Added plugin mechanism to send any data to the server

rosboard/handlers.py

@@ -9,6 +9,7 @@
 import uuid
 
 from . import __version__
+from plugins import get_plugin_js_files, received_plugin_message
 
 class NoCacheStaticFileHandler(tornado.web.StaticFileHandler):
     def set_extra_headers(self, path):
@@ -49,6 +50,7 @@ def open(self):
         self.write_message(json.dumps([ROSBoardSocketHandler.MSG_SYSTEM, {
             "hostname": socket.gethostname(),
             "version": __version__,
+            "plugin_js_files": get_plugin_js_files()
         }], separators=(',', ':')))
 
     def on_close(self):
@@ -142,7 +144,7 @@ def on_message(self, message):
             self.latency = (received_pong_time - self.last_ping_times[argv[1].get(ROSBoardSocketHandler.PONG_SEQ, 0) % 1024]) / 2
             if self.latency > 1000.0:
                 self.node.logwarn("socket %s has high latency of %.2f ms" % (str(self.id), self.latency))
-            
+
             if self.latency > 10000.0:
                 self.node.logerr("socket %s has excessive latency of %.2f ms; closing connection" % (str(self.id), self.latency))
                 self.close()
@@ -187,13 +189,23 @@ def on_message(self, message):
             except KeyError:
                 print("KeyError trying to remove sub")
 
+        # client wants to send something to a plugin
+        elif argv[0] == ROSBoardSocketHandler.MSG_PLUGIN_MESSAGE:
+            if len(argv) != 2 or type(argv[1]) is not dict:
+                print("error: plugin_message: bad: %s" % message)
+                return
+            name = argv[1].get("name")
+            msg = argv[1].get("message")
+            received_plugin_message(name, msg)
+
 ROSBoardSocketHandler.MSG_PING = "p";
 ROSBoardSocketHandler.MSG_PONG = "q";
 ROSBoardSocketHandler.MSG_MSG = "m";
 ROSBoardSocketHandler.MSG_TOPICS = "t";
 ROSBoardSocketHandler.MSG_SUB = "s";
 ROSBoardSocketHandler.MSG_SYSTEM = "y";
 ROSBoardSocketHandler.MSG_UNSUB = "u";
+ROSBoardSocketHandler.MSG_PLUGIN_MESSAGE = "pm";
 
 ROSBoardSocketHandler.PING_SEQ = "s";
 ROSBoardSocketHandler.PONG_SEQ = "s";

rosboard/html/js/index.js

@@ -24,21 +24,6 @@ var snackbarContainer = document.querySelector('#demo-toast-example');
 
 let subscriptions = {};
 
-if(window.localStorage && window.localStorage.subscriptions) {
-  if(window.location.search && window.location.search.indexOf("reset") !== -1) {
-    subscriptions = {};
-    updateStoredSubscriptions();
-    window.location.href = "?";
-  } else {
-    try {
-      subscriptions = JSON.parse(window.localStorage.subscriptions);
-    } catch(e) {
-      console.log(e);
-      subscriptions = {};
-    }
-  }
-}
-
 let $grid = null;
 $(() => {
   $grid = $('.grid').masonry({
@@ -75,13 +60,6 @@ function newCard() {
   return card;
 }
 
-let onOpen = function() {
-  for(let topic_name in subscriptions) {
-    console.log("Re-subscribing to " + topic_name);
-    initSubscribe({topicName: topic_name, topicType: subscriptions[topic_name].topicType});
-  }
-}
-
 let onSystem = function(system) {
   if(system.hostname) {
     console.log("hostname: " + system.hostname);
@@ -92,6 +70,30 @@ let onSystem = function(system) {
     console.log("server version: " + system.version);
     versionCheck(system.version);
   }
+
+  for (let idx in system.plugin_js_files) {
+      importJsOnce(system.plugin_js_files[idx]);
+  }
+
+  if(window.localStorage && window.localStorage.subscriptions) {
+    if(window.location.search && window.location.search.indexOf("reset") !== -1) {
+      subscriptions = {};
+      updateStoredSubscriptions();
+      window.location.href = "?";
+    } else {
+      try {
+        subscriptions = JSON.parse(window.localStorage.subscriptions);
+      } catch(e) {
+        console.log(e);
+        subscriptions = {};
+      }
+    }
+  }
+
+  for(let topic_name in subscriptions) {
+    console.log("Re-subscribing to " + topic_name);
+    initSubscribe({topicName: topic_name, topicType: subscriptions[topic_name].topicType});
+  }
 }
 
 let onMsg = function(msg) {
@@ -108,7 +110,7 @@ let currentTopics = {};
 let currentTopicsStr = "";
 
 let onTopics = function(topics) {
-  
+
   // check if topics has actually changed, if not, don't do anything
   // lazy shortcut to deep compares, might possibly even be faster than
   // implementing a deep compare due to
@@ -117,12 +119,12 @@ let onTopics = function(topics) {
   if(newTopicsStr === currentTopicsStr) return;
   currentTopics = topics;
   currentTopicsStr = newTopicsStr;
-  
+
   let topicTree = treeifyPaths(Object.keys(topics));
-  
+
   $("#topics-nav-ros").empty();
   $("#topics-nav-system").empty();
-  
+
   addTopicTreeToNav(topicTree[0], $('#topics-nav-ros'));
 
   $('<a></a>')
@@ -195,7 +197,7 @@ function initSubscribe({topicName, topicType}) {
     subscriptions[topicName] = {
       topicType: topicType,
     }
-  }  
+  }
   currentTransport.subscribe({topicName: topicName});
   if(!subscriptions[topicName].viewer) {
     let card = newCard();
@@ -217,7 +219,6 @@ let currentTransport = null;
 function initDefaultTransport() {
   currentTransport = new WebSocketV1Transport({
     path: "/rosboard/v1",
-    onOpen: onOpen,
     onMsg: onMsg,
     onTopics: onTopics,
     onSystem: onSystem,
@@ -236,7 +237,7 @@ function treeifyPaths(paths) {
         r[name] = {result: []};
         r.result.push({name, children: r[name].result})
       }
-      
+
       return r[name];
     }, level)
   });

rosboard/html/js/transports/WebSocketV1Transport.js

@@ -8,25 +8,25 @@ class WebSocketV1Transport {
       this.onSystem = onSystem ? onSystem.bind(this) : null;
       this.ws = null;
     }
-  
+
     connect() {
       var protocolPrefix = (window.location.protocol === 'https:') ? 'wss:' : 'ws:';
       let abspath = protocolPrefix + '//' + location.host + this.path;
-  
+
       let that = this;
-  
+
       this.ws = new WebSocket(abspath);
-  
+
       this.ws.onopen = function(){
         console.log("connected");
         if(that.onOpen) that.onOpen(that);
       }
-      
+
       this.ws.onclose = function(){
         console.log("disconnected");
         if(that.onClose) that.onClose(that);
       }
-  
+
       this.ws.onmessage = function(wsmsg) {
         let data = [];
         try {
@@ -39,7 +39,7 @@ class WebSocketV1Transport {
         }
 
         let wsMsgType = data[0];
-  
+
         if(wsMsgType === WebSocketV1Transport.MSG_PING) {
           this.send(JSON.stringify([WebSocketV1Transport.MSG_PONG, {
             [WebSocketV1Transport.PONG_SEQ]: data[1][WebSocketV1Transport.PING_SEQ],
@@ -52,27 +52,32 @@ class WebSocketV1Transport {
         else console.log("received unknown message: " + wsmsg.data);
       }
     }
-  
+
     isConnected() {
       return (this.ws && this.ws.readyState === this.ws.OPEN);
     }
-  
+
     subscribe({topicName, maxUpdateRate = 24.0}) {
       this.ws.send(JSON.stringify([WebSocketV1Transport.MSG_SUB, {topicName: topicName, maxUpdateRate: maxUpdateRate}]));
     }
 
     unsubscribe({topicName}) {
       this.ws.send(JSON.stringify([WebSocketV1Transport.MSG_UNSUB, {topicName: topicName}]));
     }
+
+    send_plugin_message(name, message) {
+        this.ws.send(JSON.stringify([WebSocketV1Transport.MSG_PLUGIN_MESSAGE, { name: name, message: message }]));
+    }
   }
-  
+
   WebSocketV1Transport.MSG_PING = "p";
   WebSocketV1Transport.MSG_PONG = "q";
   WebSocketV1Transport.MSG_MSG = "m";
   WebSocketV1Transport.MSG_TOPICS = "t";
   WebSocketV1Transport.MSG_SUB = "s";
   WebSocketV1Transport.MSG_SYSTEM = "y";
   WebSocketV1Transport.MSG_UNSUB = "u";
+  WebSocketV1Transport.MSG_PLUGIN_MESSAGE = "pm";
 
   WebSocketV1Transport.PING_SEQ= "s";
   WebSocketV1Transport.PONG_SEQ = "s";

rosboard/html/js/viewers/meta/Viewer.js

@@ -222,9 +222,14 @@ Viewer.onClose = (viewerInstance) => { console.log("not implemented; override ne
 Viewer.onSwitchViewer = (viewerInstance, newViewerType) => { console.log("not implemented; override necessary"); }
 
 // not to be overwritten by child class!
-Viewer.registerViewer = (viewer) => {
+Viewer.registerViewer = (viewer, toTop=false) => {
   // registers a viewer. the viewer child class calls this at the end of the file to register itself
-  Viewer._viewers.push(viewer);
+  if (toTop) {
+    // call with true if it's a plugin
+    Viewer._viewers.unshift(viewer);
+  } else {
+    Viewer._viewers.push(viewer);
+  }
 };
 
 // not to be overwritten by child class!

rosboard/plugins/__init__.py

@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+
+import pathlib
+import pkgutil
+import sys
+import traceback
+
+
+_plugins = {}
+
+def _load_plugins(dirname: str):
+    global _plugins
+    for importer, package_name, _ in pkgutil.iter_modules([dirname]):
+        full_package_name = '%s.%s' % (dirname, package_name)
+        if full_package_name in sys.modules:
+            print(f'Plugin "{full_package_name}" not loaded, already present. Check name clashes.')
+            continue
+
+        try:
+            module = importer.find_module(package_name).load_module(package_name)
+            _plugins[package_name] = module
+        except Exception as e:
+            traceback.print_exception(e)
+
+def get_plugin_js_files():
+    global _plugins
+    js_files = []
+
+    for plugin in _plugins.values():
+        js_files.extend(plugin.js_files)
+
+    return js_files
+
+def received_plugin_message(name: str, message):
+    global _plugins
+    if name not in _plugins:
+        print(f'Plugin unknown "{name}"')
+        return
+
+    try:
+        _plugins[name].receive(message)
+    except Exception as e:
+        traceback.print_exception(e)
+
+_load_plugins(str(pathlib.Path(__file__).parent.resolve()))

rosboard/plugins/plugin.md

@@ -0,0 +1,50 @@
+Example of a possible plugin with ros support:
+
+```python
+#!/usr/bin/env python3
+
+import os
+import pathlib
+import sys
+
+sys.path.append(f"{pathlib.Path(__file__).parent.resolve()}/.")
+if os.environ.get("ROS_VERSION") == "1":
+    import rospy  # ROS1
+elif os.environ.get("ROS_VERSION") == "2":
+    import rospy2 as rospy  # ROS2
+else:
+    print("ROS not detected. Please source your ROS environment\n(e.g. 'source /opt/ros/DISTRO/setup.bash')")
+    exit(1)
+
+from std_msgs.msg import String
+
+
+class DummyPlugin:
+
+    def __init__(self):
+        self.publisher = rospy.Publisher('dummy_topic', String)
+
+    def receive(self, message):
+        msg = String()
+        msg.data = str(message)
+        self.publisher.publish(msg)
+
+
+# This is the most important function for all plugins,
+# it's called when a message from the client is sent towards the backend
+def receive(message):
+    global _instance
+    if _instance == None:
+        _instance = DummyPlugin()
+
+    _instance.receive(message)
+
+_instance = None
+
+# Add all javascript files which are needed for this plugin on the client side:
+# e.g. "js/plugins/dummy.js", "js/viewer/dummy.js"
+# From client side use the javascript function, like this:
+# currentTransport.send_plugin_message("dummy", "myImportantMessage"})
+# currentTransport.send_plugin_message("dummy", {myKey: "myImportantMessage"})
+js_files = []
+```