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Brother monks, I need to make a bunch of LWP::GET requests to grab html, where speed matters. The order the html gets grabbed is unimportant.

From browsing around PM, I think I could do this faster using forking, threading, Parallel::UserAgent, or some combination thereof. But which combination? To complicate matters, I'm on windows with ActiveState. Ideally I'd like to have a program that's OS independent, works on windows and unix.

But I'm a total threading newbie. Can somebody point me in the right direction? A program that seemed like it could be adapted to my task was merlyn's paralell stress tester but I'm just wondering if there's an easier/cleaner/faster way. This was back in 1998, and Merlyn wrote then that Parallel::UserAgent should be folded into the normal LWP library, but I don't think this has happened... has it?

use strict; use warnings; use LWP::UserAgent; my $output_file = "output.txt"; my %html; # Localtime printouts check only # how long it takes to download the html, # not do the printing print scalar localtime , "\n"; while (<DATA>) { $html{$_} = get_html($_); } print scalar localtime , "\n"; #output: #Thu Mar 3 13:10:59 2005 #Thu Mar 3 13:11:16 2005 # ~ 17 seconds #print out the html as a sanity check. open F, "> output.txt" or die "couldn't open output file"; foreach (keys %html) { print F "$_:\n" . $html{$_}; } close F; sub get_html { my $url = shift; my $ua = LWP::UserAgent->new; $ua->agent('Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)'); $ua->timeout(30); my $request = HTTP::Request->new('GET', "$url"); my $www = $ua->request($request); my $html; unless ( $www->is_success ) { # Attempt to get html failed. die "Failed to get html for $url" } else { # html retrieved ok. $html = $www->content; } return $html; } __DATA__ http://www.google.com http://www.yahoo.com http://www.amazon.com http://www.ebay.com http://www.perlmonks.com http://news.yahoo.com http://news.google.com http://www.msn.com http://www.slashdot.org http://www.indymedia.org
takes 16 seconds to print ten web pages to a file.

Is there a better/faster way? Can someone point me towards the light? Thanks!

UPDATE: I followed inman's tip and wound up with

#! /usr/bin/perl -w use strict; use warnings; use LWP; use threads; use Thread::Queue; my $query ="perl"; my $dataQueue = Thread::Queue->new; my $threadCount = 0; my $output_file = "output.txt"; my %html; my $start = time; while (<DATA>) { chomp; #s/^\s+//; s/\s+$//; #my ($engine, $url) = split /\s+/; #next unless $url; my $url = $_; my $thr = threads->new(\&get_html, $url); $thr->detach; $threadCount ++; } while ($threadCount) { my $url = $dataQueue->dequeue; $html{$url} = $dataQueue->dequeue; $threadCount --; } print "done in " . scalar ( time - $start) . " seconds."; #print out the html as a sanity check. open F, "> output.txt" or die "couldn't open output file"; foreach (keys %html) { print F "$_:\n" . $html{$_}; } close F; sub get_html { #my $engine = shift; my $url = shift; my $ua = LWP::UserAgent->new; $ua->agent('Mozilla/5.0'); $ua->timeout(10); $ua->env_proxy; my $response = $ua->get($url); if ($response->is_success) { $dataQueue->enqueue($url, $response->content); } else { $dataQueue->enqueue($url, $response->message); } } __DATA__ http://www.google.com http://www.yahoo.com http://www.amazon.com http://www.ebay.com http://www.perlmonks.com http://news.yahoo.com http://news.google.com http://www.msn.com http://www.slashdot.org http://www.indymedia.org
which ran in 8-14 seconds. A bit faster than what I started out with, but not as fast as what I was getting with BrowserUK's method below. Also, I would sometimes get "a thread exited while two other threads were running" warnings, not sure what this means. This never happened running BrowserUK's code.

I also agree with BrowserUK that 10 isn't enough to benchmark, so at some point I'll try this out grabbing 50 or 100 web pages at a time.


In reply to What is the fastest way to download a bunch of web pages? by tphyahoo

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