1LWP(3)                User Contributed Perl Documentation               LWP(3)
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NAME

6       Coro::LWP - make LWP non-blocking - as much as possible
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SYNOPSIS

9        use Coro::LWP; # afterwards LWP should not block
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ALTERNATIVES

12       Over the years, a number of less-invasive alternatives have popped up,
13       which you might find more acceptable than this rather invasive and
14       fragile module. All of them only support HTTP (and sometimes HTTPS).
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16       AnyEvent::HTTP
17           Works fine without Coro. Requires using a very different API than
18           LWP. Probably the best choice iff you can do with a completely
19           different event-based API.
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21       LWP::Protocol::AnyEvent::http
22           Makes LWP use AnyEvent::HTTP. Does not make LWP event-based, but
23           allows Coro threads to schedule unimpeded through its AnyEvent
24           integration.
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26           Lets you use the LWP API normally.
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28       LWP::Protocol::Coro::http
29           Basically the same as above, distinction unclear. :)
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31       AnyEvent::HTTP::LWP::UserAgent
32           A different user agent implementation, not completely transparent
33           to users, requires Coro.
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DESCRIPTION

36       This module is an AnyEvent user, you need to make sure that you use and
37       run a supported event loop.
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39       This module tries to make LWP non-blocking with respect to other
40       coroutines as much as possible, and with whatever means it takes.
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42       LWP really tries very hard to be blocking (and relies on a lot of
43       undocumented functionality in IO::Socket), so this module had to be
44       very invasive and must be loaded very early to take the proper effect.
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46       Note that the module AnyEvent::HTTP might offer an alternative to the
47       full LWP that is designed to be non-blocking.
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49       Here is what it currently does (future versions of LWP might require
50       different tricks):
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52       It loads Coro::Select, overwriting the perl "select" builtin globally.
53           This is necessary because LWP calls select quite often for timeouts
54           and who-knows-what.
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56           Impact: everybody else uses this (slower) version of select, too.
57           It should be quite compatible to perls builtin select, though.
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59       It overwrites Socket::inet_aton with Coro::Util::inet_aton.
60           This is necessary because LWP might (and does) try to resolve
61           hostnames this way.
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63           Impact: some code might not expect coroutine semantics, for
64           example, when you fork you might prefer the blocking variant
65           because other coroutines shouldn't actually run.
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67       It replaces the base class of Net::HTTP, Net::FTP, Net::NNTP.
68           This is necessary because LWP does not always use select to see
69           whether a filehandle can be read/written without blocking, so the
70           base class "IO::Socket::INET" needs to be replaced by
71           "Coro::Socket".
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73           Impact: Coro::Socket is not at all compatible to IO::Socket::INET.
74           While it duplicates some undocumented functionality required by
75           LWP, it does not have all the methods of IO::Socket::INET and might
76           act quite differently in practise. Also, protocols other than the
77           above mentioned will still block, at least some of the time.
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79       All this likely makes other libraries than just LWP not block, but
80       that's just a side effect you cannot rely on.
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82       Increases parallelism is not supported by all libraries, some might
83       cache data globally.
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AUTHOR/SUPPORT/CONTACT

86          Marc A. Lehmann <schmorp@schmorp.de>
87          http://software.schmorp.de/pkg/Coro.html
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91perl v5.30.1                      2020-01-29                            LWP(3)
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