Introduction to Node Redis PubSub

Node-Redis-PubSub is a powerful library that allows developers to implement pub/sub (publish/subscribe) messaging systems on top of Redis, a popular in-memory data structure store. This guide introduces the key concepts and provides comprehensive examples to help you get started with Node-Redis-PubSub.

Setting Up Node-Redis-PubSub

  const NRP = require('node-redis-pubsub');
  const config = {
    port: 6379,
    host: '127.0.0.1',
    scope: 'demo',
  };
  const nrp = new NRP(config);

Publishing Messages

  nrp.emit('event:message', { text: 'Hello, World!' });

Subscribing to Messages

  nrp.on('event:message', (data) => {
    console.log(`Received data: ${JSON.stringify(data)}`);
  });

Unsubscribing from Events

  const callback = (data) => { console.log(data); };
  nrp.on('event:unsubscribe', callback);
  nrp.off('event:unsubscribe', callback);

Error Handling

  nrp.on('error', (err) => {
    console.error('Redis PubSub error: ', err);
  });

Using Wildcards with Events

  nrp.on('event:*', (data, channel) => {
    console.log(`Received data: ${JSON.stringify(data)} on channel: ${channel}`);
  });

Comprehensive App Example

App Initialization

  const NRP = require('node-redis-pubsub');
  const config = {
    port: 6379,
    host: '127.0.0.1',
    scope: 'myApp',
  };
  const nrp = new NRP(config);

Publish Message

  setInterval(() => {
    nrp.emit('app:heartbeat', { time: Date.now() });
  }, 1000);

Subscribe to Events

  nrp.on('app:heartbeat', (data) => {
    console.log(`Heartbeat at ${new Date(data.time)}`);
  });
  
  nrp.on('app:error', (err) => {
    console.error(`App error: ${err}`);
  });

With Node-Redis-PubSub, you can easily build a variety of real-time applications such as chat apps, live notifications, or IoT data processing systems.

Explore the official documentation for more detailed usage and advanced features.

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