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

- NAME
- SYNOPSIS
- DESCRIPTION
- METHODS
- SEE ALSO
- COPYRIGHT

# 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 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://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 seconds:

          $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_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.

# SEE ALSO

the LWP::UserAgent manpage, the WWW::RobotRules manpage

# 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.

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