From: Richard Conroy <richard.conroy@...>
Date: 2006-12-07T23:48:19+09:00
Subject: Odd result when attempting to use Mechanize in parallel with Threads

I wrote a simple tool to iterate a network to try and find web servers
running on specific ports. We have a lot of devices & software with a
web UI, and I thought that this would be a handy way to find them,
and even tell what they are.

I thought this would be a handy coding project too, and a good way to
cut my teeth on Ruby threads, and build up some usage with
Mechanize.

BTW I am running this on *Windows XP*.

However my code is quite obviously executing this serially. Is there
something obviously wrong with my code below? (results after
code snippet). I am aware this could make my machine choke from
thread overkill, but I wanted to get it working in parallel first.
Perhaps Mechanize instances have some shared elements?

============================
require 'mechanize'

threads = Array.new
puts "sweep of 153.200.72.* segment http ports"
(1..254).each do |ran|
	threads << Thread.new(ran) { |r|
		agent = WWW::Mechanize.new
		agent.user_agent_alias = 'Windows Mozilla'
		ports = [80,8080]
		ports.each do |p|
			begin
				page = agent.get("http://153.200.72."+r.to_s+":"+p.to_s)
				puts "153.200.72."+r.to_s+":"+p.to_s+" - "+page.title
			rescue
				puts "153.200.72."+r.to_s+":"+p.to_s+" - NOTHING"
			end
		end
	}
	threads.each { |aThread|  aThread.join }
end
============================

153.200.72.10:80 - NOTHING
153.200.72.10:8080 - NOTHING
153.200.72.11:80 - NOTHING
153.200.72.11:8080 - NOTHING
153.200.72.12:80 - NOTHING
153.200.72.12:8080 - NOTHING
153.200.72.13:80 - NOTHING
153.200.72.13:8080 - NOTHING
153.200.72.14:80 - NOTHING
153.200.72.14:8080 - NOTHING
153.200.72.15:80 - NOTHING
153.200.72.15:8080 - NOTHING
153.200.72.16:80 - NOTHING
153.200.72.16:8080 - NOTHING
153.200.72.17:80 - NOTHING
153.200.72.17:8080 - NOTHING