WebSocket authentication in FastAPI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to accept a WebSocket connection in FastAPI.

FastAPI

from fastapi import FastAPI, WebSocket
app = FastAPI()

@app.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket):
    await websocket.[1]()
    await websocket.send_text("Connected")

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

Aopen

Baccept

Cconnect

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using websocket.connect() instead of websocket.accept()

Trying to send data before accepting the connection

You must call websocket.accept() to accept the WebSocket connection before sending or receiving data.

2fill in blank

medium

Complete the code to receive a JSON message from the WebSocket.

FastAPI

data = await websocket.[1]()

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

Areceive_text

Breceive_data

Creceive_bytes

Dreceive_json

Attempts:

3 left

💡 Hint

Common Mistakes

Using receive_text() and then parsing JSON manually

Using receive_bytes() which returns raw bytes

To receive JSON data, use websocket.receive_json() which parses the incoming message as JSON.

3fill in blank

hard

Fix the error in the code to check a token from query parameters during WebSocket connection.

FastAPI

token = websocket.query_params.get("token")
if not token or token != "secret":
    await websocket.[1](1008)
    return

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

Areject

Bdisconnect

Cclose

Dabort

Attempts:

3 left

💡 Hint

Common Mistakes

Using disconnect() which is not a WebSocket method

Using reject() which does not exist

To close a WebSocket connection with a code, use websocket.close(code).

4fill in blank

hard

Fill both blanks to send a welcome message including the username after authentication.

FastAPI

username = websocket.query_params.get("username")
await websocket.[1]()
await websocket.[2](f"Welcome, {username}!")

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

Aaccept

Bsend_text

Csend_json

Dconnect

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to send before accepting

Using send_json() with a string instead of a dict

First accept the connection, then send a text message with send_text().

5fill in blank

hard

Fill all three blanks to implement a WebSocket endpoint that authenticates by token, accepts connection, and echoes received messages.

FastAPI

from fastapi import FastAPI, WebSocket
app = FastAPI()

@app.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket):
    token = websocket.query_params.get("token")
    if token != [1]:
        await websocket.[2](1008)
        return
    await websocket.[3]()
    while True:
        data = await websocket.receive_text()
        await websocket.send_text(f"Echo: {data}")

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

A"secret"

Bclose

Caccept

D"token"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong token string

Not closing connection on invalid token

Not accepting connection before receiving

Check token against "secret", close connection if invalid, accept connection if valid.