Routing submodule functions using FastAPI's APIRouter

Question

I have the following in my main.py:

from fastapi import FastAPI, Request
from fastapi.responses import HTMLResponse
from fastapi.middleware.gzip import GZipMiddleware
from fastapi.templating import Jinja2Templates
from fastapi.staticfiles import StaticFiles
from my_app.web.views import default

app = FastAPI()
app.add_middleware(GZipMiddleware, minimum_size=500)
app.include_router(default.router)
#app.include_router(data_mgr_view.router)

app.mount("/static", StaticFiles(directory="static"), name="static")
app.mount("/templates", Jinja2Templates(directory="templates"), name="templates")


@app.get('/test')
async def test():
    return "test successful"

This works fine. I can hit the URL at localhost:5000/test and it returns expected string. Now I have this file default.py whose handlers I want to be based off root:

import sys, traceback
import pandas as pd
from fastapi import APIRouter, Request, Query
from my_app.web.models.response_data import ResponseData
from my_app.data.providers.internals_provider import MktInternalsProvider
from my_app.config import tmplts

router = APIRouter(prefix="")

@router.route('/')
async def root(request: Request):
    context = {"title":"Playground", "content":f"Place for my charts, studies, etc..."}
    return tmplts.TemplateResponse(request=request, name="index.html", context=context)

@router.route('/test2')
async def test2():
    return "test2 success"

The first method works fine when I hit localhost:5000/. The second method throws an exception when I hit localhost:5000/test2:

Traceback (most recent call last):
  File "/usr/local/lib/python3.11/site-packages/uvicorn/protocols/http/httptools_impl.py", line 411, in run_asgi
    result = await app(  # type: ignore[func-returns-value]
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/uvicorn/middleware/proxy_headers.py", line 69, in __call__
    return await self.app(scope, receive, send)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/fastapi/applications.py", line 1054, in __call__
    await super().__call__(scope, receive, send)
  File "/usr/local/lib/python3.11/site-packages/starlette/applications.py", line 123, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.11/site-packages/starlette/middleware/errors.py", line 186, in __call__
    raise exc
  File "/usr/local/lib/python3.11/site-packages/starlette/middleware/errors.py", line 164, in __call__
    await self.app(scope, receive, _send)
  File "/usr/local/lib/python3.11/site-packages/starlette/middleware/gzip.py", line 24, in __call__
    await responder(scope, receive, send)
  File "/usr/local/lib/python3.11/site-packages/starlette/middleware/gzip.py", line 44, in __call__
    await self.app(scope, receive, self.send_with_gzip)
  File "/usr/local/lib/python3.11/site-packages/starlette/middleware/exceptions.py", line 65, in __call__
    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
  File "/usr/local/lib/python3.11/site-packages/starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "/usr/local/lib/python3.11/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "/usr/local/lib/python3.11/site-packages/starlette/routing.py", line 756, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.11/site-packages/starlette/routing.py", line 776, in app
    await route.handle(scope, receive, send)
  File "/usr/local/lib/python3.11/site-packages/starlette/routing.py", line 297, in handle
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.11/site-packages/starlette/routing.py", line 77, in app
    await wrap_app_handling_exceptions(app, request)(scope, receive, send)
  File "/usr/local/lib/python3.11/site-packages/starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "/usr/local/lib/python3.11/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "/usr/local/lib/python3.11/site-packages/starlette/routing.py", line 72, in app
    response = await func(request)
                     ^^^^^^^^^^^^^
TypeError: test2() takes 0 positional arguments but 1 was given

async def test2(): -> async def test2(request : Request): — sahasrara62
– sahasrara62, Commented May 12, 2024 at 7:15

Chris · Accepted Answer · 2024-12-05 19:01:55Z

2

When using APIRouter (see APIRouter class docs as well), you shouldn't be using the route decorator/method (which, by the way, appears to be deprecated in Starlette's source code, and its usage is discouraged).

You should instead use the api_route decorator. Example:

from fastapi import FastAPI
from fastapi import APIRouter

router = APIRouter()

@router.api_route('/')
async def root():
    return {"op": "root"}

    
app = FastAPI()
app.include_router(router)

The default HTTP method allowed for that decorator is GET, but you could customize it as desired, using the methods parameter in the decorator. Example:

@router.api_route('/', methods=["GET", "POST"])

Alternatively, you could simply use @router.get, @router.post, etc., decorators as usual. Example:

@router.get('/')
@router.post('/')

I would highly recommend having a look at this answer, this answer, as well as this answer and this answer, which are related to the subject and should prove helpful.

edited Dec 5, 2024 at 19:01

answered May 11, 2024 at 8:37

Chris

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2 Comments

mike01010 Over a year ago

that worked. i was following what i thought was latest docs. thanks much!

Rauf Dec 9, 2024 at 3:14

Valid answer, PSF needs to really take care of their error messaging.

Tarique · Accepted Answer · 2024-05-11 08:08:51Z

0

this will work: Provide a method with router like get or post

@router.get('/test2')
async def test2():
    return "test2 success"

answered May 11, 2024 at 8:08

Tarique

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