Adding the picture resizing consumer

sylvilagus/jruby/lib/sylvilagus/ch04/resize_picture_consumer.rb

@@ -0,0 +1,63 @@
+require 'sylvilagus/init'
+require 'sylvilagus/ch04'
+require 'json'
+require 'rabbitmq-client.jar'
+
+class Sylvilagus::Ch04::ResizePictureConsumer
+  class Consumer < Java::ComRabbitmqClient::DefaultConsumer
+    def handleDelivery(consumer_tag, envelope, properties, body)
+      message = Java::OrgJruby::RubyString.bytes_to_string(body)
+
+      if message == 'quit'
+        channel.basic_cancel(consumer_tag)
+        @done = true
+        return
+      end
+
+      message_hash = JSON.parse(message)
+      resize_picture(message_hash.fetch('image_id'),
+                     message_hash.fetch('image_path'))
+
+      channel.basic_ack(envelope.delivery_tag, false)
+    rescue StandardError
+      channel.basic_nack(envelope.delivery_tag, false)
+    end
+
+    def resize_picture(image_id, image_path)
+      puts "Resizing picture: #{image_id} #{image_path}"
+    end
+
+    def done?
+      !!@done
+    end
+  end
+
+  def main
+    factory = Java::ComRabbitmqClient::ConnectionFactory.new
+    factory.uri = ENV.fetch('SYLVILAGUS_AMQP_URI')
+    @conn = factory.new_connection
+    channel = @conn.create_channel
+    channel.exchange_declare(
+      'upload-pictures', 'fanout', false, true, false, nil
+    )
+    channel.queue_declare('resize-picture', false, true, false, nil)
+    channel.queue_bind('resize-picture', 'upload-pictures', '')
+
+    consumer = Consumer.new(channel)
+    puts "Consuming from 'upload-pictures' exchange"
+    channel.basic_consume('resize-picture', false,
+                          "resize-picture-consumer-#{$$}-#{ENV['HOSTNAME']}",
+                          false, false, nil, consumer)
+    loop do
+      break if consumer.done?
+      sleep 1
+    end
+    return 0
+  ensure
+    @conn.close if @conn
+  end
+end
+
+if $0 == __FILE__
+  exit Sylvilagus::Ch04::ResizePictureConsumer.new.main
+end