me.navigate() in page load does not work some time

[programus]

Describe the bug

import mesop as me


@me.page(path='/')
def main_page():
    me.text("This is the main page.")
    me.navigate('/login')


@me.page(path='/login')
def login_page():
    me.text("This is the login page.")

With the code above, while I access root path, the URL in address bar changed to /login, but the page content does not change some time.

If I put a breakpoint in the login_page(), that would not stop.

To Reproduce
Steps to reproduce the behavior:

1. Access / using the above code.

Expected behavior
The page really redirect to /login.

Screenshots

Desktop System Info

• OS: macOS
• Browser Chrome, Ark
• Version
  • Chrome: 142.0.7444.60 (Official Build) (arm64)
  • Ark: Version 1.120.0 (70500) Chromium Engine Version 142.0.7444.135

Additional context
Tried both mesop main.py and gunicorn.

[programus]

import mesop as me


def redirect_to_login(event: me.LoadEvent):
    me.navigate('/login')

@me.page(path='/', on_load=redirect_to_login)
def main_page():
    me.text("This is the main page.")


@me.page(path='/login')
def login_page():
    me.text("This is the login page.")

This code also has the same problem.

[richard-to]

Ah I see. That's an interesting issue. I don't think we accounted for this use case. I'll need to look at the me.navigate code and see why it's not handling this situation correctly in all cases.

[richard-to]

Temporary solutions:

• For now you could create a web component that forces the redirect. This would be a normal redirect that would reload the page
• Another option, depending on your set up and use case is to add it at the server level. But looking at your use of / and /login, it seems you're implementing an auth redirect, so this option problem wouldn't work for you.

[programus]

@richard-to Thank you for your response.

The real life use case is if the user is not logged in, navigate to the login page, which I consider as a quite common use case for a app with login feature. I just removed the check of the login status to minimize the reproduction example.

Unfortunately, there is another state related issue force me to switch to other more stable (but more complex) solution (Svelte + FastAPI) instead of keep using mesop in our project. So, I may not follow this issue very often in the future.

[richard-to]

Ok sounds good. Yeah, definitely use the tool you feel is best for your needs. Either way, the feedback is appreciated. I agree that this auth/login use cases are pretty critical and Mesop needs much better support for those use cases.