RuntimeError: no validator found for <class 'starlette.responses.Response'>

[nrshapiro]

Describe the bug
This example from the documentation does not work

from fastapi import FastAPI
from starlette.responses import Response

app = FastAPI()


@app.get("/headers-and-object/")
def get_headers(response: Response):
    response.headers["X-Cat-Dog"] = "alone in the world"
    return {"message": "Hello World"}

To Reproduce
Steps to reproduce the behavior:

1. Try the example under "Use a Response parameter"
2. See error

Expected behavior
It should run and add to the response. It gives an error instead:
builtins.RuntimeError: no validator found for <class 'starlette.responses.Response'>

Environment:

• OS: Windows

• FastAPI Version [e.g. 0.3.0], get it with: 27.2

• Python version, get it with: 3.7.3

Additional context
There's also no validator for JSONResponse, but that's not needed because it's not required to be a parameter of the function.

[jekirl]

Looks to be working with 0.31.0....Was that example in the docs for 0.27.2?

See below:

from starlette.responses import Response
from starlette.testclient import TestClient

app = FastAPI()


@app.get("/headers-and-object/")
def get_headers(response: Response):
    response.headers["X-Cat-Dog"] = "alone in the world"
    return {"message": "Hello World"}

def test_bug():
    client = TestClient(app)
    r = client.get("/headers-and-object/")
    assert r.headers["X-Cat-Dog"] == "alone in the world"
    assert r.json() == {"message": "Hello World"}```

[nrshapiro]

Yes, it was fixed in a later version than I had--which Tiangolo pointed out in the gitter chat. I hadn't installed it that long ago and it never occured to me that the version could be out-of-date. And I was using the online docs, so probably were in a later version anyway. All better. :) Regards--Neil

…

------ Original Message ------ From: "James Kaplan" <[email protected]> To: "tiangolo/fastapi" <[email protected]> Cc: "Neil Shapiro" <[email protected]>; "Author" <[email protected]>

Sent: 7/4/2019 10:50:38 AM Subject: Re: [tiangolo/fastapi] [BUG] (#358) Looks to be working with 0.31.0....Was that example in the docs for 0.27.2? See below: from starlette.responses import Response from starlette.testclient import TestClient app = FastAPI() @app.get("/headers-and-object/") def get_headers(response: Response): response.headers["X-Cat-Dog"] = "alone in the world" return {"message": "Hello World"} def test_bug(): client = TestClient(app) r = client.get("/headers-and-object/") assert r.headers["X-Cat-Dog"] == "alone in the world" assert r.json() == {"message": "Hello World"}``` — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#358>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABE5BMVF5TXWCVC4PJ3XLJLP5YE35ANCNFSM4H4V3AUQ>.

[jonathanunderwood]

I think this can be closed, right?

[tiangolo]

Thanks for the help @jekirl and @jonathanunderwood ! 🍰

I'm glad you solved your problem @nrshapiro , I'll close this now. 🎉