LWP::RobotUA

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



NAME
       LWP::RobotUA - a class for well-behaved Web robots

SYNOPSIS
	 use LWP::RobotUA;
	 my $ua = LWP::RobotUA->new(’my-robot/0.1’, ’me@foo.com’);
	 $ua->delay(10);  # be very nice -- max one hit every ten minutes!
	 ...

	 # Then just use it just like a normal LWP::UserAgent:
	 my $response = $ua->get(’http://whatever.int/...’);
	 ...

DESCRIPTION
       This class implements a user agent that is suitable for robot applica-
       tions.  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://www.robotstxt.org/>.

       When you use a LWP::RobotUA object as your user agent, then you do not
       really have to think about these things yourself; "robots.txt" files
       are automatically consulted and obeyed, the server isn’t queried too
       rapidly, and so on.  Just send requests as you do when you are using a
       normal LWP::UserAgent object (using "$ua->get(...)", "$ua->head(...)",
       "$ua->request(...)", etc.), and this special agent will make sure you
       are nice.

METHODS
       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( %options )
       $ua = LWP::RobotUA->new( $agent, $from )
       $ua = LWP::RobotUA->new( $agent, $from, $rules )
	   The LWP::UserAgent options "agent" and "from" are mandatory.	 The
	   options "delay", "use_sleep" and "rules" initialize attributes
	   private to the RobotUA.  If "rules" are not provided, then
	   "WWW::RobotRules" is instantiated providing an internal database
	   of robots.txt.

	   It is also possible to just pass the value of "agent", "from" and
	   optionally "rules" as plain positional arguments.

       $ua->delay
       $ua->delay( $minutes )
	   Get/set the minimum delay between requests to the same server, in
	   minutes.  The default is 1 minute.  Note that this number doesn’t
	   have to be an integer; for example, this sets the delay to 10 sec-
	   onds:

	       $ua->delay(10/60);

       $ua->use_sleep
       $ua->use_sleep( $boolean )
	   Get/set a value indicating whether the UA should sleep() if
	   requests arrive too fast, defined as $ua->delay minutes not passed
	   since last request to the given server.  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
       $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.
	   Yeah I know, this method should probably have been named num_vis-
	   its() 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 use-
	   ful for debugging.

SEE ALSO
       LWP::UserAgent, WWW::RobotRules

COPYRIGHT
       Copyright 1996-2004 Gisle Aas.

       This library is free software; you can redistribute it and/or modify
       it under the same terms as Perl itself.



perl v5.8.8			  2008-04-07		      LWP::RobotUA(3)