Exception Handlers

HTTP exceptions

JetWeb represents HTTP errors using HTTPException, which is both an Exception and a valid Response. When you raise HTTPException, the client receives the corresponding response:

from jetweb import HTTPException, JetWeb, Request

app = JetWeb()


@app.get("/hello")
def hello(request: Request) -> None:
    raise HTTPException(status=403, content="Not authenticated")

The framework may also raise HTTPException automatically in these cases:

• HTTPException(status=404) — no route matched the request endpoint.
• HTTPException(status=405) — a route matched, but the HTTP method is not allowed.
• HTTPException(status=500) — any other unhandled exception. When JetWeb(debug=True) is enabled, the response contains the full traceback.

Handling HTTPException

You can register handlers for particular HTTP statuses:

from jetweb import HTTPException, JetWeb

app = JetWeb()


@app.exception_handler(404)
def not_found(exception: HTTPException) -> dict:
    return {"detail": "Route was not found"}

⚠️ Warning: Exception handlers mustn't raise any exception because it won't be caught.