lwp::robotua(3) [osx man page]

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 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

       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 v5.16.2							    2012-02-11							   LWP::RobotUA(3)

WWW::RobotRules(3)					User Contributed Perl Documentation					WWW::RobotRules(3)

NAME

       WWW::RobotsRules - Parse robots.txt files

SYNOPSIS

	require WWW::RobotRules;
	my $robotsrules = new WWW::RobotRules 'MOMspider/1.0';

	use LWP::Simple qw(get);

	$url = "http://some.place/robots.txt";
	my $robots_txt = get $url;
	$robotsrules->parse($url, $robots_txt);

	$url = "http://some.other.place/robots.txt";
	my $robots_txt = get $url;
	$robotsrules->parse($url, $robots_txt);

	# Now we are able to check if a URL is valid for those servers that
	# we have obtained and parsed "robots.txt" files for.
	if($robotsrules->allowed($url)) {
	    $c = get $url;
	    ...
	}

DESCRIPTION

       This module parses a /robots.txt file as specified in "A Standard for Robot Exclusion", described in
       <http://info.webcrawler.com/mak/projects/robots/norobots.html> Webmasters can use the /robots.txt file to disallow conforming robots access
       to parts of their web site.

       The parsed file is kept in the WWW::RobotRules object, and this object provides methods to check if access to a given URL is prohibited.
       The same WWW::RobotRules object can parse multiple /robots.txt files.

       The following methods are provided:

       $rules = WWW::RobotRules->new($robot_name)
	   This is the constructor for WWW::RobotRules objects.  The first argument given to new() is the name of the robot.

       $rules->parse($robot_txt_url, $content, $fresh_until)
	   The parse() method takes as arguments the URL that was used to retrieve the /robots.txt file, and the contents of the file.

       $rules->allowed($uri)
	   Returns TRUE if this robot is allowed to retrieve this URL.

       $rules->agent([$name])
	   Get/set the agent name. NOTE: Changing the agent name will clear the robots.txt rules and expire times out of the cache.

ROBOTS.TXT
       The format and semantics of the "/robots.txt" file are as follows (this is an edited abstract of
       <http://info.webcrawler.com/mak/projects/robots/norobots.html>):

       The file consists of one or more records separated by one or more blank lines. Each record contains lines of the form

	 <field-name>: <value>

       The field name is case insensitive.  Text after the '#' character on a line is ignored during parsing.  This is used for comments.  The
       following <field-names> can be used:

       User-Agent
	  The value of this field is the name of the robot the record is describing access policy for.	If more than one User-Agent field is
	  present the record describes an identical access policy for more than one robot. At least one field needs to be present per record.  If
	  the value is '*', the record describes the default access policy for any robot that has not not matched any of the other records.

       Disallow
	  The value of this field specifies a partial URL that is not to be visited. This can be a full path, or a partial path; any URL that
	  starts with this value will not be retrieved

ROBOTS.TXT EXAMPLES
       The following example "/robots.txt" file specifies that no robots should visit any URL starting with "/cyberworld/map/" or "/tmp/":

	 User-agent: *
	 Disallow: /cyberworld/map/ # This is an infinite virtual URL space
	 Disallow: /tmp/ # these will soon disappear

       This example "/robots.txt" file specifies that no robots should visit any URL starting with "/cyberworld/map/", except the robot called
       "cybermapper":

	 User-agent: *
	 Disallow: /cyberworld/map/ # This is an infinite virtual URL space

	 # Cybermapper knows where to go.
	 User-agent: cybermapper
	 Disallow:

       This example indicates that no robots should visit this site further:

	 # go away
	 User-agent: *
	 Disallow: /

SEE ALSO

       LWP::RobotUA, WWW::RobotRules::AnyDBM_File

libwww-perl-5.65						    2001-04-20							WWW::RobotRules(3)