LWP::RobotUA - A class for Web Robots
require LWP::RobotUA; $ua = new LWP::RobotUA 'my-robot/0.1', 'firstname.lastname@example.org'; $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.
Set the minimum delay between requests to the same server. The default is 1 minute.
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.
Set/get which WWW::RobotRules object to use.
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. :-(
Returns the number of seconds (from now) you must wait before you can make a new request to this host.
Returns a string that describes the state of the UA. Mainly useful for debugging.
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.