Add the updateToken method to reconnect after a token refresh

Author: xowor

README.md

@@ -69,6 +69,12 @@ ArduinoCloud.onPropertyValue(thingId, propertyName, updateCb).then(() => {
   // updateCb(message) will be called every time a new value is available. Value can be string, number, or a boolean depending on the property type
 });
 
+// Re-connect with a new authentication token, keeping the subscriptions
+// to the Things topics
+ArduinoCloud.updateToken(newToken).then(() => {
+  // Successful reconnection with the provided new token
+});
+
 ```
 
 ## Run tests

src/index.js

@@ -49,6 +49,7 @@ import CBOR from 'cbor-js';
 import ArduinoCloudError from './ArduinoCloudError';
 
 let connection = null;
+let connectionOptions = null;
 const subscribedTopics = {};
 const propertyCallback = {};
 const arduinoCloudPort = 8443;
@@ -82,6 +83,8 @@ const connect = options => new Promise((resolve, reject) => {
     onConnected: options.onConnected,
   };
 
+  connectionOptions = opts;
+
   if (connection) {
     return reject(new Error('connection failed: connection already open'));
   }
@@ -222,6 +225,40 @@ const disconnect = () => new Promise((resolve, reject) => {
   return resolve();
 });
 
+const updateToken = token => new Promise((resolve, reject) => {
+  if (!connection) {
+    return reject(new Error('disconnection failed: connection closed'));
+  }
+
+  try {
+    // Disconnect to the connection using the old token
+    connection.disconnect();
+  } catch (error) {
+    // Ignore disconnection errors that comes out when Paho is reconnecting
+  }
+
+  // Remove the connection
+  connection = null;
+
+  return resolve();
+})
+  .then(() => {
+    // Reconnect using the new token
+    const reconnectOptions = Object.assign({}, connectionOptions, { token });
+    return connect(reconnectOptions);
+  })
+  .then(() => {
+    // Re-subscribe to all topics subscribed before the reconnection
+    Object.values(subscribedTopics).forEach((subscribeParams) => {
+      subscribe(subscribeParams.topic, subscribeParams.cb);
+    });
+
+    if (typeof connectionOptions.onConnected === 'function') {
+      // Call the connection callback (with the reconnection param set to true)
+      connectionOptions.onConnected(true);
+    }
+  });
+
 const subscribe = (topic, cb) => new Promise((resolve, reject) => {
   if (!connection) {
     return reject(new Error('subscription failed: connection closed'));
@@ -399,6 +436,7 @@ const onPropertyValue = (thingId, name, cb) => {
 export default {
   connect,
   disconnect,
+  updateToken,
   subscribe,
   unsubscribe,
   sendMessage,