TCP connections to ROS bridge for node

Gruntfile.js

@@ -35,6 +35,9 @@ module.exports = function(grunt) {
       },
       examples: {
         src: ['./test/examples/*.js']
+      },
+      tcp: {
+        src: ['./test/tcp/*.js']
       }
     },
     uglify: {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "roslibjs",
-  "main": "./src/RosLib.js",
+  "main": "./src/RosLibNode.js",
   "devDependencies": {
     "grunt": "~0.4.1",
     "grunt-browserify": "^3.0.1",
@@ -37,6 +37,7 @@
   "scripts": {
     "test": "grunt test",
     "test-examples": "grunt mochaTest:examples && karma start test/examples/karma.conf.js",
+    "test-tcp": "grunt mochaTest:tcp",
     "publish": "grunt build"
   },
   "repository": {

src/RosLibNode.js

@@ -0,0 +1,8 @@
+/**
+ * ROSLIB Node exclusive extensions 
+ */
+var assign = require('object-assign');
+
+module.exports = assign(require('./RosLib'), {
+  Ros: require('./node/RosTCP.js')
+});

src/core/Ros.js

@@ -2,14 +2,14 @@
  * @author Brandon Alexander - baalexander@gmail.com
  */
 
-var Canvas = require('canvas');
-var Image = Canvas.Image || global.Image;
-var EventEmitter2 = require('eventemitter2').EventEmitter2;
 var WebSocket = require('ws');
+var socketAdapter = require('./SocketAdapter.js');
 
 var Service = require('./Service');
 var ServiceRequest = require('./ServiceRequest');
 
+var assign = require('object-assign');
+var EventEmitter2 = require('eventemitter2').EventEmitter2;
 
 /**
  * Manages connection to the server and all interactions with ROS.
@@ -27,16 +27,16 @@ var ServiceRequest = require('./ServiceRequest');
  */
 function Ros(options) {
   options = options || {};
-  var url = options.url;
   this.socket = null;
   this.idCounter = 0;
+  this.isConnected = false;
 
   // Sets unlimited event listeners.
   this.setMaxListeners(0);
 
   // begin by checking if a URL was given
-  if (url) {
-    this.connect(url);
+  if (options.url) {
+    this.connect(options.url);
   }
 }
 
@@ -48,105 +48,7 @@ Ros.prototype.__proto__ = EventEmitter2.prototype;
  * @param url - WebSocket URL for Rosbridge
  */
 Ros.prototype.connect = function(url) {
-  var that = this;
-
-  /**
-   * Emits a 'connection' event on WebSocket connection.
-   *
-   * @param event - the argument to emit with the event.
-   */
-  function onOpen(event) {
-    that.emit('connection', event);
-  }
-
-  /**
-   * Emits a 'close' event on WebSocket disconnection.
-   *
-   * @param event - the argument to emit with the event.
-   */
-  function onClose(event) {
-    that.emit('close', event);
-  }
-
-  /**
-   * Emits an 'error' event whenever there was an error.
-   *
-   * @param event - the argument to emit with the event.
-   */
-  function onError(event) {
-    that.emit('error', event);
-  }
-
-  /**
-   * If a message was compressed as a PNG image (a compression hack since
-   * gzipping over WebSockets * is not supported yet), this function places the
-   * "image" in a canvas element then decodes the * "image" as a Base64 string.
-   *
-   * @param data - object containing the PNG data.
-   * @param callback - function with params:
-   *   * data - the uncompressed data
-   */
-  function decompressPng(data, callback) {
-    // Uncompresses the data before sending it through (use image/canvas to do so).
-    var image = new Image();
-    // When the image loads, extracts the raw data (JSON message).
-    image.onload = function() {
-      // Creates a local canvas to draw on.
-      var canvas = new Canvas();
-      var context = canvas.getContext('2d');
-
-      // Sets width and height.
-      canvas.width = image.width;
-      canvas.height = image.height;
-
-      // Puts the data into the image.
-      context.drawImage(image, 0, 0);
-      // Grabs the raw, uncompressed data.
-      var imageData = context.getImageData(0, 0, image.width, image.height).data;
-
-      // Constructs the JSON.
-      var jsonData = '';
-      for ( var i = 0; i < imageData.length; i += 4) {
-        // RGB
-        jsonData += String.fromCharCode(imageData[i], imageData[i + 1], imageData[i + 2]);
-      }
-      var decompressedData = JSON.parse(jsonData);
-      callback(decompressedData);
-    };
-    // Sends the image data to load.
-    image.src = 'data:image/png;base64,' + data.data;
-  }
-
-  /**
-   * Parses message responses from rosbridge and sends to the appropriate
-   * topic, service, or param.
-   *
-   * @param message - the raw JSON message from rosbridge.
-   */
-  function onMessage(message) {
-    function handleMessage(message) {
-      if (message.op === 'publish') {
-        that.emit(message.topic, message.msg);
-      } else if (message.op === 'service_response') {
-        that.emit(message.id, message);
-      }
-    }
-
-    var data = JSON.parse(message.data);
-    if (data.op === 'png') {
-      decompressPng(data, function(decompressedData) {
-        handleMessage(decompressedData);
-      });
-    } else {
-      handleMessage(data);
-    }
-  }
-
-  this.socket = new WebSocket(url);
-  this.socket.onopen = onOpen;
-  this.socket.onclose = onClose;
-  this.socket.onerror = onError;
-  this.socket.onmessage = onMessage;
+  this.socket = assign(new WebSocket(url), socketAdapter(this));
 };
 
 /**
@@ -193,7 +95,7 @@ Ros.prototype.callOnConnection = function(message) {
   var that = this;
   var messageJson = JSON.stringify(message);
 
-  if (!this.socket || this.socket.readyState !== WebSocket.OPEN) {
+  if (!this.isConnected) {
     that.once('connection', function() {
       that.socket.send(messageJson);
     });

src/core/SocketAdapter.js

@@ -0,0 +1,114 @@
+/**
+ * Socket event handling utilities for handling events on either
+ * WebSocket and TCP sockets
+ *
+ * Note to anyone reviewing this code: these functions are called
+ * in the context of their parent object, unless bound
+ */
+'use strict';
+
+var Canvas = require('canvas');
+var Image = Canvas.Image || global.Image;
+var WebSocket = require('ws');
+
+/**
+ * If a message was compressed as a PNG image (a compression hack since
+ * gzipping over WebSockets * is not supported yet), this function places the
+ * "image" in a canvas element then decodes the * "image" as a Base64 string.
+ *
+ * @param data - object containing the PNG data.
+ * @param callback - function with params:
+ *   * data - the uncompressed data
+ */
+function decompressPng(data, callback) {
+  // Uncompresses the data before sending it through (use image/canvas to do so).
+  var image = new Image();
+  // When the image loads, extracts the raw data (JSON message).
+  image.onload = function() {
+    // Creates a local canvas to draw on.
+    var canvas = new Canvas();
+    var context = canvas.getContext('2d');
+
+    // Sets width and height.
+    canvas.width = image.width;
+    canvas.height = image.height;
+
+    // Puts the data into the image.
+    context.drawImage(image, 0, 0);
+    // Grabs the raw, uncompressed data.
+    var imageData = context.getImageData(0, 0, image.width, image.height).data;
+
+    // Constructs the JSON.
+    var jsonData = '';
+    for (var i = 0; i < imageData.length; i += 4) {
+      // RGB
+      jsonData += String.fromCharCode(imageData[i], imageData[i + 1], imageData[i + 2]);
+    }
+    callback(JSON.parse(jsonData));
+  };
+  // Sends the image data to load.
+  image.src = 'data:image/png;base64,' + data.data;
+}
+
+/**
+ * Events listeners for a WebSocket or TCP socket to a JavaScript
+ * ROS Client. Sets up Messages for a given topic to trigger an
+ * event on the ROS client.
+ */
+function SocketAdapter(client) {
+  function handleMessage(message) {
+    if (message.op === 'publish') {
+      client.emit(message.topic, message.msg);
+    } else if (message.op === 'service_response') {
+      client.emit(message.id, message);
+    }
+  }
+
+  return {
+    /**
+     * Emits a 'connection' event on WebSocket connection.
+     *
+     * @param event - the argument to emit with the event.
+     */
+    onopen: function onOpen(event) {
+      client.isConnected = true;
+      client.emit('connection', event);
+    },
+
+    /**
+     * Emits a 'close' event on WebSocket disconnection.
+     *
+     * @param event - the argument to emit with the event.
+     */
+    onclose: function onClose(event) {
+      client.isConnected = false;
+      client.emit('close', event);
+    },
+
+    /**
+     * Emits an 'error' event whenever there was an error.
+     *
+     * @param event - the argument to emit with the event.
+     */
+    onerror: function onError(event) {
+      client.emit('error', event);
+    },
+
+    /**
+     * Parses message responses from rosbridge and sends to the appropriate
+     * topic, service, or param.
+     *
+     * @param message - the raw JSON message from rosbridge.
+     */
+    onmessage: function onMessage(message) {
+      var data = JSON.parse(typeof message === 'string' ? message : message.data);
+      if (data.op === 'png') {
+        decompressPng(data, handleMessage);
+      } else {
+        handleMessage(data);
+      }
+    }
+  };
+}
+
+module.exports = SocketAdapter;

src/node/RosTCP.js

@@ -0,0 +1,54 @@
+var Ros = require('../core/Ros');
+var net = require('net');
+var socketAdapter = require('../core/SocketAdapter.js');
+var util = require('util');
+
+/**
+ * Same as core Ros except supports TCP connections
+ */ 
+function RosTCP(options) {
+  options = options || {};
+  if (!options.encoding) {
+    util.debug('ROSLib uses utf8 encoding by default.' +
+      'It would be more efficent to use ascii (if possible)');
+  }
+  this.encoding = options.encoding || 'utf8';
+  Ros.call(this, options);
+
+  if (!this.socket && (options.host || options.port)) {
+    this.connect({
+      host: options.host,
+      port: options.port
+    });
+  }
+}
+
+util.inherits(RosTCP, Ros);
+
+/**
+ * Connects to a live socket
+ *
+ * * url (String|Int|Object): Address and port to connect to (see http://nodejs.org/api/net.html)
+ *     format {host: String, port: Int} or (port:Int), or "host:port"
+ */
+RosTCP.prototype.connect = function(url) {
+  if (typeof url === 'string' && url.slice(0, 5) === 'ws://') {
+    Ros.prototype.connect.call(this, url);
+  } else {
+    var events = socketAdapter(this);
+    this.socket = net.connect(url)
+      .on('data', events.onmessage)
+      .on('close', events.onclose)
+      .on('error', events.onerror)
+      .on('connect', events.onopen);
+    this.socket.setEncoding(this.encoding);
+    this.socket.setTimeout(0);
+
+    // Little hack for call on connection
+    this.socket.send = this.socket.write;
+    // Similarly for close
+    this.socket.close = this.socket.end;
+  }
+};
+
+module.exports = RosTCP;

test/tcp/check-topics.examples.js

@@ -0,0 +1,24 @@
+var expect = require('chai').expect;
+var ROSLIB = require('../..');
+
+var expectedTopics = [
+    // '/turtle1/cmd_vel', '/turtle1/color_sensor', '/turtle1/pose',
+    // '/turtle2/cmd_vel', '/turtle2/color_sensor', '/turtle2/pose',
+    '/tf2_web_republisher/status', '/tf2_web_republisher/feedback',
+    // '/tf2_web_republisher/goal', '/tf2_web_republisher/result',
+    '/fibonacci/feedback', '/fibonacci/status', '/fibonacci/result'
+];
+
+describe('Example topics are live', function(done) {
+    it('getTopics', function(done) {
+        var ros = new ROSLIB.Ros({
+            port: 9090
+        });
+        ros.getTopics(function(topics) {
+            expectedTopics.forEach(function(topic) {
+                expect(topics).to.contain(topic, 'Couldn\'t find topic: ' + topic);
+            });
+            done();
+        });
+    });
+});