NAME
    URPL::Prepare -- prepare hostname for URBL domain lookup

SYNOPSIS
      require URBL::Prepare;

      my $ubp = new URBL::Prepare;

      $tlds = $blessed->cachetlds($localfilelistptr);
      $whitelist = $blessed->cachewhite($localfilelistptr);
      $domain = $blessed->urbldomain($hostname);
      $response_code = $proto->loadcache($url,$localfile);
      ($response,$message) = $proto->loadcache($url,$localfile);
      $rv = $blessed->urblblack($hostname);
      $rv = $blessed->urblwhite($hostname);

DESCRIPTION
    * my $urbl = new URBL::Prepare;
      This method returns a blessed reference to an empty hash.

      For use with other modules:

        require URBL::Prepare;

        @ISA = qw(URBL::Prepare);

URBL Preparation for lookup methods
    The following three methods are for facilitating URBL lookups.

      SEE:  http://www.uribl.com/about.shtml
      and   http://www.surbl.org/guidelines

    * $tldlist = $blessed->cachetlds($localfilelistptr);
      This method opens local files in "file list" and extracts the tld's
      found therein.

        input:        ptr to array of local/file/path/names
        return:       array ptr to list of tld's

      NOTE: place level 3 tld's ahead of level 2 tld's

    * $whitelist = $blessed->cachewhite($localfilelistptr);
      This method opens local file(s) in "file list" and extracts the
      domains found therein.

        See http://wiki.apache.org/spamassassin/DnsBlocklists         and
        http://spamassasin.googlecode.com/svn-history/r6/trunk/share/spamassassin/

      Note:: these URL's may change

        input:        ptr to array of local/file/path/names
        return:       array ptr to whitelist domain names

    * $blacklist = $blessed->cacheblack($localfilelistptr);
      This method opens local file(s) in "file list" and extracts the
      domains found therein. The domains may be space seperated many to a
      line.

        input:        ptr to array of local/file/path/names
        return:       ptr to blacklist domain names

    * $domain = $blessed->urbldomain($hostname)
      This method extracts a domain name to check against an SURBL. If the
      hostname is whitelisted, the return value is false, otherwise a domain
      name is returned.

        input:        hostname
        return:       false if whitelisted
              else    domain to check against SURBL

      NOTE: optionally white or tld testing will be bypassed if the pointer
      is undefined or points to an empty array.

    * $rv = $blessed->urblblack($hostname)
      This method check if a hostname is found within the local black
      list(s).

        input:        hostname
        return:       domain found, else false

    * $rv = $blessed->urbwhite($hostname)
      This method check if a hostname is found within the local white list.

        input:        hostname
        return:       domain found, else false

    * $response_code = $proto->loadcache($url,$localfile);
    * ($response,$message) = $proto->loadcache($url,$localfile);
      This method uses LWP::UserAgent::mirror to conditionally retrieve
      files to fill local cache with WHITELIST and TLD names. The response
      code is the result returned by the HTTP fetch and should be one of 200
      or 304. At the time this module was released the files were as
      follows:

        WHITE LIST URL
        http://spamassasin.googlecode.com/svn-history/r6/trunk/share/spamassassin/25_uribl.cf

      and

        TLDLIST URL (include some known abusive tlds)
        http://george.surbl.org/three-level-tlds
        http://george.surbl.org/two-level-tlds

        input:        path/name/for/localfile
        return:       http response code,
                      response message

      In scalar context only the http response code is returned. In array
      context the numeric response code and a related text message are
      returned.

        200   OK              file cached
        304   Not Modified    file is up-to-date

      Any other response code indicates and error.

        Usage:
        $rv = URBL::Prepare->loadcache($url,$localfile);

APPLICATION EXAMPLES
    This example shows how to include URBL::Prepare in another module

      #!/usr/bin/perl
      package = Some::Package

      use vars qw(@ISA);
      require URBL::Prepare;

      @ISA = qw( URBL::Prepare );

      sub new {
        my $proto = shift;
        my $class = ref $proto || $proto || __PACKAGE__;
        my $methodptr = {
            ....
        };
        bless $methodptr, $class;
      }
      ... package code ...
      1;

      ...end
    ......................

      #!/usr/bin/perl
      # my application
      #
      use Net::DNS::Dig;
      use Some::Package;

      my $dig = new Net::DNS::Dig;
      my $sp = new Some::Package;
      #
      # initialiaze URBL::Prepare
      #
      $sp->cachewhite($localwhitefiles);
      $sp->cachetlds($localtldfiles);

      # set multi.surbl.org bit mask
      #     2 = comes from SC
      #     4 = comes from WS
      #     8 = comes from PH
      #     16 = comes from OB (OB is deprecated as of 22 October 2012.)
      #     16 = comes from MW (MW active as of 1 May 2013.)
      #     32 = comes from AB
      #     64 = comes from JP

      # test as: surbl-org-permanent-test-point.com.multi.surbl.org

      my $mask = 0xDE;

        ... application ...
        ... generates   ...
        ... hostname    ...

      my $domain = $sp->urbldomain($hostname)

      my $response = $dig->for($hostname . 'multi.surbl.org')
            if $domain;     # if not whitelisted

      # if an answer is returned
      if ($domain && $response->{HEADER}->{ANCOUNT}) {
        # get packed ipV4 answer
        my $answer = $response->{ANSWER}->[0]->{RDATA}->[0];
        if ($mask & unpack("N",$answer)) {
            # answer is found in selected surbl list
        } else {
            # answer not found in selected surbl list
        }
      }
      # domain not found in surbl

      ...end

    This is an example of a script file to keep the whitelist and tldlist
    current. Run as a cron job daily.

      #!/usr/bin/perl
      #
      # cache refresh cron job
      #
      require URBL::Prepare;

      my $whiteurl =
      'http://spamassasin.googlecode.com/svn-history/r6/trunk/share/spamassassin/25_uribl.cf';

      my $tld2url = 'http://george.surbl.org/two-level-tlds';
      my $tld3url = 'http://george.surbl.org/three-level-tlds';

      my $cachedir  = './cache';
      my $lvl2file  = $cachedir .'/level2';
      my $lvl3file  = $cachedir .'/level3';
      my $whtfile   = $cachedir .'/white';

      mkdir $cachedir unless -d $cachedir;

      URBL::Prepare->loadcache($whiteurl,$whtfile);
      URBL::Prepare->loadcache($tld2url,$lvl2file);
      URBL::Prepare->loadcache($tld3url,$lvl3file);

AUTHOR
    Michael Robinton <michael@bizsystems.com>

COPYRIGHT
        Copyright 2013-2014, Michael Robinton <michael@bizsystems.com>

    This program is free software; you may redistribute it and/or modify it
    under the same terms as Perl itself.

    This program is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See also:
    the LWP::Request manpage, the Net::DNS::Dig manpage

