Bug 89002 – [Qt] Enable HTTP pipelining

• Status: RESOLVED
• Resolution: INVALID
• Component: Page Loading

[Laszlo Gombos]

Set QNetworkRequest::HttpPipeliningAllowedAttribute for network requests if HTTP pipelining is enabled - see WebContext::setHTTPPipeliningEnabled(). Considered turning on HTTP pipelining by default - after some interoperability testing.

[Keith Kyzivat]

There is good reason not to just turn on HTTP Pipelining by default.  This has been discussed in the past - see bug 64169.

There can be long-lived connections that can hold-up other connections.
For example http long polling, where a connection to a server remains open, without any response being sent by the server until there is an event to deliver, allowing for server->client asynchronous communication [1].  HTTP 1.1 mandates that responses need to be done in the same order as the requests[2], thus the requests that come after the http long polling connection are held up until the server decides to respond, which could be as long as 300 seconds[3], but probably more likely to be somewhere between 30 and 120 seconds to avoid timeouts by proxies.  

Now, servers that do HTTP long-polling are stretching the definition of HTTP, and are definitely not following the spirit of the standard, so we could take the stance that we don't care about that kind of content, and allow it to be broken, but it will make other sites suffer.

Markus Goetz mentions in https://bugs.webkit.org/show_bug.cgi?id=64169#c8 that this could be enabled if we can turn it off for requests emanating from javascript...

1 - http://tools.ietf.org/html/draft-loreto-http-bidirectional-07 synpsis
2 - http://en.wikipedia.org/wiki/HTTP_pipelining
3 - http://tools.ietf.org/html/draft-loreto-http-bidirectional-07#section-5.5

[Laszlo Gombos]

According to http://www.guypo.com/mobile/ios5-top10-performance-changes/ iOS5, Android and Opera Mobile/Mini all have HTTP pipelining enabled.

However it indeed make sense to have this configurable via and experiential API (rather than just turning it on by default all the time).

Realated Mozilla discussion here - https://bugzilla.mozilla.org/show_bug.cgi?id=264354

[Jocelyn Turcotte]

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