How to Build a Simple Message Queue in Node.js and RabbitMQ

How to Build a Simple Message Queue in Node.js and RabbitMQ

Messaging Queue enables asynchronous communication, where application puts a message onto a message queue and does not require an immediate response to continuing processing. In this article, we will look at how to build a simple message queue in Node.js and RabbitMQ

The producer and consumer do not interact directly with each other, but they interact with message queue. This way of handling messages decouples the producer from the consumer so that they do not need to interact with the message queue simultaneously.

Initializing Node.js Application

Initialize the application using the following commands:

mkdir node-queue 

cd node-queue

npm init -y

touch index.js

Install the AMQP dependency which will be used for integrating Node.js application with RabbitMQ.

npm install –-save amqplib
Installing RabbitMQ

I have installed RabbitMQ to demonstrate this example by downloading here. Once you have installed, create a queue called ‘node_queue’.

RabbitMQ Implementing Producer

We will now implement a producer in Node.js application, which will put a message on the queue.

const amqp = require('amqplib/callback_api');

amqp.connect('amqp://localhost', function(error, connection) {
  if (error) {
    throw error;
  }
  connection.createChannel(function(error1, channel) {
    if (error1) {
      throw error1;
    }

    let queue = 'node_queue';
    let msg = 'Test message';

    channel.assertQueue(queue, {
      durable: true
    });
    channel.sendToQueue(queue, Buffer.from(msg), {
      persistent: true
    });
    console.log("Sent '%s'", msg);
  });
  setTimeout(function() {
    connection.close();
    process.exit(0)
  }, 500);
});

In the above code snippet, we have imported amqplib. We establish the connection to RabbitMQ server using amqp.connect(). Then we create a channel within which the API for sending message to the queue resides.

channel.assertQueue() asserts a queue into existence. If the queue does not exist, it will create on the server. The message will be sent to the server in byte array format. The connection will be closed after a short period of time.

Now, start the Node.js app by running the command: node index.js.

Navigate to the RabbitMQ dashboard. We will see that one message is ready on the queue.

Shows that one message is available on queue Implementing Consumer

Let us implement a consumer which will consume the message placed on the queue.

amqp.connect('amqp://localhost', function(error0, connection) {
  if (error0) {
    throw error0;
  }
  connection.createChannel(function(error1, channel) {
    if (error1) {
      throw error1;
    }
    var queue = 'node_queue';

    channel.assertQueue(queue, {
      durable: true
    });
    channel.prefetch(1);

    console.log("Waiting for messages in %s", queue);
    channel.consume(queue, function(msg) {

      console.log("Received '%s'", msg.content.toString());

      setTimeout(function() {
        channel.ack(msg);
      }, 1000);
    });
  });
});

Establishing the connection to RabbitMQ server is same as producer. We establish the connection and declare the queue from which we will consume messages.

We also assert queue here as consumer might start before the publisher, therefore we want to ensure that the queue exists before consumer tries to consume messages from it.

channel.consume() retrieves the message from the server.

Restart the application and navigate to the dashboard. We will see that no messages are left to be consumed.

Shows that no message is waiting to be consumed

In this article, I have implemented both producer and consumer in the same application. Note that they can be configured separately depending on the requirement.

The complete example can be found on this GitHub repository.

Top 7 Most Popular Node.js Frameworks You Should Know

Top 7 Most Popular Node.js Frameworks You Should Know

Node.js is an open-source, cross-platform, runtime environment that allows developers to run JavaScript outside of a browser. In this post, you'll see top 7 of the most popular Node frameworks at this point in time (ranked from high to low by GitHub stars).

Node.js is an open-source, cross-platform, runtime environment that allows developers to run JavaScript outside of a browser.

One of the main advantages of Node is that it enables developers to use JavaScript on both the front-end and the back-end of an application. This not only makes the source code of any app cleaner and more consistent, but it significantly speeds up app development too, as developers only need to use one language.

Node is fast, scalable, and easy to get started with. Its default package manager is npm, which means it also sports the largest ecosystem of open-source libraries. Node is used by companies such as NASA, Uber, Netflix, and Walmart.

But Node doesn't come alone. It comes with a plethora of frameworks. A Node framework can be pictured as the external scaffolding that you can build your app in. These frameworks are built on top of Node and extend the technology's functionality, mostly by making apps easier to prototype and develop, while also making them faster and more scalable.

Below are 7of the most popular Node frameworks at this point in time (ranked from high to low by GitHub stars).

Express

With over 43,000 GitHub stars, Express is the most popular Node framework. It brands itself as a fast, unopinionated, and minimalist framework. Express acts as middleware: it helps set up and configure routes to send and receive requests between the front-end and the database of an app.

Express provides lightweight, powerful tools for HTTP servers. It's a great framework for single-page apps, websites, hybrids, or public HTTP APIs. It supports over fourteen different template engines, so developers aren't forced into any specific ORM.

Meteor

Meteor is a full-stack JavaScript platform. It allows developers to build real-time web apps, i.e. apps where code changes are pushed to all browsers and devices in real-time. Additionally, servers send data over the wire, instead of HTML. The client renders the data.

The project has over 41,000 GitHub stars and is built to power large projects. Meteor is used by companies such as Mazda, Honeywell, Qualcomm, and IKEA. It has excellent documentation and a strong community behind it.

Koa

Koa is built by the same team that built Express. It uses ES6 methods that allow developers to work without callbacks. Developers also have more control over error-handling. Koa has no middleware within its core, which means that developers have more control over configuration, but which means that traditional Node middleware (e.g. req, res, next) won't work with Koa.

Koa already has over 26,000 GitHub stars. The Express developers built Koa because they wanted a lighter framework that was more expressive and more robust than Express. You can find out more about the differences between Koa and Express here.

Sails

Sails is a real-time, MVC framework for Node that's built on Express. It supports auto-generated REST APIs and comes with an easy WebSocket integration.

The project has over 20,000 stars on GitHub and is compatible with almost all databases (MySQL, MongoDB, PostgreSQL, Redis). It's also compatible with most front-end technologies (Angular, iOS, Android, React, and even Windows Phone).

Nest

Nest has over 15,000 GitHub stars. It uses progressive JavaScript and is built with TypeScript, which means it comes with strong typing. It combines elements of object-oriented programming, functional programming, and functional reactive programming.

Nest is packaged in such a way it serves as a complete development kit for writing enterprise-level apps. The framework uses Express, but is compatible with a wide range of other libraries.

LoopBack

LoopBack is a framework that allows developers to quickly create REST APIs. It has an easy-to-use CLI wizard and allows developers to create models either on their schema or dynamically. It also has a built-in API explorer.

LoopBack has over 12,000 GitHub stars and is used by companies such as GoDaddy, Symantec, and the Bank of America. It's compatible with many REST services and a wide variety of databases (MongoDB, Oracle, MySQL, PostgreSQL).

Hapi

Similar to Express, hapi serves data by intermediating between server-side and client-side. As such, it's can serve as a substitute for Express. Hapi allows developers to focus on writing reusable app logic in a modular and prescriptive fashion.

The project has over 11,000 GitHub stars. It has built-in support for input validation, caching, authentication, and more. Hapi was originally developed to handle all of Walmart's mobile traffic during Black Friday.

Difference between AngularJS, React, Ember, Backbone, and Node.js.

The most common thing between all of them is that they are Single Page Apps. The SPA is a single page where much of the information remains the same and only some piece of data gets modified when you click on other categories/option.

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