Thx， got it.
2013/12/31 Simone Bordet <[email protected]> > Hi, > > On Mon, Dec 30, 2013 at 5:20 PM, Ryan Young <[email protected]> > wrote: > > I mean at client side we may need to face the case: > > > > the resource is being pushed, but the data has not yet arrived > > > > So I wonder how the client deal with this case to avoid sending redundant > > "GET" for resource that is being pushed. > > This is more a question for browser implementers, but I'll give you my > version. > > The client is about to ask for a secondary resource B that may be pushed. > It first checks B in its cache. If present and valid, it uses that > (and possibly discards the push). > Then, it looks at the push cache built for the primary resource. If B > is present and valid, it uses that. > If B is going to be pushed, but not there yet (your case above), it > waits for it. When it is arrived it just renders it on the viewport. > Otherwise it issues a GET (which may also contain if-modified-since > headers, etc.). > > There always is a race between what is being pushed and the GET from the > client. > The server can optimize that and send the pushed headers before or > concurrently with the data for the primary resource. > Jetty does this, and along with other SPDY improvements, there is a > good chance that the reply and the pushed headers are sent in a single > write, probably even in the same TCP packet. > This reduces the window between the client issuing GETs and the server > pushing resources, since the client will know pretty early that pushed > data will arrive, and can avoid to GET it. > > SPDY push is not a fool proof mechanism to push resources; however, in > most cases provides a sensible perceived improvement in page > "rendering", from our experience. > > -- > Simone Bordet > ---- > http://cometd.org > http://webtide.com > http://intalio.com > Developer advice, training, services and support > from the Jetty & CometD experts. > Intalio, the modern way to build business applications. > _______________________________________________ > jetty-users mailing list > [email protected] > https://dev.eclipse.org/mailman/listinfo/jetty-users >
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