1 HTTP Pipelining with libcurl
2 ============================
6 Since pipelining implies that one or more requests are sent to a server before
7 the previous response(s) have been received, we only support it for multi
12 When using the multi interface, you create one easy handle for each transfer.
13 Bascially any number of handles can be created, added and used with the multi
14 interface - simultaneously. It is an interface designed to allow many
15 simultaneous transfers while still using a single thread. Pipelining does not
16 change any of these details.
20 We've added a new option to curl_multi_setopt() called CURLMOPT_PIPELINING
21 that enables "attempted pipelining" and then all easy handles used on that
22 handle will attempt to use an existing pipeline.
26 - A pipeline is only created if a previous connection exists to the same IP
27 address that the new request is being made to use.
29 - Pipelines are only supported for HTTP(S) as no other currently supported
30 protocol has features resemembling this, but we still name this feature
31 plain 'pipelining' to possibly one day support it for other protocols as
34 - HTTP Pipelining is for GET and HEAD requests only.
36 - When a pipeline is in use, we must take precautions so that when used easy
37 handles (i.e those who still wait for a response) are removed from the multi
38 handle, we must deal with the outstanding response nicely.
40 - Explicitly asking for pipelining handle X and handle Y won't be supported.
41 It isn't easy for an app to do this association. The lib should probably
42 still resolve the second one properly to make sure that they actually _can_
43 be considered for pipelining. Also, asking for explicit pipelining on handle
44 X may be tricky when handle X get a closed connection.
46 - We need options to control max pipeline length, and probably how to behave
47 if we reach that limit. As was discussed on the list, it can probably be
48 made very complicated, so perhaps we can think of a way to pass all
49 variables involved to a callback and let the application decide how to act
50 in specific situations. Either way, these fancy options are only interesting
51 to work on when everything is working and we have working apps to test with.