Perl
Must-Match Patterns

You may restrict the spider to only follow links that match any one of a set of "must-match" wildcard patterns. The AddMustMatchPattern can be called repeatedly to add must-match patterns.
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Perl
use chilkat();

$success = 0;

$spider = chilkat::CkSpider->new();

# --------------------------------------------------------------------
# Note: The URLs in this example are no longer valid.
# You should replace the URLs with URLs from a site of your
# own choosing -- preferably your own site if testing.
# (Google's Directory no longer exists.)
# --------------------------------------------------------------------

# First, we'll get the outbound links for a page in the
# Google directory.  Then we'll add some must-match
# and then re-fetch, to see it work...

$spider->Initialize("directory.google.com");
$spider->AddUnspidered("http://directory.google.com/Top/Recreation/Outdoors/Hiking/Backpacking/");

$success = $spider->CrawlNext();

# Display the outbound links

for ($i = 0; $i <= $spider->get_NumOutboundLinks() - 1; $i++) {
    print $spider->getOutboundLink($i) . "\r\n";
}

# The output:
# http://www.backpacker.com
# http://www.cmc.org
# http://www.backpacking.net
# http://www.thebackpacker.com/
# http://www.rei.com/online/store/LearnShareArticlesList?categoryId=Camping
# http://www.trailspace.com/
# http://www.catskillhikes.com/
# http://gorp.away.com/gorp/location/asia/nepal/favpicks.htm
# http://www.backpackinglight.com/cgi-bin/backpackinglight/index.html
# http://www.yetizone.com/
# http://www.backpackingfun.com
# http://www.freezerbagcooking.com/
# http://www.spadout.com/backpacking/
# http://sierrabackpacker.com
# http://www.abovecalifornia.com/
# http://www.personal.psu.edu/faculty/r/p/rpc1/bbb/
# http://www.thebackpackersguide.com
# http://www.journeywest.com/WB/index.html
# http://www.johann-sandra.com/backpackdir.htm
# http://www.geocities.com/amytys/
# http://www.cloudwalkersbasecamp.com
# http://www.netbackpacking.com
# http://members.tripod.com/~stooges/
# http://www.thebackpackingsite.com
# http://www.thruhikers.com/
# http://www.redcompservices.com/AT/
# http://members.aol.com/CMorHiker/backpack
# http://mywebpages.comcast.net/midwestpacker/
# http://www.midwesthiker.com/
# http://www.WeBackpack.com
# http://www.michiganhiker.com
# http://www.host33.com/backpack/
# http://www.wilderness-backpacking.com
# http://www.thetravelmonkey.net
# http://dmoz.org/cgi-bin/add.cgi?where=Recreation/Outdoors/Hiking/Backpacking
# http://dmoz.org/about.html
# http://dmoz.org/cgi-bin/apply.cgi?where=Recreation/Outdoors/Hiking/Backpacking
# http://dmoz.org
# http://dmoz.org/profiles/cdog.html
# http://dmoz.org/profiles/justinwp.html

# Do it again, but this time with avoid patterns.
$spider->Initialize("directory.google.com");
$spider->AddUnspidered("http://directory.google.com/Top/Recreation/Outdoors/Hiking/Backpacking/");

# Add some must-match patterns:
$spider->AddMustMatchPattern("*.com/*");
$spider->AddMustMatchPattern("*.net/*");

# Add some avoid-patterns:
$spider->AddAvoidOutboundLinkPattern("*.mypages.*");
$spider->AddAvoidOutboundLinkPattern("*.personal.*");
$spider->AddAvoidOutboundLinkPattern("*.comcast.*");
$spider->AddAvoidOutboundLinkPattern("*.aol.*");
$spider->AddAvoidOutboundLinkPattern("*~*");

$success = $spider->CrawlNext();

print "-----------------------" . "\r\n";

# Display the outbound links
for ($i = 0; $i <= $spider->get_NumOutboundLinks() - 1; $i++) {
    print $spider->getOutboundLink($i) . "\r\n";
}

# Output:
# http://www.thebackpacker.com/
# http://www.rei.com/online/store/LearnShareArticlesList?categoryId=Camping
# http://www.trailspace.com/
# http://www.catskillhikes.com/
# http://gorp.away.com/gorp/location/asia/nepal/favpicks.htm
# http://www.backpackinglight.com/cgi-bin/backpackinglight/index.html
# http://www.yetizone.com/
# http://www.freezerbagcooking.com/
# http://www.spadout.com/backpacking/
# http://www.abovecalifornia.com/
# http://www.journeywest.com/WB/index.html
# http://www.johann-sandra.com/backpackdir.htm
# http://www.geocities.com/amytys/
# http://www.thruhikers.com/
# http://www.redcompservices.com/AT/
# http://www.midwesthiker.com/
# http://www.host33.com/backpack