iamqp/src/main/fanout/fanout_producer.js

RabbitMQ wrapper for NodeJS with several produce(reply)/consume scenarios

const MESSAGES = require('../internal').MESSAGES
const _isNull = require('lodash/isNull')

/**
 * Create a producer for an exchange of the fanout type.
 * Multiple fanout producers can fanout to multiple fanout consumers.
 * Init example:
 * <pre>
 *     const iamqp              = require('iamqp');
 *     const amqpUri            = 'amqp://localhost';
 *     const fanoutChannel      = 'fanout-channel-a';
 *     let fanoutProducer       = new iamqp.FanoutProducer(amqpUri, fanoutChannel);
 *
 *     // This needs to be done or the errors will bubble up.
 *     fanoutProducer.getEventer().on('error', (err) => {
 *       console.log('fanout producer error:' + err.message);
 *     });
 *
 *     // For when the connection is established.
 *     fanoutProducer.getEventer().on('connected', () => {
 *       console.log('fanout producer connected');
 *     });
 *
 *     // Open the connection - this takes some time and is not sync
 *     fanoutProducer.openConnection();
 *
 *     // ...
 *
 *     // Fanout a single message.
 *     let isFanout = fanoutProducer.fanout({
 *       'a': 3
 *     });
 *
 *     // ...
 *
 *     // Close the connection
 *     if (fanoutProducer.closeConnection()) {
 *       console.log('fanout producer connection closing ...');
 *     }
 * </pre>
 * ...
 */
class FanoutProducer extends require('../common') {
  /**
   * @param {AmqpURI} amqpUri
   * @param {ChannelName} channelName
   * @param {Configuration} [configuration]
   */
  constructor (amqpUri, channelName, configuration) {
    super(amqpUri, channelName, configuration)
    this._name = `FANOUT-PRODUCER: ${this._configuration.channelName}`
    this._messageDispatcherWrapper('info', MESSAGES.INIT)

    // Comes from the common class where the connection occurs
    this._E.on('connected', () => {
      this._amqp.connection.createChannel((channelCreatingErr, channelCreated) => {
        if (channelCreatingErr) {
          this._emitAndDispatchError(`${MESSAGES.CHANNEL_ERROR} -> ${channelCreatingErr.message}`)
        } else {
          this._messageDispatcherWrapper('info', `${MESSAGES.CHANNEL_READY} -> ${MESSAGES.EXCHANGE_ASSERTING} -> ${MESSAGES.FANOUT}`)
          this._amqp.channel = channelCreated
          this._amqp.channel.assertExchange(this._configuration.channelName, 'fanout', {
            durable: false
          })
        }
      })
    })
  }

  /**
   * Fanout a message.
   * @param {number | string | boolean | Object | Array} contentToPublish
   * @returns {boolean}
   */
  fanout (contentToPublish) {
    const data = this._commonPublishPreparations(contentToPublish)
    if (!_isNull(data)) {
      this._amqp.channel.publish(this._configuration.channelName, '', data)
      return true
    }

    return false
  }
}

module.exports = FanoutProducer