Has anyone successfully used the Parallel::ForkManager to download web pages consistently? I am having two primary problems, 1) its not very fast for me (although in testing I am only using 3 to 4 urls so far, I can download many more pages faster without it). Also, the results of my script are inconsistent, sometimes I get all the requested pages, other times the script errors out using NT :( before getting all the pages. I suspect that I am not properly using the “sub wait_all_childs”. I believe that the script quits prematurely even though I have called the “wait” sub. I have inserted it in every place that I can think of and its still inconsistent. I’ve included an excerpt of the code. Please help. The target urls are for testing purposes only. 
########################
use Parallel::ForkManager;
use LWP::Simple;
use LWP::UserAgent ;
use HTTP::Status ;
use HTTP::Request ;
%urls =     (     'drudge'=> 'http://www.drudgereport.com',
              'rush'     => 'http://www.rushlimbaugh.com/home/today.gu
+est.html',
            'yahoo' => 'http://www.yahoo.com',
            'cds' => 'http://www.cdsllc.com/',);
foreach $myURL (sort(values(%urls))) 
{ 
$count++;
print "Count is $count\n";
 $document =  DOCUMENT_RETRIEVER($myURL);
}
sub DOCUMENT_RETRIEVER
{
$myURL=$_[0];
$mit = $myURL;
print "Commencing DOCUMENT_RETRIEVER number $iteration for $mit\n";
print "Iteration is $iteration and Count is $count\n"; 
for  ($iteration = $count; $iteration <= $count; $iteration++)   
{
$name = $iteration;
print "NAME $name\n" ;
my $pm=new Parallel::ForkManager(30);
$pm->start and next;
print "Starting Child Process $iteration for $mit\n" ;
      $ua = LWP::UserAgent->new;
      $ua->agent("$0/0.1 " . $ua->agent);
      $req = new HTTP::Request 'GET' => "$mit";
      $res = $ua->request($req, "$name.html"
          print "Process $iteration Complete\n" ;
           $pm->finish;
           $pm->wait_all_childs;
           print "Waiting on children\n";
}
                   undef $name;
}

[download]

In reply to Parallel Downloads using Parallel::ForkManager or whatever works!!! by jamesluc

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.