provide observable set "app.urls"

to access the list of urls on which the app is available

nicegui/air.py

@@ -55,6 +55,7 @@ class Air:
 
         @self.relay.on('ready')
         def on_ready(data: Dict[str, Any]) -> None:
+            globals.app.urls.add(data['device_url'])
             print(f'NiceGUI is on air at {data["device_url"]}', flush=True)
 
         @self.relay.on('error')

nicegui/app.py

@@ -7,6 +7,7 @@ from fastapi.staticfiles import StaticFiles
 
 from . import globals, helpers  # pylint: disable=redefined-builtin
 from .native import Native
+from .observables import ObservableSet
 from .storage import Storage
 
 
@@ -16,6 +17,7 @@ class App(FastAPI):
         super().__init__(**kwargs)
         self.native = Native()
         self.storage = Storage()
+        self.urls = ObservableSet()
 
     def on_connect(self, handler: Union[Callable, Awaitable]) -> None:
         """Called every time a new client connects to NiceGUI.

nicegui/welcome.py

@@ -36,10 +36,11 @@ async def print_message() -> None:
     loop = asyncio.get_running_loop()
     ips = set((await loop.run_in_executor(None, get_all_ips)) if host == '0.0.0.0' else [])
     ips.discard('127.0.0.1')
-    addresses = [(f'http://{ip}:{port}' if port != '80' else f'http://{ip}') for ip in ['localhost'] + sorted(ips)]
-    if len(addresses) >= 2:
-        addresses[-1] = 'and ' + addresses[-1]
+    urls = [(f'http://{ip}:{port}' if port != '80' else f'http://{ip}') for ip in ['localhost'] + sorted(ips)]
+    globals.app.urls.update(urls)
+    if len(urls) >= 2:
+        urls[-1] = 'and ' + urls[-1]
     extra = ''
     if 'netifaces' not in globals.optional_features:
         extra = ' (install netifaces to show all IPs and speedup this message)'
-    print(f'on {", ".join(addresses)}' + extra, flush=True)
+    print(f'on {", ".join(urls)}' + extra, flush=True)