NRP (Node Redis Pubsub)

This library is now mainly maintained by @rangermauve and @narcisoguillen

Simple pubsub for node using Redis. Why use NRP instead of Node's EventEmitter? It is useful when your Node application needs to share data with other applications. In that case EventEmitter will not help you, you need an external pubsub provider. Redis is pretty good at this, but its pubsub API is strange. So you use this wrapper.

Install and test

$ npm install node-redis-pubsub      # Install locally
$ npm install -g node-redis-pubsub   # Install globally
$
$ make test   # test (devDependencies need to be installed and a Redis server up)

Usage

Setup

for a trusted environment where Redis runs locally, unprotected on a port blocked by firewall.

var NRP    = require('node-redis-pubsub');
var config = {
  port  : 6379  , // Port of your locally running Redis server
  scope : 'demo'  // Use a scope to prevent two NRPs from sharing messages
};

var nrp = new NRP(config); // This is the NRP client

for a remote Redis server

var NRP = require('node-redis-pubsub');

var config = {
  port: 1234                        , // Port of your remote Redis server
  host: 'path.to.remote.redis.host' , // Redis server host, defaults to 127.0.0.1
  auth: 'password'                  , // Password
  scope: 'demo'                       // Use a scope to prevent two NRPs from sharing messages
};

var nrp = new NRP(config); // This is the NRP client

heroku and other services provide you with an environment variable REDIS_URL

var NRP = require('node-redis-pubsub');
var url = process.env.REDIS_URL;

var config = {
    url: url
};

var nrp = new NRP(config); // This is the NRP client

reuse existing redis pub and sub connections

var NRP = require('node-redis-pubsub');

var redisPub = redis.createClient();
var redisSub = redis.createClient();

var config = {
  emitter: redisPub,                      // Pass in an existing redis connection that should be used for pub
  receiver: redisSub,                     // Pass in an existing redis connection that should be used for sub
}

var nrp = new NRP(config); // This is the NRP client

Simple pubsub

nrp.on('say hello', function(data){
  console.log('Hello ' + data.name);
});

nrp.emit('say hello', { name: 'Louis' });   // Outputs 'Hello Louis'

// You can use patterns to capture all messages of a certain type
// The matched channel is given as a second parameter to the callback
nrp.on('city:*', (data, channel) => {
  console.log(data.city + ' is great');
});

nrp.emit('city:hello' , { city: 'Paris' });         // Outputs 'Paris is great'
nrp.emit('city:yeah'  , { city: 'San Francisco' }); // Outputs 'San Francisco is great'

Do something after subscribe finishes

nrp.on('mydata:sync', function(myData) {
  console.log(myData);
}, function() {
  nrp.emit('mydata:requestsync'); // request a sync of the data after the handler is registered, so there are no race conditions
});

Unsubscribe

var unsubscribe = nrp.on('say hello', function(data){
  // Never called
});

unsubscribe([Callback]);

Shut down connections

// Safely (connections will be closed properly once all commands are sent)
nrp.quit();

// Dangerously (connections will be immediately terminated)
nrp.end();

Listen for errors

nrp.on("error", function(){
  // Handle errors here
});

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

louischatriot/node-redis-pubsub