icleversoft
10/12/2012 - 11:20 AM

EventMachine

EventMachine

websocket.html
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<!DOCTYPE html>
<head>
  <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" type="text/javascript"></script>
  <script type="text/javascript">
    $(document).ready(function() {
      var container = $('.container');
      
      var addTweetToPage = function(language, tweet) {
        var id = 'tweet' + language;
        if ($('#'+id).length == 0) {
          container.append('<div id="'+id+'"><h1>'+language+'</h1></div>')
        }
        $('#'+id).append('<div class="tweet">'+tweet+'</div>');
      };
      
      var socket = new WebSocket('ws://0.0.0.0:8080/');

      socket.onopen = function() {
        console.log("Socket opened");
      };

      socket.onmessage = function(message) {
        var info = JSON.parse(message.data);
        console.log(info.lang, info.tweet);
        addTweetToPage(info.lang, info.tweet);
      };

      socket.onclose = function() {
        console.log("Socket closed");
      };
    })
  </script>
</head>

<body>
  <div class="container"></div>
</body>
twitter_stream.rb
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require 'em-http'
require 'json'

class TwitterStream
  URL = 'http://stream.twitter.com/1/statuses/filter.json'
  
  def initialize(username, password, term)
    @username, @password = username, password
    @term = term
    @callbacks = []
    @buffer = ""
    listen
  end
  
  def ontweet(&block)
    @callbacks << block
  end
  
  private
  
  def listen
    http = EventMachine::HttpRequest.new(URL).post({
      :head => { 'Authorization' => [@username, @password] },
      :query => { "track" => @term }
    })
    
    http.stream do |chunk|
      @buffer += chunk
      process_buffer
    end
  end
  
  def process_buffer
    while line = @buffer.slice!(/.+\r\n/)
      tweet = JSON.parse(line)

      @callbacks.each { |c| c.call(tweet['text']) }
    end
  end
end
server.rb
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require 'rubygems'
require 'eventmachine'
require 'em-websocket'
require 'twitter_stream'
require 'language_detector'

TWITTER_USERNAME = ''
TWITTER_PASSWORD = ''
TWITTER_TERM = 'twitter'

EM.run {
  websocket_connections = []
  
  EM::WebSocket.start(:host => "0.0.0.0", :port => 8080) do |ws|
    ws.onopen {
      puts "Websocket connection opened"
      websocket_connections << ws
    }
    ws.onclose {
      puts "Websocket connection closed"
      websocket_connections.delete(ws)
    }
  end
  
  stream = TwitterStream.new(TWITTER_USERNAME, TWITTER_PASSWORD, TWITTER_TERM)
  stream.ontweet { |tweet|
    LanguageDetector.new(tweet).callback { |lang|
      puts "New tweet in #{lang}: #{tweet}"
      
      websocket_connections.each do |socket|
        socket.send(JSON.generate({
          :lang => lang,
          :tweet => tweet
        }))
      end
    }
  }
}
language_detector.rb
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require 'em-http'
require 'json'

class LanguageDetector
  URL = "http://www.google.com/uds/GlangDetect"
  
  include EM::Deferrable
  
  def initialize(text)
    request = EM::HttpRequest.new(URL).get({
      :query => {:v => "1.0", :q => text}
    })
    
    # This is called if the request completes successfully (whatever the code)
    request.callback {
      begin
        if request.response_header.status == 200
          info = JSON.parse(request.response)["responseData"]
          if info['isReliable']
            self.succeed(info['language'])
          else
            self.fail("Language could not be reliably determined")
          end
        else
          self.fail("Call to fetch language failed")
        end
      rescue
        puts request.response
        self.fail
      end
    }
    
    # This is called if the request totally failed
    request.errback {
      self.fail("Error making API call")
    }
  end
end
README.md
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  • Rendered
  • Source

Getting started

First add your twitter username and password. Then server.rb and once it's started open websocket.html in your browser. You should see some tweets appear. If not take a look at the javascript console.