that the request is a websocket upgrade until we have
> already accepted it and parsed it using our existing HTTP stack.

Ditto - this is a critical problem with the current websocket RFC.  I
would place more credence into the argument that websocket RFC has
nothing at all to do with HTTP if it didn't rely upon the HTTP/1.1
Upgrade semantics.  Either it's related, or it's not.  Let's please
not make the mistake of trying to tunnel protocols thru HTTP firewalls
just because you think it's fun.  You only do so because the semantics
are so similar and there's a lot of code reuse that can be done (which
is the appeal to me of BWTP).

On a server, it's not trivial to switch protocol mechanisms halfway
into the request flow.  Witness all the contortions Apache HTTP Server
has to do when SSL renegotiation is enabled and a request is split
across the renegotiation.  Fun!  Not.  For a client, it's a bit easier
to handle as the client *knows* it intends to upgrade.  But, a real
server won't know that.  -- justin