FastAPI installation and setup - Practice Problems & Coding Challenges

Challenge - 5 Problems

📝 Syntax

intermediate

Correct command to install FastAPI with Uvicorn

Which command correctly installs FastAPI along with Uvicorn for running the server?

A pip install fastapi; uvicorn install

B pip install fastapi-uvicorn

C pip install fastapi --with uvicorn

D pip install fastapi uvicorn

💡 Hint

Think about how Python packages are installed together using pip.

The correct way to install FastAPI and Uvicorn together is by listing both packages separated by a space in one pip install command.

❓ component_behavior

intermediate

Behavior of a minimal FastAPI app

What will be the output when you visit http://localhost:8000/ after running this FastAPI app code?

FastAPI

from fastapi import FastAPI
app = FastAPI()

@app.get('/')
async def read_root():
    return {"message": "Hello, FastAPI!"}

A {"message": "Hello, FastAPI!"}

B Hello, FastAPI!

C 404 Not Found error

D 500 Internal Server Error

💡 Hint

FastAPI returns JSON responses by default from dictionary returns.

The function returns a dictionary, so FastAPI converts it to JSON automatically. The browser will show the JSON string.

🔧 Debug

advanced

Identify the error when running FastAPI app

What error will occur if you run this code and try to start the server with uvicorn main:app --reload?

FastAPI

from fastapi import FastAPI
app = FastAPI()

@app.get('/')
def read_root():
    return "Hello"

A TypeError: FastAPI endpoint must return dict or Response, not str

B No error, server runs and returns plain text 'Hello'

C SyntaxError: missing async keyword

D RuntimeError: Uvicorn not installed

💡 Hint

FastAPI can return strings directly as plain text responses.

FastAPI allows returning strings directly, which it sends as plain text. No error occurs.

🧠 Conceptual

advanced

Purpose of Uvicorn in FastAPI setup

What is the main role of Uvicorn when used with FastAPI?

A It is a database driver required for FastAPI to connect to databases

B It is a frontend framework to build user interfaces for FastAPI apps

C It is an ASGI server that runs the FastAPI app and handles requests asynchronously

D It is a testing tool to check FastAPI app performance

💡 Hint

Think about what runs your app and listens for web requests.

Uvicorn is a lightweight ASGI server that runs FastAPI apps and handles asynchronous web requests.

❓ state_output

expert

Output after modifying FastAPI app with startup event

Given this FastAPI app code, what will be printed to the console when the server starts?

FastAPI

from fastapi import FastAPI
app = FastAPI()

@app.on_event("startup")
async def startup_event():
    print("Server is starting...")

@app.get('/')
async def read_root():
    return {"status": "running"}

A Server is starting...

B No output printed on startup

C Error: on_event decorator not found

D Server is starting...\nGET / 200 OK

💡 Hint

The startup event runs once when the server launches.

The @app.on_event("startup") decorator runs the function when the server starts, printing the message once.