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

6       LWP::RobotUA - a class for well-behaved Web robots
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SYNOPSIS

9         use LWP::RobotUA;
10         my $ua = LWP::RobotUA->new('my-robot/0.1', 'me@foo.com');
11         $ua->delay(10);  # be very nice -- max one hit every ten minutes!
12         ...
13
14         # Then just use it just like a normal LWP::UserAgent:
15         my $response = $ua->get('http://whatever.int/...');
16         ...
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DESCRIPTION

19       This class implements a user agent that is suitable for robot applica‐
20       tions.  Robots should be nice to the servers they visit.  They should
21       consult the /robots.txt file to ensure that they are welcomed and they
22       should not make requests too frequently.
23
24       But before you consider writing a robot, take a look at
25       <URL:http://www.robotstxt.org/>.
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27       When you use a LWP::RobotUA object as your user agent, then you do not
28       really have to think about these things yourself; "robots.txt" files
29       are automatically consulted and obeyed, the server isn't queried too
30       rapidly, and so on.  Just send requests as you do when you are using a
31       normal LWP::UserAgent object (using "$ua->get(...)", "$ua->head(...)",
32       "$ua->request(...)", etc.), and this special agent will make sure you
33       are nice.
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METHODS

36       The LWP::RobotUA is a sub-class of LWP::UserAgent and implements the
37       same methods. In addition the following methods are provided:
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39       $ua = LWP::RobotUA->new( %options )
40       $ua = LWP::RobotUA->new( $agent, $from )
41       $ua = LWP::RobotUA->new( $agent, $from, $rules )
42           The LWP::UserAgent options "agent" and "from" are mandatory.  The
43           options "delay", "use_sleep" and "rules" initialize attributes pri‐
44           vate to the RobotUA.  If "rules" are not provided, then
45           "WWW::RobotRules" is instantiated providing an internal database of
46           robots.txt.
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48           It is also possible to just pass the value of "agent", "from" and
49           optionally "rules" as plain positional arguments.
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51       $ua->delay
52       $ua->delay( $minutes )
53           Get/set the minimum delay between requests to the same server, in
54           minutes.  The default is 1 minute.  Note that this number doesn't
55           have to be an integer; for example, this sets the delay to 10 sec‐
56           onds:
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58               $ua->delay(10/60);
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60       $ua->use_sleep
61       $ua->use_sleep( $boolean )
62           Get/set a value indicating whether the UA should sleep() if
63           requests arrive too fast, defined as $ua->delay minutes not passed
64           since last request to the given server.  The default is TRUE.  If
65           this value is FALSE then an internal SERVICE_UNAVAILABLE response
66           will be generated.  It will have an Retry-After header that indi‐
67           cates when it is OK to send another request to this server.
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69       $ua->rules
70       $ua->rules( $rules )
71           Set/get which WWW::RobotRules object to use.
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73       $ua->no_visits( $netloc )
74           Returns the number of documents fetched from this server host. Yeah
75           I know, this method should probably have been named num_visits() or
76           something like that. :-(
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78       $ua->host_wait( $netloc )
79           Returns the number of seconds (from now) you must wait before you
80           can make a new request to this host.
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82       $ua->as_string
83           Returns a string that describes the state of the UA.  Mainly useful
84           for debugging.
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SEE ALSO

87       LWP::UserAgent, WWW::RobotRules
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90       Copyright 1996-2004 Gisle Aas.
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92       This library is free software; you can redistribute it and/or modify it
93       under the same terms as Perl itself.
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97perl v5.8.8                       2004-04-06                   LWP::RobotUA(3)
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