Validation error responses in FastAPI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the class used for validation errors in FastAPI.

FastAPI

from fastapi.exceptions import [1]

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

ARequestValidationError

BHTTPException

CValidationError

DDepends

Attempts:

3 left

💡 Hint

Common Mistakes

Using HTTPException instead of RequestValidationError

Using ValidationError from Pydantic directly

The RequestValidationError class is used by FastAPI to represent validation errors in requests.

2fill in blank

medium

Complete the code to create a FastAPI exception handler for validation errors.

FastAPI

@app.exception_handler([1])
async def validation_exception_handler(request, exc):
    return JSONResponse(status_code=422, content={"detail": exc.errors()})

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

AHTTPException

BRequestValidationError

CValidationError

DValueError

Attempts:

3 left

💡 Hint

Common Mistakes

Using HTTPException instead of RequestValidationError

Using ValidationError from Pydantic

The @app.exception_handler decorator needs the RequestValidationError to catch validation errors.

3fill in blank

hard

Fix the error in the handler to return the validation errors correctly as JSON.

FastAPI

from fastapi.responses import JSONResponse

@app.exception_handler(RequestValidationError)
async def validation_exception_handler(request, exc):
    return JSONResponse(status_code=422, content=[1])

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

A{"errors": exc.errors()}

B{"detail": exc.json()}

C{"detail": exc.errors()}

Dexc.errors()

Attempts:

3 left

💡 Hint

Common Mistakes

Returning exc.errors() directly without wrapping in a dict

Using exc.json() which returns a string, not a dict

The response content must be a dictionary with a detail key holding the list of errors.

4fill in blank

hard

Fill both blanks to import and use the correct JSON response class and error class for validation errors.

FastAPI

from fastapi.responses import [1]
from fastapi.exceptions import [2]

@app.exception_handler(RequestValidationError)
async def validation_exception_handler(request, exc):
    return JSONResponse(status_code=422, content={"detail": exc.errors()})

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

AJSONResponse

BRequestValidationError

CHTTPException

DPlainTextResponse

Attempts:

3 left

💡 Hint

Common Mistakes

Using PlainTextResponse instead of JSONResponse

Using HTTPException instead of RequestValidationError

Use JSONResponse to send JSON data and RequestValidationError to catch validation errors.

5fill in blank

hard

Fill all three blanks to define a custom validation error handler that logs the error, returns JSON with status 422, and uses the correct imports.

FastAPI

from fastapi.exceptions import [1]
from fastapi.responses import [2]
import logging

logger = logging.getLogger(__name__)

@app.exception_handler([3])
async def validation_exception_handler(request, exc):
    logger.error(f"Validation error: {exc}")
    return JSONResponse(status_code=422, content={"detail": exc.errors()})

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

ARequestValidationError

BJSONResponse

DHTTPException

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing HTTPException with validation error handling

Forgetting to import JSONResponse

Import RequestValidationError from fastapi.exceptions, JSONResponse from fastapi.responses, and use RequestValidationError in the handler decorator.