Custom request validation 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 = [1]()

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AFastAPI

BRequest

CResponse

DDepends

Attempts:

3 left

💡 Hint

Common Mistakes

Importing Request or Response instead of FastAPI

Forgetting to instantiate the app

The FastAPI class is used to create the app instance.

2fill in blank

medium

Complete the code to define a Pydantic model for request validation.

FastAPI

from pydantic import BaseModel

class User(BaseModel):
    name: [1]
    age: int

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Aint

Bbool

Cfloat

Dstr

Attempts:

3 left

💡 Hint

Common Mistakes

Using int for name field

Using bool or float for name

The name field should be a string, so use str.

3fill in blank

hard

Fix the error in the route to accept the User model as request body.

FastAPI

@app.post('/users')
async def create_user(user: [1]):
    return {'name': user.name, 'age': user.age}

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Adict

BUser

Cstr

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using dict instead of User

Using primitive types like str or int

The route parameter should be the Pydantic model User to validate the request body.

4fill in blank

hard

Fill both blanks to add a custom validator that checks age is positive.

FastAPI

from pydantic import BaseModel, field_validator

class User(BaseModel):
    name: str
    age: int

    @field_validator('[1]')
    def check_age(cls, value):
        if value [2] 0:
            raise ValueError('Age must be positive')
        return value

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

Aage

B>

C<=

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong field name in the validator

Using the wrong comparison operator

The validator targets the 'age' field and raises an error if the value is less than or equal to 0.

5fill in blank

hard

Fill all three blanks to create a route that validates a User and returns a greeting.

FastAPI

@app.post('/greet')
async def greet_user(user: [1]):
    return {'message': f'Hello, [2]! You are [3] years old.'}

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

AUser

B{user.name}

C{user.age}

Ddict

Attempts:

3 left

💡 Hint

Common Mistakes

Using dict instead of User for the parameter

Using wrong variable names in the message

The route accepts a User model, then uses user.name and user.age to create the greeting message.