Run RequestValidationError before middlewares

[edanbenavi]

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Example Code

from fastapi import FastAPI
from fastapi.exceptions import RequestValidationError
app = FastAPI()

def middleware_example(): 
    pass

async def request_input_validator(request: Request, exc):
    return Exception("Bad Input")


app.add_pre_request_middleware(middleware_example)
app.add_exception_middlewares(RequestValidationError, request_input_validator)

Description

when running this code the "middleware_example" function running before the "request_input_validator"

i want to find an option to use RequestValidationError before the middleware

The logic behind it : first check if is the body is according to the pydantic schema
if the check pass -> move to the middleware
else : raise error

Operating System

macOS

Operating System Details

No response

FastAPI Version

lastest

Python Version

3.11

Additional Context

No response

[thesubuck]

@edanbenavi , You cannot change the order of execution . Middleware runs first before exception handlers (including RequestValidationError). Even you define a custom router and a middleware, the control goes through the app like this :

middleware -> CustomRouter -> Route

Since you haven't mentioned a specific middleware, I don't know your use-case to suggest further.