From 5d2fc21fab7ea1e79a543dd72201e1afa975c442 Mon Sep 17 00:00:00 2001
From: Loren West <github@lorenwest.com>
Date: Thu, 25 Dec 2014 22:08:04 -0800
Subject: [PATCH] Support asynchronous commands

---
 lib/api/routes.js | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/lib/api/routes.js b/lib/api/routes.js
index f2bdc31..864a2b5 100644
--- a/lib/api/routes.js
+++ b/lib/api/routes.js
@@ -60,9 +60,8 @@ router.get("/commands", function(req, res) {
 });
 
 router.post("/commands/:command", function(req, res) {
-  var command = req.params.command;
-  var result = Cylon.commands[command].apply(Cylon, req.commandParams);
-  res.json({ result: result });
+  var command = Cylon.commands[req.params.command];
+  router.runCommand(req, res, Cylon, command);
 });
 
 router.get("/robots", function(req, res) {
@@ -79,8 +78,7 @@ router.get("/robots/:robot/commands", load, function(req, res) {
 
 router.all("/robots/:robot/commands/:command", load, function(req, res) {
   var command = req.robot.commands[req.params.command];
-  var result = command.apply(req.robot, req.commandParams);
-  res.json({ result: result });
+  router.runCommand(req, res, req.robot, command);
 });
 
 router.get("/robots/:robot/devices", load, function(req, res) {
@@ -117,8 +115,7 @@ router.get("/robots/:robot/devices/:device/commands", load, function(req, res) {
 
 router.all("/robots/:robot/devices/:device/commands/:command", load, function(req, res) {
   var command = req.device.commands[req.params.command];
-  var result = command.apply(req.device, req.commandParams);
-  res.json({ result: result });
+  router.runCommand(req, res, req.device, command);
 });
 
 router.get("/robots/:robot/connections", load, function(req, res) {
@@ -128,3 +125,17 @@ router.get("/robots/:robot/connections", load, function(req, res) {
 router.get("/robots/:robot/connections/:connection", load, function(req, res) {
   res.json({ connection: req.connection });
 });
+
+// Run an MCP, Robot, or Device command.  Process the results immediately,
+// or asynchronously if the result is a Promise.
+router.runCommand = function(req, res, my, command) {
+  var result = command.apply(my, req.commandParams);
+  if (typeof result.then === 'function') {
+    result
+      .then(function(result) {return res.json({result: result})})
+      .catch(function(err) {return res.status(500).json({error: err})});
+  }
+  else {
+    res.json({ result: result });
+  }
+};