Recently-released RFC 6585 introduces three new client-error status codes: 428, 429, and 431. I have added HTTPException subclasses "PreconditionRequired", "TooManyRequests", and "RequestHeaderFieldsTooLarge" to represent these status codes. (The RFC also adds a server-error status code, 511, but that is for proxies rather than origin servers so I don't include it.)
Adding HTTPException subclasses for HTTP statuses 428, 429, and 431,
which were recently added in RFC 6585.
Great addition, 429 is really useful. Someone merge it in pls :)
@mitsuhiko, what do you think about adding these additional status codes?