🐛 Fix removing body from status codes that do not support it

[tiangolo]

🐛 Fix removing body from status codes that do not support it

This is related to this issue here: #4050

Related to this issue in Starlette: encode/starlette#1764

And related to this PR in Starlette: encode/starlette#1765

This removes fastapi.openapi.constants.STATUS_CODES_WITH_NO_BODY, it is replaced by a function in utils.

[codecov]

Codecov Report

Merging #5145 (ca239a6) into master (a0fd613) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #5145   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          532       532           
  Lines        13672     13684   +12     
=========================================
+ Hits         13672     13684   +12     

Impacted Files	Coverage Δ
fastapi/openapi/constants.py	100.00% <ø> (ø)
fastapi/openapi/utils.py	100.00% <100.00%> (ø)
fastapi/routing.py	100.00% <100.00%> (ø)
fastapi/utils.py	100.00% <100.00%> (ø)
tests/test_response_code_no_body.py	100.00% <100.00%> (ø)

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[github-actions]

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[Kyle-sandeman-mrdfood]

Good day, I may file an issue if you'd like but this commit introduces a regression

Previously you could do this

responses = {"4XX": {"Model": SomeModel}}
app = FastAPI(..., responses=responses)

As per https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.2.md#patterned-fields-1

As of this commit/PR it throws an error upon adding a new router:

Traceback (most recent call last):
  File "service.py", line 82, in <module>
    app.include_router(auth_router, prefix=f'{BASE}/auth')
  File "/usr/local/lib/python3.8/site-packages/fastapi/applications.py", line 420, in include_router
    self.router.include_router(
  File "/usr/local/lib/python3.8/site-packages/fastapi/routing.py", line 734, in include_router
    self.add_api_route(
  File "/usr/local/lib/python3.8/site-packages/fastapi/routing.py", line 561, in add_api_route
    route = route_class(
  File "/usr/local/lib/python3.8/site-packages/fastapi/routing.py", line 418, in __init__
    assert is_body_allowed_for_status_code(
  File "/usr/local/lib/python3.8/site-packages/fastapi/utils.py", line 24, in is_body_allowed_for_status_code
    current_status_code = int(status_code)
ValueError: invalid literal for int() with base 10: '4XX'

(similar to #5166 (comment))
I can confirm this works in fastapi[all]~=0.75.0 (which I have pinned in another repo)

[tiangolo]

Hey @Kyle-sandeman-mrdfood, I just tried a lot of things to replicate your problem, but I can't seem to make it "break".

Maybe it was fixed in a recent release. If you are still having problems, please create a new issue.

Here's the example app I used, based on the docs to extend OpenAPI responses and adding a 5XX group of responses.

from typing import Union

from fastapi import FastAPI, APIRouter
from fastapi.responses import FileResponse
from pydantic import BaseModel


class Item(BaseModel):
    id: str
    value: str


responses = {
    404: {"description": "Item not found"},
    302: {"description": "The item was moved"},
    403: {"description": "Not enough privileges"},
    "5XX": {"description": "Server errors"},
}


app = FastAPI()
router = APIRouter()

@router.get(
    "/items/{item_id}",
    response_model=Item,
    responses={**responses, 200: {"content": {"image/png": {}}}},
)
async def read_item(item_id: str, img: Union[bool, None] = None):
    if img:
        return FileResponse("image.png", media_type="image/png")
    else:
        return {"id": "foo", "value": "there goes my hero"}


app.include_router(router)

[Kyle-sandeman-mrdfood]

Hi again, it may be related to the model parameter of the responses.
I have tested the below on 0.79.1 and 0.81.0

from typing import Union

from fastapi import FastAPI, APIRouter
from fastapi.responses import FileResponse
from pydantic import BaseModel


class Item(BaseModel):
    id: str
    value: str


responses = {
    404: {"description": "Item not found"},
    302: {"description": "The item was moved"},
    403: {"description": "Not enough privileges"},
    "5XX": {"description": "Server errors", "model": Item},
}


app = FastAPI(responses=responses)
router = APIRouter()

@router.get(
    "/items/{item_id}",
    response_model=Item,
)
async def read_item(item_id: str, img: Union[bool, None] = None):
    if img:
        return FileResponse("image.png", media_type="image/png")
    else:
        return {"id": "foo", "value": "there goes my hero"}

app.include_router(router)