Servers field in `openapi.json` not shown even after set `root_path`

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• I already checked if it is not related to FastAPI but to Swagger UI.
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Example Code

from fastapi import FastAPI
from fastapi.exceptions import HTTPException, RequestValidationError
from fastapi.responses import ORJSONResponse, RedirectResponse

app = FastAPI(
    root_path='/api/v1'
)

Description

I’m trying to run my API behind proxy. The proxy I’m used is apache2. The API is running smoothly (I’m running the API using gunicorn). But, when I tried to open the swagger docs using <domain>/api/v1/docs and test one of the function, it’s not working properly. And I realize that servers parameter in openapi.json is not shown. It should be like this:

{
    "openapi": "3.0.2",
    "servers": [
        {"url": "/api/v1"}
    ],
    ...
}

But, what is shown is like this

{
    "openapi": "3.0.2",
    ...
}

I think this is why when I test the API from the swagger docs, the test is not working properly.

Operating System

Linux

Operating System Details

No response

FastAPI Version

0.68.1

Python Version

3.9.6

Additional Context

No response

[fahadh4ilyas]

Ah, I get it now. This is because custom_openapi. I have to add servers=app.servers inside get_openapi.

[fahadh4ilyas]

Dumbing it down works. I only use this script as main

from fastapi import FastAPI

app = FastAPI(
    root_path='/api/v1',
    servers=[{'url': '/api/v1'}]
)

@app.get('/')
async def hello():

    return {'result': 'Hello, World!'}

My real API using this parameter for app:

• title
• description
• openapi_tags value as list of dictionary
• default_response_class value as ORJSONResponse
• responses to set model for 504 status code

I also add FastAPILimiter. and custom the openapi using this

app.openapi = custom_openapi(app)

where custom_openapi is this

def custom_openapi(app: FastAPI):
    def wrapper():
        if app.openapi_schema:
            return app.openapi_schema
        openapi_schema = get_openapi(
            title=app.title,
            description=app.description,
            version=app.version,
            routes=app.routes,
            tags=app.openapi_tags
        )

        http_methods = ["post", "get", "put", "delete"]
        # look for the error 422 and removes it
        for method in openapi_schema["paths"]:
            for m in http_methods:
                try:
                    del openapi_schema["paths"][method][m]["responses"]["422"]
                except KeyError:
                    pass
                # try:
                #     if openapi_schema["paths"][method][m]["responses"]["200"]['description'] == 'Successful Response':
                #         del openapi_schema["paths"][method][m]["responses"]["200"]
                # except KeyError:
                #     pass
        for schema in list(openapi_schema["components"]["schemas"]):
            if schema in ["HTTPValidationError", "ValidationError"]:
                del openapi_schema["components"]["schemas"][schema]

        app.openapi_schema = openapi_schema
        return app.openapi_schema
    return wrapper