phpman > perldoc > LWP::RobotUA(3pm)

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

SYNOPSIS
      use LWP::RobotUA;
      my $ua = LWP::RobotUA->new('my-robot/0.1', 'me AT 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 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 <http://www.robotstxt.org/>.

    When you use an *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:

  new
        my $ua = LWP::RobotUA->new( %options )
        my $ua = LWP::RobotUA->new( $agent, $from )
        my $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.

  delay
        my $delay = $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 seconds:

        $ua->delay(10/60);

  use_sleep
        my $bool = $ua->use_sleep;
        $ua->use_sleep( $boolean );

    Get/set a value indicating whether the UA should "sleep" in LWP::RobotUA 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 a "Retry-After" header that indicates when it is OK to send another
    request to this server.

  rules
        my $rules = $ua->rules;
        $ua->rules( $rules );

    Set/get which *WWW::RobotRules* object to use.

  no_visits
        my $num = $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_visits" or something like that. :-(

  host_wait
        my $num = $ua->host_wait( $netloc )

    Returns the number of *seconds* (from now) you must wait before you can make a new request to
    this host.

  as_string
        my $string = $ua->as_string;

    Returns a string that describes the state of the UA. Mainly useful 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.