Use json-rpc.

packages/xo-lib/index.js

@@ -4,7 +4,11 @@
 
 var assign = require('lodash.assign');
 var Bluebird = require('bluebird');
+var EventEmitter = require('events').EventEmitter;
 var forEach = require('lodash.foreach');
+var inherits = require('util').inherits;
+var jsonRpc = require('json-rpc');
+var MethodNotFound = require('json-rpc/errors').MethodNotFound;
 var parseUrl = require('url').parse;
 var WebSocket = require('ws');
 
@@ -24,10 +28,6 @@ function makeDeferred() {
   };
 }
 
-function notConnected() {
-  throw new Error('not connected');
-}
-
 function startsWith(string, target) {
   return (string.lastIndexOf(target, 0) === 0);
 }
@@ -52,23 +52,35 @@ function fixUrl(url) {
 //====================================================================
 
 function Xo(url) {
+  // Super constructor.
+  EventEmitter.call(this);
+
+  // Fix the URL (ensure correct protocol and /api/ path).
   this._url = fixUrl(url);
 
-  // Identifier of the next request.
-  this._nextId = 0;
-
-  // Promises linked to the requests.
-  this._deferreds = {};
-
-  // Current WebSocket.
-  this._socket = null;
-
   // Current status which may be:
   // - disconnected
   // - connecting
   // - connected
   this.status = 'disconnected';
+
+  // Will contains the WebSocket.
+  this._socket = null;
+
+  // The JSON-RPC server.
+  var this_ = this;
+  this._jsonRpc = jsonRpc.createServer(function (message) {
+    if (message.type === 'notification') {
+      this_.emit('notification', message);
+    } else {
+      // This object does not support requests.
+      throw new MethodNotFound(message.method);
+    }
+  }).on('data', function (message) {
+    this_._socket.send(JSON.stringify(message));
+  });
 }
+inherits(Xo, EventEmitter);
 
 assign(Xo.prototype, {
   close: function () {
@@ -78,7 +90,7 @@ assign(Xo.prototype, {
   },
 
   connect: Bluebird.method(function () {
-    if (this.status === 'connected') {
+    if (this._socket) {
       return;
     }
     this.status = 'connecting';
@@ -92,59 +104,27 @@ assign(Xo.prototype, {
     }
     var socket = this._socket = new WebSocket(this._url, '', opts);
 
+    // Used to avoid binding listeners to this object.
+    var this_ = this;
+
     // When the socket opens, send any queued requests.
     socket.addEventListener('open', function () {
       this.status = 'connected';
 
-      // (Re)Opens accesses.
-      delete this.send;
-
       // Resolves the promise.
       deferred.resolve();
-    }.bind(this));
+    });
 
-    socket.addEventListener('message', function (data) {
-      // `ws` API is lightly different from standard API.
-      if (data.data) {
-        data = data.data;
-      }
-
-      // TODO: Wraps in a promise to prevent releasing the Zalgo.
-      var response = JSON.parse(data);
-
-      var id = response.id;
-
-      var deferred = this._deferreds[id];
-      if (!deferred) {
-        // Response already handled.
-        return;
-      }
-      delete this._deferreds[id];
-
-      if ('error' in response) {
-        return deferred.reject(response.error);
-      }
-
-      if ('result' in response) {
-        return deferred.resolve(response.result);
-      }
-
-      deferred.reject({
-        message: 'invalid response received',
-        object: response,
-      });
-    }.bind(this));
+    socket.addEventListener('message', function (message) {
+      this_._jsonRpc.write(message.data);
+    });
 
     socket.addEventListener('close', function () {
-      // Closes accesses.
-      this.send = notConnected;
+      this_.status = 'disconnected';
+      this_._socket = null;
 
-      // Fails all waiting requests.
-      forEach(this._deferreds, function (deferred) {
-        deferred.reject('not connected');
-      });
-      this._deferreds = {};
-    }.bind(this));
+      this_._jsonRpc.failPendingRequests('connection lost');
+    });
 
     socket.addEventListener('error', function (error) {
       // Fails the connect promise if possible.
@@ -155,22 +135,11 @@ assign(Xo.prototype, {
   }),
 
   call: function (method, params) {
+    var jsonRpc = this._jsonRpc;
+
     return this.connect().then(function () {
-      var socket = this._socket;
-
-      var id = this._nextId++;
-
-      socket.send(JSON.stringify({
-        jsonrpc: '2.0',
-        id: id,
-        method: method,
-        params: params || [],
-      }));
-
-      var deferred = this._deferreds[id] = makeDeferred();
-
-      return deferred.promise;
-    }.bind(this));
+      return jsonRpc.request(method, params);
+    });
   },
 });
 

packages/xo-lib/package.json

@@ -26,6 +26,7 @@
   ],
   "dependencies": {
     "bluebird": "^2.9.6",
+    "json-rpc": "git://github.com/julien-f/js-json-rpc",
     "lodash.assign": "^3.0.0",
     "lodash.foreach": "^3.0.1",
     "ws": "^0.7.1"