AssertionError when reloading the page

[falkoschindler]

When running the following script

#!/usr/bin/env python3
import justpy as jp

wp = jp.WebPage()
wp.add(jp.Div(text='Hello, world!'))

jp.justpy(lambda: wp)

and reloading the page twice, I get a 500 Server Error and the following traceback:

Traceback (most recent call last):
  File "/opt/homebrew/lib/python3.10/site-packages/uvicorn/protocols/http/h11_impl.py", line 366, in run_asgi
    result = await app(self.scope, self.receive, self.send)
  File "/opt/homebrew/lib/python3.10/site-packages/uvicorn/middleware/proxy_headers.py", line 75, in __call__
    return await self.app(scope, receive, send)
  File "/opt/homebrew/lib/python3.10/site-packages/starlette/applications.py", line 124, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/opt/homebrew/lib/python3.10/site-packages/starlette/middleware/errors.py", line 184, in __call__
    raise exc
  File "/opt/homebrew/lib/python3.10/site-packages/starlette/middleware/errors.py", line 162, in __call__
    await self.app(scope, receive, _send)
  File "/opt/homebrew/lib/python3.10/site-packages/starlette/middleware/gzip.py", line 24, in __call__
    await responder(scope, receive, send)
  File "/opt/homebrew/lib/python3.10/site-packages/starlette/middleware/gzip.py", line 43, in __call__
    await self.app(scope, receive, self.send_with_gzip)
  File "/opt/homebrew/lib/python3.10/site-packages/starlette/exceptions.py", line 93, in __call__
    raise exc
  File "/opt/homebrew/lib/python3.10/site-packages/starlette/exceptions.py", line 82, in __call__
    await self.app(scope, receive, sender)
  File "/opt/homebrew/lib/python3.10/site-packages/starlette/routing.py", line 670, in __call__
    await route.handle(scope, receive, send)
  File "/opt/homebrew/lib/python3.10/site-packages/starlette/routing.py", line 266, in handle
    await self.app(scope, receive, send)
  File "/opt/homebrew/lib/python3.10/site-packages/starlette/endpoints.py", line 42, in dispatch
    response = await handler(request)
  File "/Users/falko/Downloads/justpy/justpy/justpy.py", line 180, in get
    assert len(load_page) > 0 or load_page.html, '\u001b[47;1m\033[93mWeb page is empty, add components\033[0m'
AssertionError: Web page is empty, add components

Could it have something to do with #354?

Tested with Chrome or Firefox on 02e3d9f

[WolfgangFahl]

I am in favor of making the old behavior optional which shouldn't be to much work since the reloading now is in

function reload_site() {
        if (!reload_started) {
            console.log("Reloading site...");
            reload_started = true;
            setTimeout(try_reload_site, reload_timeout);
        }
    }

versus

+            let ok_to_reload = confirm('Page needs to be reloaded, click OK to reload');
+            if (ok_to_reload) window.location.reload();

[falkoschindler]

Apparently this behavior is not new. JustPy doesn't seem to like reusing wp objects.

[elimintz]

The reason for that is that justpy would not scale if the memory needed to hold each WebPage on the server were not reclaimed when the page in the browser is closed.

If you don't want the wp object deleted when the browser page is closed use the delete_flag:

import justpy as jp

wp = jp.WebPage(delete_flag=False)
wp.add(jp.Div(text='Hello, world!'))

jp.justpy(lambda: wp)