Query parameter validation in FastAPI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a query parameter named 'q' as optional.

FastAPI

from fastapi import FastAPI
from typing import *

app = FastAPI()

@app.get("/items/")
async def read_items(q: [1] = None):
    return {"q": q}

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

AList[str]

BOptional[str]

Cint

Dstr

Attempts:

3 left

💡 Hint

Common Mistakes

Using just 'str' makes the parameter required.

Using 'int' when the parameter should be a string.

Using Optional[str] allows the query parameter to be optional (can be None or a string).

2fill in blank

medium

Complete the code to set a minimum length of 3 for the query parameter 'q'.

FastAPI

from fastapi import FastAPI, Query

app = FastAPI()

@app.get("/items/")
async def read_items(q: str = Query([1], min_length=3)):
    return {"q": q}

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

A''

BNone

C...

D""

Attempts:

3 left

💡 Hint

Common Mistakes

Using None makes the parameter optional.

Using empty strings does not enforce required parameter.

The ... (Ellipsis) tells FastAPI that this query parameter is required.

3fill in blank

hard

Fix the error in the code to correctly validate that 'q' is an integer query parameter with a maximum value of 10.

FastAPI

from fastapi import FastAPI, Query

app = FastAPI()

@app.get("/items/")
async def read_items(q: int = Query([1], le=10)):
    return {"q": q}

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

A0

B10

CNone

D...

Attempts:

3 left

💡 Hint

Common Mistakes

Using None makes the parameter optional.

Using a default value disables required validation.

Using ... makes the parameter required and applies the validation with le=10 (less or equal to 10).

4fill in blank

hard

Fill both blanks to declare a query parameter 'q' that is optional and has a regex pattern to allow only letters.

FastAPI

from fastapi import FastAPI, Query

app = FastAPI()

@app.get("/items/")
async def read_items(q: str = Query([1], regex=[2])):
    return {"q": q}

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

ANone

B"^[a-zA-Z]+$"

C"^\d+$"

D...

Attempts:

3 left

💡 Hint

Common Mistakes

Using Ellipsis makes the parameter required.

Using wrong regex pattern allows digits.

Setting the default to None makes the parameter optional. The regex "^[a-zA-Z]+$" allows only letters.

5fill in blank

hard

Fill all three blanks to declare a query parameter 'q' that is required, has a minimum length of 2, and a maximum length of 5.

FastAPI

from fastapi import FastAPI, Query

app = FastAPI()

@app.get("/items/")
async def read_items(q: str = Query([1], min_length=[2], max_length=[3])):
    return {"q": q}

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

ANone

B2

C5

D...

Attempts:

3 left

💡 Hint

Common Mistakes

Using None makes the parameter optional.

Swapping min_length and max_length values.

The Ellipsis ... marks the parameter as required. min_length=2 and max_length=5 set length limits.