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