GNU/Linux |
CentOS 2.1AS(Slurm) |
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LWP::RobotUA(3pm) |
LWP: :RobotUA − A class for Web Robots
require LWP::RobotUA; $ua = new LWP::RobotUA ’my-robot/0.1’, ’me@foo.com’; $ua->delay(10); # be very nice, go slowly ... # just use it just like a normal LWP::UserAgent $res = $ua->request($req);
This class implements a user agent that is suitable for robot applications. Robots should be nice to the servers they visit. They should consult the /robots.txt file to ensure that they are welcomed and they should not make requests too frequently.
But, before you consider writing a robot take a look at < URL :http://info.webcrawler.com/mak/projects/robots/robots.html>.
When you use a LWP: :RobotUA as your user agent, then you do not really have to think about these things yourself. Just send requests as you do when you are using a normal LWP: :UserAgent and this special agent will make sure you are nice.
The
LWP: :RobotUA is a sub-class of LWP:
:UserAgent and implements the same methods. In addition
the following methods are provided:
$ua = LWP: :RobotUA->new($agent_name,
$from, [$rules])
Your robot’s name and the mail address of the human responsible for the robot (i.e. you) are required by the constructor.
Optionally it allows you to specify the WWW: :RobotRules object to use.
$ua->delay([$minutes])
Set the minimum delay between requests to the same server. The default is 1 minute.
$ua->use_sleep([$boolean])
Get/set a value indicating whether the UA should sleep() if requests arrive too fast (before $ua->delay minutes has passed). The default is TRUE . If this value is FALSE then an internal SERVICE_UNAVAILABLE response will be generated. It will have an Retry-After header that indicates when it is OK to send another request to this server.
$ua->rules([$rules])
Set/get which WWW: :RobotRules object to use.
$ua->no_visits($netloc)
Returns the number of documents fetched from this server host. Yes I know, this method should probably have been named num_visits() or something like that. :−(
$ua->host_wait($netloc)
Returns the number of seconds (from now) you must wait before you can make a new request to this host.
$ua->as_string
Returns a string that describes the state of the UA . Mainly useful for debugging.
the LWP::UserAgent manpage, the WWW::RobotRules manpage
Copyright 1996−2000 Gisle Aas.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
LWP::RobotUA(3pm) |