www::robotrules::anydbm_file(3) [centos man page]

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

NAME

       WWW::RobotRules::AnyDBM_File - Persistent RobotRules

SYNOPSIS

	require WWW::RobotRules::AnyDBM_File;
	require LWP::RobotUA;

	# Create a robot useragent that uses a diskcaching RobotRules
	my $rules = WWW::RobotRules::AnyDBM_File->new( 'my-robot/1.0', 'cachefile' );
	my $ua = WWW::RobotUA->new( 'my-robot/1.0', 'me@foo.com', $rules );

	# Then just use $ua as usual
	$res = $ua->request($req);

DESCRIPTION

       This is a subclass of WWW::RobotRules that uses the AnyDBM_File package to implement persistent diskcaching of robots.txt and host visit
       information.

       The constructor (the new() method) takes an extra argument specifying the name of the DBM file to use.  If the DBM file already exists,
       then you can specify undef as agent name as the name can be obtained from the DBM database.

SEE ALSO

       WWW::RobotRules, LWP::RobotUA

AUTHORS

       Hakan Ardo <hakan@munin.ub2.lu.se>, Gisle Aas <aas@sn.no>

perl v5.16.3							    2012-02-15					   WWW::RobotRules::AnyDBM_File(3)

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

NAME

       WWW::RobotRules - database of robots.txt-derived permissions

SYNOPSIS

	use WWW::RobotRules;
	my $rules = WWW::RobotRules->new('MOMspider/1.0');

	use LWP::Simple qw(get);

	{
	  my $url = "http://some.place/robots.txt";
	  my $robots_txt = get $url;
	  $rules->parse($url, $robots_txt) if defined $robots_txt;
	}

	{
	  my $url = "http://some.other.place/robots.txt";
	  my $robots_txt = get $url;
	  $rules->parse($url, $robots_txt) if defined $robots_txt;
	}

	# Now we can check if a URL is valid for those servers
	# whose "robots.txt" files we've gotten and parsed:
	if($rules->allowed($url)) {
	    $c = get $url;
	    ...
	}

DESCRIPTION

       This module parses /robots.txt files as specified in "A Standard for Robot Exclusion", at <http://www.robotstxt.org/wc/norobots.html>
       Webmasters can use the /robots.txt file to forbid conforming robots from accessing parts of their web site.

       The parsed files are kept in a WWW::RobotRules object, and this object provides methods to check if access to a given URL is prohibited.
       The same WWW::RobotRules object can be used for one or more parsed /robots.txt files on any number of hosts.

       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://www.robotstxt.org/wc/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.

	  The User-Agent fields must occur before the Disallow fields.	If a record contains a User-Agent field after a Disallow field, that
	  constitutes a malformed record.  This parser will assume that a blank line should have been placed before that User-Agent field, and
	  will break the record into two.  All the fields before the User-Agent field will constitute a record, and the User-Agent field will be
	  the first field in a new record.

       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

       Unrecognized records are ignored.

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: /

       This is an example of a malformed robots.txt file.

	 # robots.txt for ancientcastle.example.com
	 # I've locked myself away.
	 User-agent: *
	 Disallow: /
	 # The castle is your home now, so you can go anywhere you like.
	 User-agent: Belle
	 Disallow: /west-wing/ # except the west wing!
	 # It's good to be the Prince...
	 User-agent: Beast
	 Disallow:

       This file is missing the required blank lines between records.  However, the intention is clear.

SEE ALSO

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

perl v5.12.1							    2009-10-03							WWW::RobotRules(3)