FastAPI and Frontend Integration: Implementing User Authentication

Frontend
1

Hey everyone! I’m new to frontend development and I’m struggling with user authentication. I’ve got a FastAPI backend with JWT security all set up and working for my API endpoints. But now I’m adding a frontend and I’m not sure how to restrict access to only users with valid tokens.

Here’s what I’ve got for my frontend route:

@app.get('/dashboard')
async def show_dashboard(request: Request, max_items: int = 20):
    user_data = await DB.users.find().limit(max_items).to_list(max_items)
    user_data = [format_user_info(user) for user in user_data]
    return templates.TemplateResponse('dashboard.html', {'request': request, 'users': user_data})

I know I need to check for a valid token before showing this page, but I’m lost on how to implement it. Any tips on securing frontend routes in FastAPI? Thanks!

2

hey nova73, i’ve been there! For frontend auth, u could try using session middleware. It’s pretty straightforward:

from starlette.middleware.sessions import SessionMiddleware

app.add_middleware(SessionMiddleware, secret_key='your-secret-key')

then check session in ur route. jus an idea, lmk if u need more help!

3

To secure your frontend routes in FastAPI, you’ll need to implement a dependency that checks for a valid JWT token. Here’s how you can approach this:

First, create a dependency function that verifies the token:

from fastapi import Depends, HTTPException
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials

async def verify_token(credentials: HTTPAuthorizationCredentials = Depends(HTTPBearer())):
    token = credentials.credentials
    if not your_token_validation_function(token):
        raise HTTPException(status_code=401, detail='Invalid token')
    return token

Then, use this dependency in your route:

@app.get('/dashboard')
async def show_dashboard(request: Request, token: str = Depends(verify_token), max_items: int = 20):
    # Your existing code here

This way, the route will only be accessible if a valid token is provided. Remember to handle token storage and transmission securely on the frontend, typically using secure HTTP-only cookies or local storage with HTTPS.

4

Ooh, authentication can be tricky! have you considered using a middleware approach? it could intercept requests before they hit your routes and check for valid tokens. Maybe something like:

@app.middleware("http")
async def auth_middleware(request, call_next):
    # Check token logic here

what do you think? How are you handling token storage on the frontend?