fix page examples; fix on_connect for non-shared pages

main.py

@@ -584,11 +584,13 @@ with example(async_handlers):
 h3('Pages and Routes')
 
 with example(ui.page):
-    with ui.page('/other_page'):
+    @ui.page('/other_page')
+    def other_page():
         ui.label('Welcome to the other side')
         ui.link('Back to main page', '#page')
 
-    with ui.page('/dark_page', dark=True):
+    @ui.page('/dark_page', dark=True)
+    def dark_page():
         ui.label('Welcome to the dark side')
         ui.link('Back to main page', '#page')
 
@@ -596,11 +598,12 @@ with example(ui.page):
     ui.link('Visit dark page', 'dark_page')
 
 with example(ui.open):
-    with ui.page('/yet_another_page') as other:
+    @ui.page('/yet_another_page')
+    def yet_another_page():
         ui.label('Welcome to yet another page')
         ui.button('RETURN', on_click=lambda e: ui.open('#open', e.socket))
 
-    ui.button('REDIRECT', on_click=lambda e: ui.open(other, e.socket))
+    ui.button('REDIRECT', on_click=lambda e: ui.open('yet_another_page', e.socket))
 
 add_route = '''#### Route
 
@@ -655,9 +658,11 @@ with example(sessions):
         id_counter[request.session_id] += 1
         visits.set_text(f'{len(id_counter)} unique views ({sum(id_counter.values())} overall) since {creation}')
 
-    with ui.page('/session_demo', on_connect=handle_connection) as page:
+    @ui.page('/session_demo', on_connect=handle_connection)
+    def session_demo():
+        global visits
         visits = ui.label()
 
-    ui.link('Visit session demo', page)
+    ui.link('Visit session demo', 'session_demo')
 
 ui.run()

nicegui/elements/page.py

@@ -1,10 +1,12 @@
+from __future__ import annotations
+
 import asyncio
 import inspect
 import time
 import uuid
 from dataclasses import dataclass
 from functools import wraps
-from typing import Callable, Optional
+from typing import Awaitable, Callable, Optional
 
 import justpy as jp
 from addict import Dict
@@ -17,9 +19,19 @@ from ..helpers import is_coroutine
 
 @dataclass
 class PageBuilder:
-    function: Callable
+    function: Callable[[], Awaitable[Page]]
     shared: bool
 
+    _shared_page: Optional[Page] = None
+
+    async def build(self) -> None:
+        assert self.shared
+        self._shared_page = await self.function()
+
+    async def route_function(self, request: Request) -> Page:
+        page = self._shared_page if self.shared else await self.function()
+        return await page._route_function(request)
+
 
 class Page(jp.QuasarPage):
 

nicegui/nicegui.py

@@ -30,9 +30,8 @@ async def startup():
     jp.Route("/{path:path}", error404, last=True)
     for route, page_builder in globals.page_builders.items():
         if page_builder.shared:
-            jp.Route(route, (await page_builder.function())._route_function)
-        else:
-            jp.Route(route, page_builder.function)
+            page_builder.build()
+        jp.Route(route, page_builder.route_function)
     globals.tasks.extend(create_task(t.coro, name=t.name) for t in Timer.prepared_coroutines)
     Timer.prepared_coroutines.clear()
     globals.tasks.extend(create_task(t, name='startup task')