[hybi] Intermediaries and idle connections (was Re: Technical feedback.)

[Maciej Stachowiak <mjs at apple.com>]

Feedback from server-side implementors is awesome! I'm going to reply to some of these topics separately to put them in separate threads. Let's start with intermediaries and expectation of holding open an idle connection:

On Jan 29, 2010, at 2:55 PM, Greg Wilkins wrote:

Because there is no "buy-in" from intermediaries, we have no
way of knowing how long they will keep open an idle connection.
Because there is no meta-data, we have no idea how long a browser
will keep an idle connection.

So we have to send keep alive messages over the websocket
to make sure it is not closed.  For this we are just using
the /meta/connect message we use for long polling over XHR

That is a valid concern. I think it would be a problem to design a protocol where buy-in from intermediaries is required to deploy at all, because that would greatly delay the deployment timeline. However, you have pointed out a real problem with not knowing how intermediaries will react, namely that you don't know if you need to take special measures to hold the connection open.

I think the right way to approach this, and issues of intermediary participation, is to have optional opt-in from intermediaries. I would like to see a design where at least the SSL version of the WebSocket protocol can operate with no need to change proxies or other intermediaries, but where if proxies or other intermediaries are updated to opt in, there's a way for both the client and server to know that, and to be able to make certain default assumptions, for instance how long the connection is held open even if completely idle. Do you have a concrete proposal?

Regards,

Maciej