LWP::RobotUA(3pm) User Contributed Perl Documentation LWP::RobotUA(3pm)
LWP::RobotUA - a class for well-behaved Web robots
my $ua = LWP::RobotUA->new('my-robot/0.1', 'meATfoo.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 = $ua->get('http://whatever.int/...');
This class implements a user agent that is suitable for robot
applications. Robots should be nice to the servers they visit. They
should consult the /robots.txt file to ensure that they are welcomed
and they should not make requests too frequently.
But before you consider writing a robot, take a look at
When you use a LWP::RobotUA object as your user agent, then you do not
really have to think about these things yourself; "robots.txt" files
are automatically consulted and obeyed, the server isn't queried too
rapidly, and so on. Just send requests as you do when you are using a
normal LWP::UserAgent object (using "$ua->get(...)", "$ua->head(...)",
"$ua->request(...)", etc.), and this special agent will make sure you
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
It is also possible to just pass the value of "agent", "from" and
optionally "rules" as plain positional arguments.
$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
$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( $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.
Returns a string that describes the state of the UA. Mainly useful
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 v5.10.0 2008-06-17 LWP::RobotUA(3pm)