Fastapi: Adding response parameter to endpoint function breaks Swagger UI

Created on 23 Jul 2020 · 3Comments · Source: tiangolo/fastapi

First check

[x] I added a very descriptive title to this issue.
[x] I used the GitHub search to find a similar issue and didn't find it.
[x] I searched the FastAPI documentation, with the integrated search.
[x] I already searched in Google "How to X in FastAPI" and didn't find any information.
[x] I already read and followed all the tutorial in the docs and didn't find an answer.
[ ] I already checked if it is not related to FastAPI but to Pydantic. (not sure how to determine this)
[ ] I already checked if it is not related to FastAPI but to Swagger UI. (not sure how to determine this)
[ ] I already checked if it is not related to FastAPI but to ReDoc. (not sure how to determine this)
[x] After submitting this, I commit to one of:
- Read open issues with questions until I find 2 issues where I can help someone and add a comment to help there.
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- Implement a Pull Request for a confirmed bug.

Problem

Following tutorial here: https://fastapi.tiangolo.com/advanced/response-change-status-code/

Adding response as a parameter to an endpoint completely breaks swagger ui, server throws

...
  File "/Users/atartanian/Development/carmera/carmera_take_home/.venv/lib/python3.8/site-packages/fastapi/openapi/utils.py", line 101, in get_openapi_operation_parameters
    "schema": field_schema(
  File "pydantic/schema.py", line 177, in pydantic.schema.field_schema
  File "pydantic/schema.py", line 712, in pydantic.schema.encode_default
  File "pydantic/json.py", line 62, in pydantic.json.pydantic_encoder
TypeError: Object of type 'type' is not JSON serializable

minimally reproducible with the following code:

from fastapi import FastAPI, Response

app = FastAPI()

@app.get("/test", status_code=200)
async def test(
    response=Response
):
    return {"message": "tada"}

Environment

OS: macOS
FastAPI version: 0.60.1
Python version 3.8.2

Additional context

Screen Shot 2020-07-23 at 5 21 55 PM

question

Source

atartanian

Most helpful comment

Fix: response=Response -> response: Response.

from fastapi import FastAPI, Response

app = FastAPI()

@app.get("/test", status_code=200)
async def test(
    response: Response
):
    return {"message": "tada"}

Kludex on 23 Jul 2020

👍2

All 3 comments

Fix: response=Response -> response: Response.

from fastapi import FastAPI, Response

app = FastAPI()

@app.get("/test", status_code=200)
async def test(
    response: Response
):
    return {"message": "tada"}

Kludex on 23 Jul 2020

👍2