Publishing and Receiving Messages from a Queue

This sample demonstrates how persistent queues can be created and used in Message Broker using the RabbitMQ .NET/C# client. It first introduces a sample .NET client named QueuePublisher, which is used to publish messages to a known, created queue in WSO2 Message Broker. Then it introduces a sample .NET client named QueueConsumer to receive messages and print message content to the console.

Prerequisites

In order to run this sample:

• Download and add the RabbitMQ.Client.dll file as a reference in your .NET project. You can download the file from http://www.rabbitmq.com/dotnet.html or from the WSO2 repository.
• See Prerequisites to Run the MB Samples for a list of other prerequisites.

Building the sample

1. Create a QueueConsumer .NET client to receive messages from the test-queue queue by adding a class with the following code.

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Text;
   using RabbitMQ.Client;
     
     
   namespace QueueConsumer
   {
       class QueueConsumer
       {
           static void Main(string[] args)
           {
               QueueConsumer qConsumer = new QueueConsumer();
               qConsumer.GetMessage();
           }
     
           public void GetMessage()
           {
               //Setup the connection with the message broker
               ConnectionFactory factory = new ConnectionFactory();
               IProtocol protocol = Protocols.AMQP_0_9_1;
               factory.VirtualHost = "/carbon";
               factory.UserName = "admin";
               factory.Password = "admin";
               factory.HostName = "localhost";
               factory.Port = 5672;
               factory.Protocol = protocol;
               using (IConnection conn = factory.CreateConnection())
               {
                   using (IModel ch = conn.CreateModel())
                   {
                       //Declare a queue to retrieve messages.
                       ch.QueueDeclare("test-queue", true, false, false, null);
                       //Create the binding between queue and the exchance
                       ch.QueueBind("test-queue", "amq.direct", "test-queue");
                       QueueingBasicConsumer consumer = new QueueingBasicConsumer(ch);
                       ch.BasicConsume("test-queue", false, consumer);
   
                       while (true)
                       {
                           try
                           {
                               RabbitMQ.Client.Events.BasicDeliverEventArgs e = (RabbitMQ.Client.Events.BasicDeliverEventArgs)consumer.Queue.Dequeue();
                               byte[] body = e.Body;
                               string message = Encoding.UTF8.GetString(body);
                               Console.WriteLine("Received Message : " + message);
                               ch.BasicAck(e.DeliveryTag, false);
                           }
                           catch (OperationCanceledException e)
                           {
                               Console.WriteLine(e);
                               break;
                           }
                       }
                   }
               }
           }        
       }
   }

   At least one QueueConsumer binding should exist before sending messages to the queue. Therefore, this QueueConsumer class should be run before the QueuePublisher class. Alternatively, you can manually create the test-queue queue in the MB Management Console. See Adding Queues for detailed instructions.

2. Create a QueuePublisher .NET client to send messages to the test-queue queue by adding a class with the following code.

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Text;
   using RabbitMQ.Client;
     
   namespace RabbitMQ
   {
       class QueuePublisher
       {
           static void Main(string[] args)
           {
               QueuePublisher publisher=new QueuePublisher();
               publisher.PublishMessage("This is a Test Message");
               Console.WriteLine("Message Sent");
               
               Console.ReadLine();
           }
    
     
           public void PublishMessage(string message)
           {
               //Setup the connection with the message broker
               ConnectionFactory factory = new ConnectionFactory();
               IProtocol protocol = Protocols.AMQP_0_9_1;
               factory.VirtualHost = "/carbon";
               factory.UserName = "admin";
               factory.Password = "admin";
               factory.HostName = "localhost";
               factory.Port = 5672;
               factory.Protocol = protocol;
               using (IConnection conn = factory.CreateConnection())
               {
                   using (IModel ch = conn.CreateModel())
                   {
                       IBasicProperties basicProperties = ch.CreateBasicProperties();
                       //Setting JMS Message ID.
                       basicProperties.MessageId = "ID:" + System.Guid.NewGuid().ToString();
                       //Setting content-type for message as we are sending a text message.
                       basicProperties.ContentType = "text/plain";
                       //Declare the exchange for the publisher.Here the exchange type is direct.
                       ch.ExchangeDeclare("amq.direct", "direct");
                       //Publish the message
                       ch.BasicPublish("amq.direct", "test-queue", basicProperties, Encoding.UTF8.GetBytes(message));
                   }
               }
           }
       }
   }

Executing the sample

Run this sample from your C# project.