perl爬虫


云舒
摘要：昨天阴沉了一天，闷在家里做了个简单的爬虫，主要是多线程、队列、Bloom Filter等的使用，算是个demo吧。今天终于下雪了，和LP出去走了走，很有感觉。
#!/usr/bin/perl
use strict;
use warnings;
 
use threads;
use threads::shared;
use Thread::Queue;
use Thread::Semaphore;
 
use Bloom::Filter;
use URI::URL; 
use Web::Scraper;
 
my $max_threads = 30;
my $base_url = $ARGV[0] || http://www.icylife.net/;
my $host = URI->new($base_url)->host;
 
my $queue = Thread::Queue->new( );
my $semaphore = Thread::Semaphore->new( $max_threads );
my $filter = shared_clone( Bloom::Filter->new(capacity => 50000, error_rate => 0.001) );
 
$queue->enqueue( $base_url );
$filter->add( $base_url );
 
while( 1 )
{
 # join all threads which can be joined
 foreach ( threads->list(threads::joinable) )
 {
  $_->join( );
 }
 
 # if there are no url need process.
 my $item = $queue->pending();
 if( $item == 0 )
 {
  # there are no active thread, we finish the job
  if( threads->list(threads::running) == 0 )
  {
   print "All done!n";
   last;
  }
  # we will get some more url if there are some active threads, just wait for them
  else
  {
   sleep 1;
   next;
  }
 }
 
 # if there are some url need process
 while( $semaphore->down )
 {
  threads->create( &ProcessUrl );
 }
}
 
# join all threads which can be joined
foreach ( threads->list() )
{
 $_->join( );
}
 
sub ProcessUrl
{
 my $scraper = scraper
 {
  process //a, links[] => @href;
 };
 
 my $res;
 my $link;
 
 while( my $url = $queue->dequeue_nb() )
 {
  $res = $scraper->scrape( URI->new($url) )->{links};
  #print "there are ".scalar(threads->list(threads::running))." threads, ", $queue->pending(), " urls need process.n";
 
  foreach( @{$res} )
  {
   $link = $_->as_string;
   $link = URI::URL->new($link, $url);
 
   # not http and not https?
   next if( $link->scheme ne http && $link->scheme ne https );
   # another domain?
   next if( $link->host ne $host );
 
   $link = $link->abs->as_string;
 
   if( $link =~ /(.*?)#(.*)/ )
   {
    $link = $1;
   }
 
   next if( $link =~ /.(jpg|png|zip|rar|iso)$/i );
 
   if( ! $filter->check($link) )
   {
    print $filter->key_count(), " ", $link, "n";
    $filter->add($link);
    $queue->enqueue($link);
   }
  }
 }
 $semaphore->up( );
}

补充：综合编程 , 安全编程 ,