How to change the response type of /openapi.json

[captaincoordinates]

There appears to be an active discussion around the preferred MIME type for OpenAPI documentation. FastAPI provides /openapi.json with the application/json MIME type.

I am attempting to use FastAPI to implement the OGC API - Features - Part 1: Core 1.0 spec which requires OpenAPI documentation be provided with MIME type application/vnd.oai.openapi+json;version=3.0 (see here).

Is it possible to change the response type of /openapi.json within FastAPI? Looking through the documentation and searching around the internet I don't see any way to do this.

[waynerv]

Thanks for the flexiable of FastAPI, this is pretty much easy. You just need create a custom Response class, and ues it as response_class in route:

from typing import List, Optional

from fastapi import FastAPI
from pydantic import BaseModel
from starlette.responses import JSONResponse

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Optional[str] = None
    price: float
    tax: Optional[float] = None
    tags: List[str] = []


class VndResponse(JSONResponse):
    media_type = 'application/vnd.oai.openapi+json;version=3.0'


@app.post("/items/", response_model=Item, response_class=VndResponse)
async def create_item(item: Item):
    return item

[juntatalor]

@captaincoordinates Hi!
The openapi handler is declared inside the FastAPI.setup() as an inner function that returns JSONresponse. I'm afraid that the only one way is to subclass FastAPI and write your own setup implementation.

[captaincoordinates]

@juntatalor thanks for the info. Anyone else who's looking for this I found the described method here.

[tiangolo]

Thanks for the help here everyone! 👏 🙇

Thanks for reporting back and closing the issue @captaincoordinates 👍

Sorry for the long delay! 🙈 I wanted to personally address each issue/PR and they piled up through time, but now I'm checking each one in order.