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Table of Contents | ||||
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Introduction
This sample demonstrates how durable or non-durable topics can be created and used in WSO2 Message Broker using the RabbitMQ .NET/C# client. It first introduces a sample .NET client named TopicPublisher
, which is used to publish that publishes messages to a known, created topic in Message Broker, and then . Then it introduces a sample .NET client named TopicConsumer
to listen that listens for messages and print prints message contents to the console.
Prerequisites
To run this code sample, you must download sample:
- Download and add
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- the
RabbitMQ.Client.dll
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- file as a reference in your .NET project. You can download this file from http://www.rabbitmq.com/dotnet.html
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Running the sample
Before running the TopicPublisher class, you must register at least one TopicConsumer binding before sending messages to the topic by doing one of the following:
- Log into WSO2 Message Broker management console and create a topic named 'test-topic' (from the Main menu, choose Topics -> Add).
OR - Run the TopicConsumer class depicted below, which will register a binding to that topic. When you have run the TopicConsumer class, you will see the topic subscription it created is visible in the management console when you choose Topics -> Browse.
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- See Prerequisites to Run the MB Samples for a list of other prerequisites.
Building the sample
Create a TopicConsumer .NET client to receive messages from the
test-topic
topic by adding a class with the following code.Code Block language
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java /* * Copyright (c)
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2015, WSO2 Inc. (http://www.wso2.org) All Rights Reserved. * * WSO2 Inc. licenses this file to you under the Apache License, * Version 2.0 (the "License"); you may not use this file except * in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ using System; using System.Collections.Generic; using System.Linq; using System.Text; using RabbitMQ.Client; namespace MB_
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TopicClient
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{
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class
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TopicConsumer
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{ static void Main(string[] args)
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{
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TopicConsumer
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topicConsumer = new
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TopicConsumer();
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topicConsumer.
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GetMessages(
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); }
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public
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void GetMessages()
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{
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//Setup the connection with the message broker ConnectionFactory factory = new ConnectionFactory(); IProtocol protocol = Protocols.AMQP_0_
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9_
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1; factory.VirtualHost = "/carbon"; factory.UserName = "admin"; factory.Password = "admin"; factory.HostName = "localhost"; factory.Port = 5672; factory.Protocol = protocol;
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using (IConnection conn = factory.CreateConnection())
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{ using (IModel ch = conn.CreateModel()) { // Declare a topic exchange to
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be bound to retrieve messages, here we have used the default topic exchange of WSO2 MB ch.ExchangeDeclare("amq.topic", "topic");
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// Declare a topic name, here we use a non-durable topic. To make it durable use the 2nd parameter as 'true' ch.
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QueueDeclare("
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test-topic", false,
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false,
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false,
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null);
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// Bind the Topic in to the exchange
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Next, execute the following TopicConsumer .NET client, which receives messages from 'test-topic'.
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language | csharp |
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ch.QueueBind("test-topic", "amq.topic", "test-topic"); // Declare a consumer which listens on the messages published to 'test-topic' topic, we need to declare an exclusive subscriber, in order to get this work.
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// The syntax is
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BasicConsume(<queuename>, <noAck>,<consumerTag>, <noLocal>, <exclusive>, <arguments>, <Consumer>)
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QueueingBasicConsumer
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consumer = new
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QueueingBasicConsumer(ch);
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ch.BasicConsume("test-topic", false, "1", false, true, null, consumer);
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while
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(true) { try {
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RabbitMQ.Client.Events.BasicDeliverEventArgs e = (RabbitMQ.Client.Events.BasicDeliverEventArgs)consumer.Queue.Dequeue();
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byte[]
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body =
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e.Body;
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string message = Encoding.UTF8.GetString(body);
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Console.WriteLine("Received Message : " + message);
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ch.BasicAck(e.DeliveryTag, false);
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}
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catch
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(
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OperationCanceledException e) {
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Console.WriteLine(e);
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break;
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}
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}
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}
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} }
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} }
Info At least one TopicConsumer binding should exist before sending messages to the topic. Therefore, this TopicConsumer class should be run before the TopicPublisher class. Alternatively, you can manually create the test-topic topic in the MB Management Console. See Adding Topics for detailed instructions.
Create a TopicPublisher .NET client to send messages to the
test-topic
topic by adding a class with the following code.Code Block language java /* * Copyright (c) 2015, WSO2 Inc. (http://www.wso2.org) All Rights Reserved. * * WSO2 Inc. licenses this file to you under the Apache License, * Version 2.0 (the "License"); you may not use this file except * in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ using System; using System.Collections.Generic; using System.Linq; using System.Text; using RabbitMQ.Client; namespace MB_Topic_Publisher { class TopicPublisher { static void Main(string[] args) {
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TopicPublisher topicPublisher = new
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TopicPublisher(
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); topicPublisher.PublishMessage("Test Message");
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Console.
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WriteLine("
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Message Sent.."); Console.ReadLine(); } public
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void PublishMessage(
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string message) {
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//Setup the connection with the message broker ConnectionFactory factory = new ConnectionFactory(); IProtocol protocol =
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Protocols.AMQP_0_9_1; factory.VirtualHost = "/carbon";
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factory.UserName = "admin";
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factory.Password = "admin"; factory.HostName = "localhost"; factory.Port = 5672; factory.Protocol = protocol; using (IConnection conn = factory.CreateConnection()) { using (IModel ch = conn.CreateModel()) { // Declare a topic exchange to publish messages, here we have used the default topic exchange of WSO2 MB
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ch.ExchangeDeclare("amq.topic", "topic");
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IBasicProperties basicProperties =
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ch.
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CreateBasicProperties(
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); //Setting JMS Message
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ID.
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basicProperties.MessageId = "ID:" + System.Guid.NewGuid().ToString(); //Setting content-type for message as we are sending
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a text message.
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basicProperties.ContentType = "text/plain";
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// Publish the message to the exchange, it will
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send it to the routing key which is our name 'myTopic'.
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// The syntax is ch.BasicPublish(<exchange_name>,
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<topic_name>, <message_properties>,<message_body>) ch.BasicPublish("amq.topic",
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"test-topic", basicProperties, Encoding.UTF8.GetBytes(message)); } } } } }
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Executing the sample
Run this sample from your C# project.