Send binary Brackets-Node command responses

appshell/node-core/ConnectionManager.js

@@ -82,6 +82,18 @@ maxerr: 50, node: true */
             }
         }
     };
+
+    /**
+     * @private
+     * Sends a binary message over the WebSocket. Implicitly interpreted as a
+     * message of type "commandResponse".
+     * @param {Buffer} message
+     */
+    Connection.prototype._sendBinary = function (message) {
+        if (this._ws && this._connected) {
+            this._ws.send(message, {binary: true, mask: false});
+        }
+    };
 
     /**
      * @private
@@ -138,15 +150,29 @@ maxerr: 50, node: true */
      * Sends a response to a command execution
      * @param {number} id unique ID of the command that was executed. ID is
      *    generated by the client when the command is issued.
-     * @param {object} response Result of the command execution. Must be
-     *    JSON.stringify-able.
+     * @param {object|Buffer} response Result of the command execution. Must
+     *    either be JSON.stringify-able or a raw Buffer. In the latter case,
+     *    the result will be sent as a binary response.
      */
     Connection.prototype.sendCommandResponse = function (id, response) {
-        this._send("commandResponse", {id: id, response: response });
+        if (Buffer.isBuffer(response)) {
+            // Assume the id is an unsigned 32-bit integer, which is encoded
+            // as a four-byte header
+            var header = new Buffer(4);
+
+            header.writeUInt32LE(id, 0);
+
+            // Prepend the header to the message
+            var message = Buffer.concat([header, response], response.length + 4);
+
+            this._sendBinary(message);
+        } else {
+            this._send("commandResponse", {id: id, response: response });
+        }
     };
 
     /**
-     * Sends a response indicating that an errur occurred during command 
+     * Sends a response indicating that an error occurred during command 
      * execution
      * @param {number} id unique ID of the command that was executed. ID is
      *    generated by the client when the command is issued.