Global exception middleware in FastAPI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the correct FastAPI class.

FastAPI

from fastapi import [1]
app = FastAPI()

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ADepends

BRequest

CResponse

DFastAPI

Attempts:

3 left

💡 Hint

Common Mistakes

Importing Request or Response instead of FastAPI.

Using lowercase fastapi instead of FastAPI.

The FastAPI class is imported from fastapi to create the app instance.

2fill in blank

medium

Complete the code to import the ExceptionMiddleware from Starlette.

FastAPI

from starlette.middleware.errors import [1]

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AExceptionMiddleware

BBaseHTTPMiddleware

CMiddleware

DErrorMiddleware

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing ExceptionMiddleware with BaseHTTPMiddleware.

Using Middleware or ErrorMiddleware which do not exist in this context.

ExceptionMiddleware is the middleware class used to catch global exceptions.

3fill in blank

hard

Fix the error in the middleware setup by completing the missing argument.

FastAPI

app.add_middleware(ExceptionMiddleware, app=[1], debug=False)

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Arequest

Bself

Capp

Dmiddleware

Attempts:

3 left

💡 Hint

Common Mistakes

Passing 'request' or 'self' which are not the app instance.

Omitting the app argument entirely.

The ExceptionMiddleware requires the app instance passed as the 'app' argument.

4fill in blank

hard

Fill both blanks to define a global exception handler function that returns JSON response.

FastAPI

from fastapi.responses import JSONResponse

@app.exception_handler([1])
async def global_exception_handler(request, exc):
    return JSONResponse(status_code=500, content={"detail": [2])

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AException

B"An error occurred"

Cexc.detail

D"Internal Server Error"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a specific exception class instead of Exception.

Returning exc.detail which may not exist.

The handler catches all Exceptions and returns a JSON with a simple error message.

5fill in blank

hard

Fill all three blanks to create a middleware that logs exceptions and re-raises them.

FastAPI

from starlette.middleware.base import BaseHTTPMiddleware

class LoggingExceptionMiddleware(BaseHTTPMiddleware):
    async def dispatch(self, request, call_next):
        try:
            response = await call_next(request)
            return response
        except [1] as exc:
            print(f"Error: [2]")
            raise [3]

Drag options to blanks, or click blank then click option'

AException

Bexc

DRuntimeError

Attempts:

3 left

💡 Hint

Common Mistakes

Catching RuntimeError instead of all Exceptions.

Printing wrong variable or re-raising a different exception.

The middleware catches all exceptions, logs the exception object, and re-raises it.