'FastAPI handling and redirecting 404

How can i redirect a request with FastAPI if there is a HTTPException?

In Flask we can achieve that like this:

@app.errorhandler(404)
def handle_404(e):
    if request.path.startswith('/api'):
        return render_template('my_api_404.html'), 404
    else:
        return redirect(url_for('index'))

Or in Django we can use django.shortcuts:

from django.shortcuts import redirect

def view_404(request, exception=None):
    return redirect('/')

How we can achieve that with FastAPI?

Solution 1:^[1]

I know it's too late but this is the shortest approach to handle 404 exceptions in your personal way.

Redirect

from fastapi.responses import RedirectResponse


@app.exception_handler(404)
async def custom_404_handler(_, __):
    return RedirectResponse("/")

Custom Jinja Template

from fastapi.templating import Jinja2Templates
from fastapi.staticfiles import StaticFiles

templates = Jinja2Templates(directory="templates")
app.mount("/static", StaticFiles(directory="static"), name="static")

@app.exception_handler(404)
async def custom_404_handler(request, __):
    return templates.TemplateResponse("404.html", {"request": request})

Serve HTML from file

@app.exception_handler(404)
async def custom_404_handler(_, __):
    return FileResponse('./path/to/404.html')

Serve HTML directly

from fastapi.responses import HTMLResponse

response_404 = """
<!DOCTYPE html>
<html lang="en">
<head>
    <title>Not Found</title>
</head>
<body>
    <p>The file you requested was not found.</p>
</body>
</html>
"""
    
@app.exception_handler(404)
async def custom_404_handler(_, __):
    return HTMLResponse(response_404)

Note: exception_handler decorator passes the current request and exception as arguments to the function. I've used _ and __ where the variables are unnecessary.

Solution 2:^[2]

I uses this method,

from fastapi.responses import RedirectResponse
from starlette.exceptions import HTTPException as StarletteHTTPException

app.mount("/static", StaticFiles(directory="static"), name="static")

templates = Jinja2Templates(directory="templates")

@app.exception_handler(StarletteHTTPException)
async def custom_http_exception_handler(request, exc):
    return templates.TemplateResponse("404.html", {"request": request})

Make sure you have static folder, for your static files and templates folder your html files.

Sources

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Source: Stack Overflow

Solution	Source
Solution 1	Dharman
Solution 2	Dharman

'FastAPI handling and redirecting 404

Solution 1:[1]

Solution 2:[2]

Sources

Related Questions

Solution 1:^[1]

Solution 2:^[2]