How to redirect from an async page function?

[espeoceka]

Hey im not even sure its issue, i might be doing something wrong....

For example:

@ui.page('/logout')
async def logout(request: Request) -> None:
    if await is_authenticated(request):
        await redis.expire(request.session["id"], 0)
        request.session['id'] = None
        return RedirectResponse('/login')
    else:
        return RedirectResponse('/')

It never redirect to anything, but when i remove async it works like intended. Any ideas how to sort this out ?

[falkoschindler]

Thanks for reaching out, @espeoceka!

I was confused at first, since it is working without async. But now I'm actually not sure, why it is working at all...
As the type annotation says, logout is supposed to build a UI and return nothing. But instead it returns a FastAPI response. So logout isn't a NiceGUI page function, but a regular FastAPI endpoint. Therefore it should be decorated with app.get instead of ui.page.

For example, the following code is working with and without async:

@app.get('/redirect')
async def redirect() -> None:
    return RedirectResponse('/')

[ed2050]

It's not stated that RedirectResponse is a fastapi class. Code above doesn't work unless you add this:

from fastapi.responses import RedirectResponse

see https://fastapi.tiangolo.com/uk/advanced/custom-response/#redirectresponse

[falkoschindler]

@rodja and I just noticed that @espeoceka's code example actually should work with the current implementation of ui.page. Therefore I opened an issue #693 to fix it.

[espeoceka]

Hey great that this has been worked on, i found also issue related to redirecting. This looks atrocious on first glance but im trying to make dependency that simply authorize user and if no user profile is found redirects to login......

@ui.page('/user/contact_lists')
async def user_contact_lists(request: Request,client:Client,db_session=Depends(get_db),user_profile=Depends(get_user_profile)):
    while True:
        status = await client.connected(timeout=5)
        if not client.is_waiting_for_connection:
            break
        await asyncio.sleep(1)
    
    if not isinstance(user_profile,User):
        ui.open(f"/login?destination={client.page.path}")

This "charming" loop somehow makes redirection works.... but it cannot be used in dependency due to some pydantic error. I already guessing its not good approach at best. How this should be done ?

PS. I tried to make a dependency that takes Client class but it seems to be impossible due to pydantic error ( Client class added to arguments of get_user_profile )

[rodja]

I think we need to figure out how to make the client created in

nicegui/nicegui/page.py

Line 66 in 3d1ee70

with Client(self) as client:

available to FastAPIs

https://github.com/tiangolo/fastapi/blob/c81e136d75f5ac4252df740b35551cf2afb4c7f1/fastapi/dependencies/utils.py#L546

[falkoschindler]

Annoyingly FastAPI seems to resolve dependencies before entering our page function. Therefore global.get_client() fails with an IndexError if we try to do it like this:

def get_client_id() -> str:
    return globals.get_client().id

@ui.page('/')
def user_contact_lists(client_id=Depends(get_client_id, use_cache=False)):
    print(client_id)

[falkoschindler]

We're still thinking about a way to support FastAPI's dependency injection with our Client object. But in principle it's tricky, because the dependency injection runs before entering the page function, but only the page function creates the client. And if other functions depend on the client (like get_user_profile), it's not clear how to resolve it, because the client depends on the current request.

[espeoceka]

Yea i thought this might be this sad one....

Maybe its possible to declare dependecies on ui.page level instead ? ( they can be solved there and their results can be passed down to function as regular kwargs )

[ysharoiko]

No progress on that?
I have also stucked

#!/usr/bin/env python3.11
#-*- coding: utf-8 -*-

from nicegui import ui, background_tasks
from fastapi.responses import RedirectResponse
import asyncio

@ui.page('/download')
def index_page():
  async def load():
    await asyncio.sleep(3) # fetch data or something else which takes time (must be async)
    
    content.clear() 
    with content:
      ui.markdown('Done. Redirecting ...')

    #ui.add_head_html('''
    #<script>
    #  window.location.href = window.location.protocol + "//" + window.location.host
    #</script>
#  ''')
    ui.open(f"http://google.ru")
    #return RedirectResponse("http://google.ru")
      
  with ui.element("div").style("align-self: center; padding-top:100pt;"):
    with ui.card().style(f"background-color: #dedede, align-items: center;") as content:
      ui.spinner('dots', size='5em', color='#81b983') 
      #size='10em'
      ui.label("Preparing...").style("padding-top:18pt;")

      background_tasks.create(load())

ui.run()

None of above redirecting is working :(