From: bob <bob@...>
Date: 2004-03-16T12:20:47+09:00
Subject: 1.6 to 1.8 problem?

I'm trying to run this ruby script from a magazine, so there are no typoes,
etc. Here's the error I get...

D:\>ruby test.rb
test.rb:29:in `get_rank_for': Couldn't find sales rank in page
(RuntimeError)
        from test.rb:61:in `value'
        from test.rb:61
        from test.rb:61:in `collect'
        from test.rb:61

-------------------------------------------
and here's the code
-------------------------------------------
#!/usr/bin/eval ruby -w
require 'net/http'
require 'uri'

URLS = [
   ["www.amazon.com",   "/exec/obidos/ASIN/020161622X/o" ],
   ["www.amazon.com",   "/exec/obidos/ASIN/0201710897"   ],
   ["www.amazon.co.jp", "/exec/obidos/ASIN/0201710897"   ],
   ["www.amazon.co.jp", "/exec/obidos/ASIN/4894714531"   ],
   ["www.amazon.co.jp", "/exec/obidos/ASIN/4894712741"   ]
]

# Use HTTP to fetch the page. Most of the code is redirect handling

def get_rank_for(host, path, port=80)

   loop do
      http = Net::HTTP.new(host, port)
      resp = http.get2(path)

      case resp.code

      when "200"
         data  = resp.body

         return $1 if data =~ /Sales Rank:.*?\n?([0-9,]+)/
         return $1 if data =~ /Amazon.co.jp.*?:.*?\n([0-9,]+)/

         raise "Couldn't find sales rank in page"

      when "301", "302", "303"    # retry

         uri = URI.parse(resp['location'])

         host     = uri.host if uri.host
         port     = uri.port if uri.port
         new_path = uri.path if uri.path

         if new_path[0,1] == '/'
            path = new_path
         else
            path = File.join(File.dirname(path), path)
         end

         http.finish if http.active?

      else
         raise "Error #{resp.code} from #{host}#{path}"
      end
   end
end

# Fire off a thread for each request
threads = URLS.collect do |url|
   Thread.new(*url) do |*a_url|
      get_rank_for(*url)
   end
end

# Collect the results as the threads finish
ranks = threads.collect {|t| t.value }

print  Time.now.strftime("%Y/%m/%d %H:%M ")
ranks.each  {|r| printf("%7s", r) }
puts