ascoltatori/lib/decorator_ascoltatore.js

The pub/sub library for node backed by Redis, MongoDB, AMQP (RabbitMQ), ZeroMQ, Kafka, MQTT (Mosquitto) or just plain node!

"use strict";

var steed = require("steed")();
var AbstractAscoltatore = require("./abstract_ascoltatore");

/**
 * Decorates totally another ascoltatore, doing nothing
 * but forwarding the method calls, this should
 * be a reference implementation for other decorators.
 *
 * @param {Object} decorated The decorated Ascoltatore
 * @api public
 */
function DecoratorAscoltatore(decorated) {
  this._ascoltatore = decorated;
  AbstractAscoltatore.prototype._setPublish.call(this);
}

/**
 * Translate the topic name in another
 *
 * @param String topic The topic name
 * @param Function next The function that will be called
 * @api public
 */
DecoratorAscoltatore.prototype.wrapTopic = function(topic, next) {
  next(null, topic);
};

/**
 * Translate the callback in another
 *
 * @param Function callback The callback to be translated
 * @param Function next The function that will be called
 * @api public
 */
DecoratorAscoltatore.prototype.wrapCallback = function(callback, next) {
  next(null, callback);
};

/**
 * Translate the payload in another
 *
 * @param String payload The payload
 * @param Function next The function that will be called
 * @api public
 */
DecoratorAscoltatore.prototype.wrapPayload = function(payload, next) {
  next(null, payload);
};

/**
 * Forwarding methods
 *
 * @api private
 */

DecoratorAscoltatore.prototype.on = function(event, callback) {
  this._ascoltatore.on(event, callback);
  return this;
};

DecoratorAscoltatore.prototype.once = function(event, callback) {
  this._ascoltatore.once(event, callback);
  return this;
};

DecoratorAscoltatore.prototype.removeListener = function(event, callback) {
  this._ascoltatore.removeListener(event, callback);
  return this;
};

DecoratorAscoltatore.prototype.subscribe = function(topic, callback, done) {
  var that = this;
  steed.waterfall([

    function(cb) {
      that.wrapTopic(topic, cb);
    },

    function(newTopic, cb) {
      that.wrapCallback(callback, function(err, newCallback) {
        cb(err, newTopic, newCallback);
      });
    },

    function(newTopic, newCallback, cb) {
      that._ascoltatore.subscribe(newTopic, newCallback, cb);
    }
  ], done);
};

DecoratorAscoltatore.prototype.unsubscribe = function(topic, callback, done) {
  var that = this;
  steed.waterfall([

    function(cb) {
      that.wrapTopic(topic, cb);
    },

    function(newTopic, cb) {
      that.wrapCallback(callback, function(err, newCallback) {
        cb(err, newTopic, newCallback);
      });
    },

    function(newTopic, newCallback, cb) {
      that._ascoltatore.unsubscribe(newTopic, newCallback, cb);
    }
  ], done);
};

DecoratorAscoltatore.prototype.publish = function(topic, payload, options, done) {
  var that = this;
  steed.waterfall([

    function(cb) {
      that.wrapTopic(topic, cb);
    },

    function(newTopic, cb) {
      that.wrapPayload(payload, function(err, newPayload) {
        cb(err, newTopic, newPayload);
      });
    },

    function(newTopic, newPayload, cb) {
      that._ascoltatore.publish(newTopic, newPayload, options, cb);
    }
  ], done);
};

DecoratorAscoltatore.prototype.close = function(done) {
  this._ascoltatore.close(done);
};

DecoratorAscoltatore.prototype.unsub = function(topic, callback, done) {
  this.unsubscribe(topic, callback, done);
};

DecoratorAscoltatore.prototype.sub = function(topic, callback, done) {
  this.subscribe(topic, callback, done);
};

DecoratorAscoltatore.prototype.pub = function(topic, payload, options, done) {
  this.publish(topic, payload, options, done);
};

module.exports = DecoratorAscoltatore;