app.rb

require 'rubygems'
require 'em-websocket'
require 'redis'
require 'geocoder'
require 'json'
require 'webrick'

$channel = EM::Channel.new
SOCKETS = []
Thread.new do
  EventMachine.run do
    EventMachine::WebSocket.start(:host => '0.0.0.0', :port => 8181) do |ws|
      ws.onopen do
        puts "creating sockets"
        $channel.subscribe { |msg| ws.send msg }
        SOCKETS << ws
      end

      ws.onclose do
        puts "deleting socket"
        $channel.unsubscribe(sid)
        SOCKETS.delete ws
      end
    end
  end
end

Thread.new do
  Geocoder.configure(:lookup => :geocoder_ca, :cache => Redis.new)

  redis = Redis.new
  redis.subscribe('mapdata') do |on|
    on.message do |channel, msg|
      begin
        data = JSON.parse(msg)
        geocoded = Geocoder.search(data["address"])
        data["coords"] = [geocoded[0].longitude, geocoded[0].latitude]
        msg = JSON.generate(data)
        puts "##{channel} -> #{msg}"
        $channel.push msg
      rescue => e
        #Just report the issue and move on
        puts "[RESCUED]: #{e.message}"
      end
    end
  end
end

sleep