Error handling

HTTP operations raise HTTPError, which carries kind, message, and optional method, url, and status_code context. Not every error populates every field.

import req


def main() raises:
    try:
        var response = req.get("https://example.com")
        response.raise_for_status()
    except error:
        if error.kind == req.ErrorKind.HTTPStatusError:
            print(error.status_code.value())
        else:
            print(error.kind, error.message)

HTTP 4xx/5xx is a normal response until raise_for_status() is called. Transport failures raise during sending or body consumption. A successful header response does not guarantee that a streamed body can be read completely.

Kinds	Meaning
InvalidURL, InvalidRequest	Invalid URL, headers, body, timeout, or configuration.
ConnectError, ReadError, WriteError	Transport failure in the corresponding phase.
ConnectTimeout, ReadTimeout, WriteTimeout	Phase timeout.
TLSError, ProtocolError	TLS verification/handshake or HTTP protocol failure.
TooManyRedirects, UnsafeRedirect	Redirect limit or HTTPS downgrade.
HTTPStatusError	Explicitly raised HTTP 4xx/5xx.
DecodeError, JSONDecodeError	Text/JSON decoding or invalid typed JSON access.
ClientClosed, StreamClosed	Operation on a closed client or stream.
StreamNotRead, StreamConsumed	Whole-body access before buffering or after chunk consumption.

Req does not automatically retry requests. If your application retries, consider whether the operation and request body can safely be sent again.

API details

HTTPError / ErrorKind