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47 lines
2.1 KiB
47 lines
2.1 KiB
5 months ago
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2011/04/20 - List of keep-alive / close options with associated behaviours.
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PK="http-pretend-keepalive", HC="httpclose", SC="http-server-close",
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FC = "forceclose".
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0 = option not set
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1 = option is set
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* = option doesn't matter
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Options can be split between frontend and backend, so some of them might have
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a meaning only when combined by associating a frontend to a backend. Some forms
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are not the normal ones and provide a behaviour compatible with another normal
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form. Those are considered alternate forms and are marked "(alt)".
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FC SC HC PK Behaviour
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0 0 0 X tunnel mode
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0 0 1 0 passive close, only set headers then tunnel
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0 0 1 1 forced close with keep-alive announce (alt)
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0 1 0 0 server close
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0 1 0 1 server close with keep-alive announce
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0 1 1 0 forced close (alt)
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0 1 1 1 forced close with keep-alive announce (alt)
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1 * * 0 forced close
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1 * * 1 forced close with keep-alive announce
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At this point this results in 4 distinct effective modes for a request being
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processed :
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- tunnel mode : Connection header is left untouched and body is ignored
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- passive close : Connection header is changed and body is ignored
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- server close : Connection header set, body scanned, client-side keep-alive
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is made possible regardless of server-side capabilities
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- forced close : Connection header set, body scanned, connection closed.
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The "close" modes may be combined with a fake keep-alive announce to the server
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in order to workaround buggy servers that disable chunked encoding and content
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length announces when the client does not ask for keep-alive.
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Note: "http-pretend-keepalive" alone has no effect. However, if it is set in a
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backend while a frontend is in "http-close" mode, then the combination of
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both will result in a forced close with keep-alive announces for requests
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passing through both.
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It is also worth noting that "option httpclose" alone has become useless since
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1.4, because "option forceclose" does the right thing, while the former only
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pretends to do the right thing. Both options might get merged in the future.
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