From 24fd6adee1d8c461d0076396a4728c7841380454 Mon Sep 17 00:00:00 2001
From: Adam Brady <adam@boxxen.org>
Date: Sun, 24 Jan 2016 00:55:06 +1100
Subject: [PATCH] Start using promises internally for service methods

---
 package.json        |  1 +
 src/service.js      | 31 ++++++++++++++++++++++---------
 test-src/service.js | 23 +++++++++++++++++++++--
 3 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/package.json b/package.json
index 3aea77c..5aaa3c0 100644
--- a/package.json
+++ b/package.json
@@ -42,6 +42,7 @@
   "homepage": "https://github.com/hudson-taylor/hudson-taylor",
   "dependencies": {
     "async": "~1.4.0",
+    "bluebird": "^3.1.1",
     "body-parser": "~1.14.1",
     "express": "~4.13.2",
     "ht-schema": "~3.1.4"
diff --git a/src/service.js b/src/service.js
index 02d651a..a9bffc7 100644
--- a/src/service.js
+++ b/src/service.js
@@ -1,8 +1,9 @@
 
 "use strict";
 
-const async   = require("async");
-const s       = require("ht-schema");
+const async    = require("async");
+const s        = require("ht-schema");
+const bluebird = require("bluebird");
 
 const utils = require("./utils");
 
@@ -59,11 +60,7 @@ let Service = function Service(Transports, config) {
             let _tmp = this._methods[context.method];
             if(!_tmp) return cb({ error: "unknown-method", method: context.method });
 
-            let finish = (err, response) => {
-
-                if(err) {
-                    return cb(err);
-                }
+            let finish = (response) => {
 
                 let _afterMiddleware = this._middleware.after.filter((m) => {
                     if(m.method && m.method !== context.method) return false;
@@ -95,12 +92,28 @@ let Service = function Service(Transports, config) {
                             error: err.message
                         });
                     }
-                    return _tmp.fn(data, finish);
+                    return go();
                 });
             } else {
-                _tmp.fn(data, finish);
+                go();
             }
 
+            function go() {
+
+                // Handle both callbacks and promises here.
+                let callbackHandler = function(err, response) {
+                    if(err) return cb(err);
+                    return finish(response);
+                }
+
+                let response = _tmp.fn(data, callbackHandler);
+
+                if(response && typeof response.then === 'function') {
+                    callbackHandler = null;
+                    return response.then(finish).catch(cb);
+                }
+
+            }
 
         });
 
diff --git a/test-src/service.js b/test-src/service.js
index 55ceda2..a64a8d8 100644
--- a/test-src/service.js
+++ b/test-src/service.js
@@ -1,8 +1,9 @@
 
 "use strict";
 
-const assert = require('assert');
-const s      = require('ht-schema');
+const assert   = require('assert');
+const s        = require('ht-schema');
+const bluebird = require('bluebird');
 
 const Service = require('../lib/service');
 
@@ -123,6 +124,24 @@ describe("Service", function() {
 
     });
 
+    it("should allow returning promise from function", function(done) {
+
+      let service = new Service();
+
+      service.on("test", function() {
+        return new bluebird.Promise(function(resolve, reject) {
+          return resolve(_data);
+        });
+      });
+
+      service.call("test", null, function(err, response) {
+        assert.ifError(err);
+        assert.deepEqual(response, _data);
+        done();
+      });
+
+    });
+
   });
 
   describe("listen", function() {