jsr339-experts@jax-rs-spec.java.net

[jsr339-experts] Re: How are suspended responses usually managed?

From: Bill Burke <bburke_at_redhat.com>
Date: Sat, 13 Oct 2012 06:36:32 -0400

On 10/12/2012 4:39 PM, Markus KARG wrote:
> Yes this is one form of COMET. And: No, typically the browser will not keep
> the connection open, since this only works if a really lot of constraints
> *all* are fulfilled:
> - The browser, the server, and all intermediate proxies must be http/1.1
> compliant AND implement the persistent connection feature (which is optional
> even in http/1.1), and all these systems must be bug-free.
> - The browser, the server, and all intermediate proxies must intend to
> actually use the persistent connection feature, as even a http/1.1 compliant
> party that fulfils the above constraints in some situations might
> intentionally prefer not to keep the connection open but instead close it
> temporarily and restart another connection later (e. g. if the traffic on
> the party is rather high, but the traffic on that push line is rather low),
> which is a valid implementation of http, unless http/1.0 will be officially
> "forbidden" (which typically will never happen).
> - All of the participating parties must do both above issues at the same
> time. If only one constraint is not fulfilled at any time, the connection
> cannot kept open.
>
> Example: You did your best efforts but for offloading reasons a Squid 3
> proxy is installed -- which does not implement http/1.1 completely and
> chances are high that it has lots of bugs... which foils the browser's and
> server's best efforts.
>
> You see, chances are very low that the connection actually is left open
> (unfortunately).
>

Sounds like you have a *lot* more experience than me with this, but, I
still find it hard to believe that the connection is closed so often. If
this is true, then COMET style apps really aren't much more performing
than vanilla HTTP.

-- 
Bill Burke
JBoss, a division of Red Hat
http://bill.burkecentral.com