Dynamic server address:port for the client websocket

README.md

@@ -9,7 +9,7 @@
 </h2>
 
 <p align="center" style="white-space:pre">
-Remi is a GUI library for Python applications that gets rendered in web browsers. 
+Remi is a GUI library for Python applications that gets rendered in web browsers.
 This allows you to access your interface locally and remotely.
 </p>
 
@@ -166,7 +166,7 @@ Run the script. If it's all OK the GUI will be opened automatically in your brow
 You can customize optional parameters in the `start` call like:
 
 ```py
-start(MyApp, address='127.0.0.1', port=8081, multiple_instance=False, enable_file_cache=True, update_interval=0.1, start_browser=True)
+start(MyApp, address='127.0.0.1', port=8081, multiple_instance=False, enable_file_cache=True, update_interval=0.1, start_browser=True, dynamic_web_address=True)
 ```
 
 Parameters:
@@ -184,6 +184,8 @@ Additional Parameters:
 - certfile: SSL certificate filename
 - keyfile: SSL key file
 - ssl_version: authentication version (i.e. ssl.PROTOCOL_TLSv1_2). If None disables SSL encryption
+- dynamic_web_address: set it to `True` if the server is not aware of the IP address and the URL the user will be opening the app with.
+If so, the JavaScript code will use hostname and port in the browser. This parameter is `False` by default.
 
 All widgets constructors accept two standards**kwargs that are:
 - width: can be expressed as int (and is interpreted as a pixel) or as str (and you can specify the measuring unit like '10%')
@@ -312,9 +314,10 @@ Remote access
 ===
 If you are using your REMI app remotely, with a DNS and behind a firewall, you can specify special parameters in the `start` call:
 - **port**: HTTP server port. Don't forget to NAT this port on your router;
+- **dynamic_web_address**: set to `True` if the JavaScript code should use the actual URL's host and port for connecting back to the app, instead of provided IP address. This parameter is `False` by default.
 
 ```py
-start(MyApp, address='0.0.0.0', port=8081)
+start(MyApp, address='0.0.0.0', port=8081, dynamic_web_address=True)
 ```
 
 

remi/gui.py

@@ -1399,7 +1399,17 @@ def set_internal_js(self, app_identifier, net_interface_ip, pending_messages_que
 
                     var self = this;
                     try{
-                        this._ws = new WebSocket(ws_wss + '://%(host)s/');
+                        host = '%(host)s'
+                        if (host !== ''){
+                            wss_url = `${ws_wss}://${host}/`
+                        }
+                        else{
+                            host = document.location.host;
+                            pathname = document.location.pathname;
+                            wss_url = `${ws_wss}://${document.location.host}${pathname}`;
+                        }
+
+                        this._ws = new WebSocket(wss_url);
                         console.debug('opening websocket');
 
                         this._ws.onopen = function(evt){

remi/server.py

@@ -437,8 +437,8 @@ def _instance(self):
             self._need_update_flag = client._need_update_flag
             if hasattr(client, '_update_thread'):
                 self._update_thread = client._update_thread
-                
-        net_interface_ip = self._net_interface_ip()
+
+        net_interface_ip = self._net_interface_ip() if not self.server.dynamic_web_address else ''
         websocket_timeout_timer_ms = str(self.server.websocket_timeout_timer_ms)
         pending_messages_queue_length = str(self.server.pending_messages_queue_length)
         self.page.children['head'].set_internal_js(str(id(self)), net_interface_ip, pending_messages_queue_length, websocket_timeout_timer_ms)
@@ -794,7 +794,9 @@ class ThreadedHTTPServer(socketserver.ThreadingMixIn, HTTPServer):
     def __init__(self, server_address, RequestHandlerClass,
                  auth, multiple_instance, enable_file_cache, update_interval,
                  websocket_timeout_timer_ms, pending_messages_queue_length,
-                 title, server_starter_instance, certfile, keyfile, ssl_version, *userdata):
+                 title, server_starter_instance, certfile, keyfile, ssl_version,
+                 dynamic_web_address,
+                 *userdata):
         HTTPServer.__init__(self, server_address, RequestHandlerClass)
         self.auth = auth
         self.multiple_instance = multiple_instance
@@ -804,6 +806,7 @@ def __init__(self, server_address, RequestHandlerClass,
         self.pending_messages_queue_length = pending_messages_queue_length
         self.title = title
         self.server_starter_instance = server_starter_instance
+        self.dynamic_web_address = dynamic_web_address
         self.userdata = userdata
 
         self.certfile = certfile
@@ -817,8 +820,8 @@ class Server(object):
     # noinspection PyShadowingNames
     def __init__(self, gui_class, title='', start=True, address='127.0.0.1', port=0, username=None, password=None,
                  multiple_instance=False, enable_file_cache=True, update_interval=0.1, start_browser=True,
-                 websocket_timeout_timer_ms=1000, pending_messages_queue_length=1000, 
-                 certfile=None, keyfile=None, ssl_version=None,  userdata=()):
+                 websocket_timeout_timer_ms=1000, pending_messages_queue_length=1000,
+                 certfile=None, keyfile=None, ssl_version=None,  userdata=(), dynamic_web_address=False):
 
         self._gui = gui_class
         self._title = title or gui_class.__name__
@@ -837,6 +840,7 @@ def __init__(self, gui_class, title='', start=True, address='127.0.0.1', port=0,
         self._keyfile = keyfile
         self._ssl_version = ssl_version
         self._userdata = userdata
+        self._dynamic_web_address = dynamic_web_address
         if username and password:
             self._auth = base64.b64encode(encode_text("%s:%s" % (username, password)))
         else:
@@ -866,8 +870,9 @@ def start(self):
         self._sserver = ThreadedHTTPServer((self._address, self._sport), self._gui, self._auth,
                                            self._multiple_instance, self._enable_file_cache,
                                            self._update_interval, self._websocket_timeout_timer_ms,
-                                           self._pending_messages_queue_length, self._title, 
-                                           self, self._certfile, self._keyfile, self._ssl_version, *self._userdata)
+                                           self._pending_messages_queue_length, self._title,
+                                           self, self._certfile, self._keyfile, self._ssl_version, self._dynamic_web_address,
+                                           *self._userdata)
         shost, sport = self._sserver.socket.getsockname()[:2]
         self._log.info('Started httpserver http://%s:%s/'%(shost,sport))
         # when listening on multiple net interfaces the browsers connects to localhost