feat(push): initial fcm transport implementation

.env.example

@@ -51,3 +51,9 @@ SMTP_PASSWORD=
 SMTP_SECURE=
 SMTP_FROM=
 SMTP_TEST_RECEIVER=
+
+
+# GOOGLE FCM(GCM) TRANSPORT
+PUSH_FCM_API_KEY=
+PUSH_FCM_DEFAULT_SENDER_ID=
+PUSH_FCM_TEST_REGISTRATION_TOKEN=

lib/transports/push.fcm.js

@@ -0,0 +1,232 @@
+'use strict';
+
+
+/**
+ * @name push
+ * @module push
+ * @description fcm(gcm) push notification transport
+ * @see {@link https://github.com/ToothlessGear/node-gcm}
+ * @license MIT
+ * @author lally elias <lallyelias87@gmail.com>
+ * @since 0.1.0
+ * @version 0.1.0
+ * @public
+ */
+
+
+/* dependencies */
+const _ = require('lodash');
+const { getString } = require('@lykmapipo/env');
+const gcm = require('node-gcm');
+
+
+/**
+ * @name defaults
+ * @description default configuration options
+ * @type {Object}
+ * @author lally elias <lallyelias87@gmail.com>
+ * @since 0.1.0
+ * @version 0.1.0
+ * @private
+ */
+exports.defaults = {
+  //Google FCM API Key
+  apiKey: getString('PUSH_FCM_API_KEY'),
+};
+
+
+/**
+ * @name countryCode
+ * @description transport country code
+ * @type {String}
+ * @author lally elias <lallyelias87@gmail.com>
+ * @since 0.1.0
+ * @version 0.1.0
+ * @public
+ */
+exports.countryCode = undefined;
+
+
+/**
+ * @name countryName
+ * @description transport country name
+ * @type {String}
+ * @author lally elias <lallyelias87@gmail.com>
+ * @since 0.1.0
+ * @version 0.1.0
+ * @public
+ */
+exports.countryCode = undefined;
+
+
+/**
+ * @name name
+ * @description name of the transport
+ * @type {String}
+ * @author lally elias <lallyelias87@gmail.com>
+ * @since 0.1.0
+ * @version 0.1.0
+ * @public
+ */
+exports.name = 'fcm-push';
+
+
+/**
+ * @name toObject
+ * @function toObject
+ * @description convert transport details into object
+ * @author lally elias <lallyelias87@gmail.com>
+ * @since 0.1.0
+ * @version 0.1.0
+ * @public
+ */
+exports.toObject = function toObject() {
+  const object = {
+    name: exports.name,
+    countryCode: exports.countryCode,
+    countryName: exports.countryName
+  };
+  return object;
+};
+
+
+/**
+ * @name init
+ * @function init
+ * @description initialize transport
+ * @author lally elias <lallyelias87@gmail.com>
+ * @since 0.1.0
+ * @version 0.1.0
+ * @private
+ */
+exports.init = function (options) {
+
+  //initialize transport if not exist
+  if (!exports.transport) {
+
+    //merge options
+    exports.options =
+      _.merge({}, exports.defaults, exports.options, options);
+
+    //ensure Google FCM API Key
+    const { apiKey } = exports.options;
+
+    //create transport
+    //initiate node GCM(FCM) sender
+    //@see {@link https://github.com/ToothlessGear/node-gcm#example-application}
+    exports.transport = new gcm.Sender(apiKey);
+
+  }
+
+};
+
+
+/**
+ * @name _send
+ * @function _send
+ * @description send push notification message using fcm(gcm) transport
+ * 
+ * Note!: message options may contain push message data & notification
+ * 
+ * @param {Message} message valid message instance
+ * @param {Function} done a callback to invoke on success or failure
+ * @author lally elias <lallyelias87@gmail.com>
+ * @since 0.1.0
+ * @version 0.1.0
+ * @private
+ */
+exports._send = function (message, done) {
+
+  //ensure transport is initialized
+  exports.init();
+
+  //prepare FCM push notification compliant payload
+  let payload =
+    _.merge({}, message.options, {
+      notification: {
+        title: message.subject,
+        body: message.body
+      }
+    });
+
+  //prepare push notification recipients
+  const to = message.to && message.to.length > 1 ? message.to : message.to[0];
+
+  //instantiate node-gcm message
+  payload = new gcm.Message(payload);
+
+  //perform actual send
+  exports.transport.send(payload, to, function (error, response) {
+
+    //check for reachability
+    //@see {@link https://github.com/ToothlessGear/node-gcm/blob/master/lib/sender.js#L153}
+    if (error && _.isNumber(error) && error >= 500) {
+      error = new Error('GCM(FCM) Server Unavailable');
+      error.status = 'Internal Server Error';
+      error.code = error;
+    }
+
+    //check for authorization
+    //@see {@link https://github.com/ToothlessGear/node-gcm/blob/master/lib/sender.js#L157}
+    if (error && _.isNumber(error) && error === 401) {
+      error = new Error(
+        'Unauthorized (401). Check that your API token is correct.'
+      );
+      error.status = 'Unauthorized';
+      error.code = error;
+    }
+
+    //check failure response
+    //@see {@link https://github.com/ToothlessGear/node-gcm/blob/master/lib/sender.js#L161}
+    if (error && _.isNumber(error) &&
+      error !== 200 && error !== 401 && error <= 500) {
+      error = new Error('Invalid Request');
+      error.status = 'Invalid Request';
+      error.code = error;
+    }
+
+    //respond with error
+    if (error) {
+      done(error);
+    }
+
+    //respond with success result
+    else {
+      //merge default response details
+      response = _.merge({}, { success: true }, response);
+
+      //process push results if available
+      if (response.results) {
+        response.results = _.map(message.to, function (val, index) {
+          return _.merge({}, { to: val }, response.results[index]);
+        });
+      }
+      done(null, response);
+    }
+
+  });
+
+};
+
+
+/**
+ * @name send
+ * @function send
+ * @description send push notification via transaport
+ * @param {Message} message valid message instance
+ * @param {Function} done callback to invoke on success or failure
+ * @return {Object|Error} send result or error
+ * @since 0.1.0
+ * @version 0.1.0
+ * @public
+ */
+exports.send = function (message, done) {
+
+  //ensure email sender
+  message.sender =
+    (message.sender || getString('PUSH_FCM_SENDER_ID', exports.name));
+
+  //perform actual push notification sending
+  exports._send(message, done);
+
+};