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Revision: 1.6
Committed: Fri May 9 22:04:37 2008 UTC (16 years, 1 month ago) by root
Branch: MAIN
CVS Tags: rel-4_7
Changes since 1.5: +3 -0 lines
Log Message:
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File Contents

# User Rev Content
1 root 1.1 =head1 NAME
2    
3     Coro::LWP - make LWP non-blocking - as much as possible
4    
5     =head1 SYNOPSIS
6    
7     use Coro::LWP; # afterwards LWP should not block
8    
9     =head1 DESCRIPTION
10    
11 root 1.6 This module is an L<AnyEvent> user, you need to make sure that you use and
12     run a supported event loop.
13    
14 root 1.1 This module tries to make L<LWP|LWP> non-blocking with respect to other
15     coroutines as much as possible, and with whatever means it takes.
16    
17     LWP really tries very hard to be blocking, so this module had to be very
18     invasive and must be loaded very early to take the proper effect.
19    
20     Here is what it currently does (future versions of LWP might require
21     different tricks):
22    
23     =over 4
24    
25     =item It loads Coro::Select, overwriting the perl C<select> builtin I<globally>.
26    
27     This is necessary because LWP calls select quite often for timeouts and
28     who-knows-what.
29    
30     Impact: everybody else uses this (slower) version of select, too. It should be quite
31     compatible to perls builtin select, though.
32    
33     =item It overwrites Socket::inet_aton with Coro::Util::inet_aton.
34    
35 root 1.2 This is necessary because LWP might (and does) try to resolve hostnames
36     this way.
37 root 1.1
38     Impact: likely little, the two functions should be pretty equivalent.
39    
40 root 1.2 =item It replaces the base class of Net::HTTP, Net::FTP, Net::NNTP.
41 root 1.1
42 root 1.2 This is necessary because LWP does not always use select to see wether
43     a filehandle can be read/written without blocking, so the base class
44     C<IO::Socket::INET> needs to be replaced by C<Coro::Socket>.
45 root 1.1
46     Impact: Coro::Socket is not at all compatible to IO::Socket::INET. While
47     it duplicates some undocumented functionality required by LWP, it does not
48     have all the methods of IO::Socket::INET and might act quite differently
49 root 1.2 in practise. Also, protocols other than the above mentioned will still block,
50     at least some of the time.
51 root 1.1
52     =back
53    
54     All this likely makes other libraries than just LWP not block, but thats
55     just a side effect you cannot rely on.
56    
57     Increases parallelism is not supported by all libraries, some might cache
58     data globally.
59    
60     =cut
61    
62     package Coro::LWP;
63    
64     use strict;
65    
66     use Coro::Select;
67     use Coro::Util;
68     use Coro::Socket;
69    
70     use Socket;
71     use IO::Socket::INET;
72    
73 root 1.2 use Net::HTTP;
74     use Net::FTP;
75     use Net::NNTP;
76    
77 root 1.5 our $VERSION = 4.6;
78 root 1.3
79 root 1.1 *Socket::inet_aton = \&Coro::Util::inet_aton;
80    
81 root 1.2 for (@Net::HTTP::ISA, @Net::FTP::ISA, @Net::NTTP::ISA) {
82     $_ = Coro::LWP::Socket:: if $_ eq IO::Socket::INET::;
83     }
84    
85     package Coro::LWP::Socket;
86    
87     use base Coro::Socket::;
88    
89     sub new {
90     my $self = shift;
91    
92     $self->SUPER::new (@_, partial => 1)
93     }
94    
95     1;
96 root 1.1
97     =head1 AUTHOR
98    
99     Marc Lehmann <schmorp@schmorp.de>
100     http://home.schmorp.de/
101    
102     =cut
103    
104