Add: Support for lambda async functions

Add: Support for lambda async functions
Refactor: Update README.md
Refactor: Add async function handler example

Author: Keyur

README.md

@@ -263,6 +263,10 @@ options.maskContent = function(moesifEvent) {
 Type: `Boolean`
 Set to true to print debug logs if you're having integration issues. 
 
+#### __`promisedBased`__
+Type: `Boolean`
+Set to true while using aws lambda async functions. For more details, please refer to - https://docs.aws.amazon.com/lambda/latest/dg/nodejs-handler.html. 
+
 For more documentation regarding what fields and meaning,
 see below or the [Moesif Node API Documentation](https://www.moesif.com/docs/api?javascript).
 

app.js

@@ -49,4 +49,17 @@ exports.handler = function (event, context, callback) {
     });
 };
 
+// Async Functions 
+// Please set promisedBased configuration flag to true while using async functions. For more details, please refer to - https://docs.aws.amazon.com/lambda/latest/dg/nodejs-handler.html.
+
+// moesifOptions.promisedBased = true; 
+
+// exports.handler = async (event, context) => {
+//   const response = {
+//     statusCode: 200,
+//     body: JSON.stringify({ message: 'hello world' })
+//   }
+//   return response
+// }
+
 exports.handler = moesif(moesifOptions, exports.handler);

lib/index.js

@@ -154,15 +154,33 @@ module.exports = function (options, handler) {
   };
 
   var moesifMiddleware = function (event, context, callback) {
-    logMessage(options.debug, 'moesifMiddleware', 'start');
     moesifConfigManager.tryGetConfig();
 
-    var next = function (err, result) {
-      logEvent(event, context, err, result, options, moesifController);
-      callback(err, result)
-    };
+    if (callback && typeof callback === 'function' && !options.promisedBased) {
+      logMessage(options.debug, 'moesifMiddleware', 'start');
+      var next = function (err, result) {
+        logEvent(event, context, err, result, options, moesifController);
+        callback(err, result)
+      };
+
+      return handler(event, context, next);
+    } else {
+      var returnedPromise = handler(event, context, callback);
 
-    handler(event, context, next);
+      if (returnedPromise && returnedPromise.then && typeof returnedPromise.then === 'function') {
+      return returnedPromise.then((result) => {
+        return logEvent(event, context, null, result, options, moesifController).then(() => {
+          return result;
+        });
+      }).catch((err) => {
+        logEvent(event, context, err, {}, options, moesifController);
+        throw err;
+      });
+    } else {
+      logMessage(options.debug, 'moesifMiddleware', 'Can not log promised based handler, please check your configuration.');
+      return returnedPromise;
+    }
+    }
   };
 
   moesifMiddleware.updateUser = function(userModel, cb) {
@@ -303,20 +321,24 @@ function logEvent(event, context, err, result, options, moesifController) {
 
     logMessage(options.debug, 'logEvent', 'sending data invoking moesifAPI');
 
-    moesifController.createEvent(new EventModel(logData), function(err) {
-      if (err) {
-        logMessage(options.debug, 'logEvent', 'Moesif API failed with err=' + JSON.stringify(err));
-        if (options.callback) {
-          options.callback(err, logData);
-        }
-      } else {
-        logMessage(options.debug, 'logEvent', 'Moesif API succeeded');
-        if(options.callback) {
-          options.callback(null, logData);
+    return new Promise((resolve) => {
+      moesifController.createEvent(new EventModel(logData), function(err) {
+        if (err) {
+          logMessage(options.debug, 'logEvent', 'Moesif API failed with err=' + JSON.stringify(err));
+          if (options.callback) {
+            options.callback(err, logData);
+          }
+        } else {
+          logMessage(options.debug, 'logEvent', 'Moesif API succeeded');
+          if(options.callback) {
+            options.callback(null, logData);
+          }
         }
-      }
-    });
+        resolve();
+      });
+    }) 
   }
+  return Promise.resolve();
 }
 
 function bodyToBase64(body) {