Good news: Tomcat team has decided that they will use chunked-encoding also when the request includes a "Connection: close". So in future versions of Tomcat, there will be no need for http-pretend-keepalive
http://marc.info/?l=tomcat-dev&m=127066772025778&w=2 Willy, maybe you can include in the documentation of "http-pretend-keepalive" something like this: "This option is recommended when using http-server-close for backends running: Tomcat 5.5.28 or below, Tomcat 6.0.26 or below, or Jetty.". 2010/4/1 Óscar Frías Barranco <ofr...@gmail.com> > I have "forwarded" the issue (with your explanation, thank you Willy) to > Tomcat developers mailing list and it has got several replies, maybe you > want to participate: > > http://marc.info/?t=127011623400002&r=1&w=2 > > Regards, > Óscar > > > > 2010/4/1 Willy Tarreau <w...@1wt.eu> > > Hi Oscar, >> >> On Wed, Mar 31, 2010 at 07:15:34PM +0200, Óscar Frías Barranco wrote: >> > I have been looking at Tomcat source code and apparently it looks like >> there >> > is an easy fix. >> >> That's good news ! >> >> > Here is the class where the logic is implemented: >> > >> http://svn.apache.org/repos/asf/tomcat/trunk/java/org/apache/coyote/http11/Http11Processor.java >> > >> > And this is the patch that I have generated: >> > >> > Index: java/org/apache/coyote/http11/Http11Processor.java >> > =================================================================== >> > --- java/org/apache/coyote/http11/Http11Processor.java Tue Mar 09 >> > 18:09:50 CET 2010 >> > +++ java/org/apache/coyote/http11/Http11Processor.java Tue Mar 09 >> > 18:09:50 CET 2010 >> > @@ -1547,7 +1547,7 @@ >> > (outputFilters[Constants.IDENTITY_FILTER]); >> > contentDelimitation = true; >> > } else { >> > - if (entityBody && http11 && keepAlive) { >> > + if (entityBody && http11) { >> > outputBuffer.addActiveFilter >> > (outputFilters[Constants.CHUNKED_FILTER]); >> > contentDelimitation = true; >> >> Indeed, eventhough I generally don't read Java code, this one >> looks obviously right :-) >> >> > I would like to send this to Tomcat mailing list, but if we want this >> change >> > to be implemented I think that we must explain which are the benefits of >> > using chunked encoding also when not using keepalive. >> > Willy, could you help me with this ? >> >> Yes, I will try :-) >> >> Chunked transfer-encoding is an alternative to content-length, for >> use when the content-length cannot initially be determined. While >> it is mandatory to have either of them to support keep-alive, its >> use is not restricted to keep-alive and one useful immediate benefit >> of using it is to allow a client to distinguish a connection abort >> from a complete response in order to avoid storing truncated data. >> >> Another useful case is when a reverse-proxy is installed in front >> of the server, and this reverse proxy tries to maintain keep-alive >> connections with the clients and intends to close the connections >> with the servers (like apache 1.3, haproxy, and I think nginx). >> The lack of content-length and chunked encoding prevents the proxy >> from keeping client connections alive. The "connection: close" >> sent by the proxy to the server only indicates that the proxy will >> send just one request to the server, not that it does not care >> about the response length. The same is true when that proxy caches. >> Without any content-length nor chunked encoding, the cache could >> store and distribute truncated response believing they are complete, >> while this would not happen with chunked encoding because the cache >> will be able to know it has not seen the end of the response. >> >> Hoping this helps ! >> Anyway, if Cyril's workaround works, I'll merge it because Tomcat >> is probably not the only component affected by that. That way we'd >> be able to enable it when needed. >> >> Willy >> >> >
