iamqp

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server. Init example: * <pre> * const iamqp = require('iamqp'); * const amqpUri = 'amqp://localhost'; * const rpcChannel = 'rpc-channel-a'; * let rpcServer = new iamqp.RPCServer(amqpUri, rpcChannel); * * // This needs to be done or the errors will bubble up. * rpcServer.getEventer().on('error', (err) => { * console.log('RPC server error:' + err.message); * }); * * // For when the connection is established. * rpcServer.getEventer().on('connected', () => { * console.log('RPC server connected'); * }); * * // An event gets emitted on each call. * // Handling of the pCorrelationId is optional and should be done only if you expect a single RPC server instance * // to handle multiple RPC clients. * // For example if the RPC server interacts with a DB on the behalf of the client and the calls are just * // coming in. * // This means that you can parameters pCorrelationId in both receiving the call and responding. * rpcServer.getEventer().on('call', (callData, pCorrelationId) => { * console.log('RPC server got a call: ' + callData); * * // ... * * let isServerResponding = rpcServer.respond({ * 'a': 3 * }, pCorrelationId); * }); * * // Open the connection - this takes some time and is not sync * rpcServer.openConnection(); * * // ... * * // Close the connection * if (rpcServer.closeConnection()) { * console.log('RPC server connection closing ...'); * } * </pre> * ... */ class RpcServer extends require('../common') { /** * @param {AmqpURI} amqpUri * @param {ChannelName} channelName * @param {Configuration} [configuration] */ constructor (amqpUri, channelName, configuration) { super(amqpUri, channelName, configuration) this._name = `RPC-SERVER: ${this._configuration.channelName}` this._messageDispatcherWrapper('info', MESSAGES.INIT) this._lastMessage = null this._calls = {} this._E.on('connected', () => { this._createChannel() }) } /** * Create the channel. * @private */ _createChannel () { this._amqp.connection.createChannel((channelCreatingErr, createdChannel) => { if (channelCreatingErr) { this._emitAndDispatchError(`${MESSAGES.CHANNEL_ERROR} -> ${channelCreatingErr.message}`) return } this._messageDispatcherWrapper('info', `${MESSAGES.CHANNEL_READY} -> ${MESSAGES.QUEUE_ASSERTING} -> ${MESSAGES.BINDING_CONSUMER_FUNCTION}`) this._lastMessage = null this._amqp.channel = createdChannel this._amqp.channel.assertQueue(this._configuration.channelName, { durable: false, arguments: _get(this._configuration, 'configuration.queueArguments', {}) }) // this._amqp.channel.prefetch(1); this._amqp.channel.consume(this._configuration.channelName, (data) => { if ( data && _get(data, 'properties.replyTo', null) && _get(data, 'properties.correlationId', null) ) { this._calls[data.properties.correlationId] = data this._lastMessage = data this._E.emit('call', this._parseConsumedMessage(data), data.properties.correlationId) } else { this._lastMessage = null this._messageDispatcherWrapper('error', `${MESSAGES.GOT_MESSAGE} -> ${MESSAGES.INVALID_PROPERTY}`) } }, { noAck: false }) }) } /** * Respond to the last call/message. * @param {number | string | boolean | Object | Array} contentToPublish * @param {string} correlationId correlation ID (as gotten from the call) parameter to use when the server * is to process multiple calls at once * @returns {boolean} */ respond (contentToPublish, correlationId) { if (this._isReady === true) { let lastMessage = null let isFromCallsStorage = false if (correlationId) { if ( _isString(correlationId) && Object.prototype.hasOwnProperty.call(this._calls, correlationId) ) { lastMessage = this._calls[correlationId] isFromCallsStorage = true } else { this._messageDispatcherWrapper('error', 'attempting to respond with an invalid correlation ID') return false } } else if (this._lastMessage) { lastMessage = this._lastMessage } if ( !lastMessage || !_get(lastMessage, 'properties.replyTo', null) || !_get(lastMessage, 'properties.correlationId', null) ) { this._messageDispatcherWrapper('error', 'attempting to respond to an invalid message') return false } this._amqp.channel.sendToQueue( lastMessage.properties.replyTo, this._preparePublishingMessage(contentToPublish), { correlationId: lastMessage.properties.correlationId } ) this._amqp.channel.ack(lastMessage) process.nextTick(() => { delete this._calls[lastMessage.properties.correlationId] if (!isFromCallsStorage) { this._lastMessage = null } }) return true } else { this._messageDispatcherWrapper('error', `${MESSAGES.RESPOND} -> ${MESSAGES.CONNECTION_ERROR}`) return false } } } module.exports = RpcServer </code></pre> </article> </section> </div> <br class="clear"> <footer> Generated by <a href="https://github.com/jsdoc3/jsdoc">JSDoc 3.6.2</a> on Sun Aug 04 2019 22:10:47 GMT+0200 (Central European Summer Time) using the Minami theme. </footer> <script>prettyPrint();</script> <script src="scripts/linenumber.js"></script> </body> </html>