Fix issues with replying to RPC messages using Promises (#44)

* Fix issues with replying to RPC messages using Promises

Issue 1: If a message is received with the replyTo field set (an RPC
message) and the onMessage function that's passed to activateConsumer()
or startConsumer() returns a Promise and the Promise isn't an ES6
Promise, a JSON version of the Promise itself may be returned in the
reply message instead of the Promise's resolved value.
https://stackoverflow.com/questions/27746304/how-do-i-tell-if-an-object-is-a-promise

Issue 2: If a message is received with the replyTo field set (an RPC
message) and the onMessage function that's passed to startConsumer()
returns a Promise, the Promise's resolved value isn't returned in the
reply message. Instead a JSON version of the entire Promise is returned.

* Rebuild transpiled library from Typescript source

Update version information in package file to match latest released version

* Allow the onMessage callback that's passed to activateConsumer() and
startConsumer() to return a promise regardless of whether or not the
replyTo field is set.

startConsumer() can automatically ack the message. If noAck == false and
manualAck == false and onMessage returns a promise, wait until the
promise is resolved before acknowledging the message.

* Rebuild transpiled library from Typescript source

Author: austin-beer

lib/amqp-ts.d.ts

@@ -5,6 +5,7 @@
  * methods and properties starting with '_' signify that the scope of the item should be limited to
  * the inside of the enclosing namespace.
  */
+/// <reference types="node" />
 import * as AmqpLib from "amqplib/callback_api";
 import * as Promise from "bluebird";
 import * as winston from "winston";
@@ -31,8 +32,8 @@ export declare class Connection extends EventEmitter {
         [id: string]: Binding;
     };
     constructor(url?: string, socketOptions?: any, reconnectStrategy?: Connection.ReconnectStrategy);
-    private rebuildConnection();
-    private tryToConnect(thisConnection, retry, callback);
+    private rebuildConnection;
+    private tryToConnect;
     _rebuildAll(err: Error): Promise<void>;
     close(): Promise<void>;
     /**
@@ -48,7 +49,7 @@ export declare class Connection extends EventEmitter {
     declareExchange(name: string, type?: string, options?: Exchange.DeclarationOptions): Exchange;
     declareQueue(name: string, options?: Queue.DeclarationOptions): Queue;
     declareTopology(topology: Connection.Topology): Promise<any>;
-    getConnection: AmqpLib.Connection;
+    readonly getConnection: AmqpLib.Connection;
 }
 export declare namespace Connection {
     interface ReconnectStrategy {
@@ -99,8 +100,8 @@ export declare class Exchange {
     _options: Exchange.DeclarationOptions;
     _deleting: Promise<void>;
     _closing: Promise<void>;
-    name: string;
-    type: string;
+    readonly name: string;
+    readonly type: string;
     constructor(connection: Connection, name: string, type?: string, options?: Exchange.DeclarationOptions);
     _initialize(): void;
     /**
@@ -149,7 +150,7 @@ export declare class Queue {
     _consumerStopping: boolean;
     _deleting: Promise<Queue.DeleteResult>;
     _closing: Promise<void>;
-    name: string;
+    readonly name: string;
     constructor(connection: Connection, name: string, options?: Queue.DeclarationOptions);
     _initialize(): void;
     static _packMessageContent(content: any, options: any): Buffer;

lib/amqp-ts.js

@@ -941,23 +941,21 @@ export class Queue {
         }
         var payload = Queue._unpackMessageContent(msg);
         var result = this._consumer(payload);
-        if (!(result instanceof Promise)) {
-          result = Promise.resolve(result);
-        }
-        result.then((resultValue) => {
-        // check if there is a reply-to
-        if (msg.properties.replyTo) {
-          var options: any = {};
-          resultValue = Queue._packMessageContent(resultValue, options);
-          this._channel.sendToQueue(msg.properties.replyTo, resultValue, options);
-        }
-
+        // convert the result to a promise if it isn't one already
+        Promise.resolve(result).then((resultValue) => {
+          // check if there is a reply-to
+          if (msg.properties.replyTo) {
+            var options: any = {};
+            resultValue = Queue._packMessageContent(resultValue, options);
+            this._channel.sendToQueue(msg.properties.replyTo, resultValue, options);
+          }
           // 'hack' added to allow better manual ack control by client (less elegant, but should work)
-        if (this._consumerOptions.manualAck !== true && this._consumerOptions.noAck !== true) {
+          if (this._consumerOptions.manualAck !== true && this._consumerOptions.noAck !== true) {
             this._channel.ack(msg);
-          }}).catch((err) => {
-              log.log("error", "Queue.onMessage RPC promise returned error: " + err.message, { module: "amqp-ts" });
-            });
+          }
+        }).catch((err) => {
+          log.log("error", "Queue.onMessage RPC promise returned error: " + err.message, { module: "amqp-ts" });
+        });
       } catch (err) {
         /* istanbul ignore next */
         log.log("error", "Queue.onMessage consumer function returned error: " + err.message, { module: "amqp-ts" });
@@ -980,11 +978,9 @@ export class Queue {
         message._message = msg;
         message._channel = this._channel;
         var result = this._consumer(message);
-        if (!(result instanceof Promise)) {
-          result = Promise.resolve(result);
-        }
-        result.then((resultValue) => {
-        // check if there is a reply-to
+        // convert the result to a promise if it isn't one already
+        Promise.resolve(result).then((resultValue) => {
+          // check if there is a reply-to
           if (msg.properties.replyTo) {
             if (!(resultValue instanceof Message)) {
               resultValue = new Message(resultValue, {});
@@ -993,8 +989,8 @@ export class Queue {
             this._channel.sendToQueue(msg.properties.replyTo, resultValue.content, resultValue.properties);
           }
         }).catch((err) => {
-              log.log("error", "Queue.onMessage RPC promise returned error: " + err.message, { module: "amqp-ts" });
-            });
+          log.log("error", "Queue.onMessage RPC promise returned error: " + err.message, { module: "amqp-ts" });
+        });
       } catch (err) {
         /* istanbul ignore next */
         log.log("error", "Queue.onMessage consumer function returned error: " + err.message, { module: "amqp-ts" });