# caprid_relay.quic

> Python API reference for caprid_relay.quic: The native QUIC transport on aioquic.

URL: https://www.caprid.com/docs/reference/python/caprid_relay-quic/

From the `caprid-relay` package: `import caprid_relay.quic`

Native QUIC on aioquic: MOQT straight on a QUIC connection, with no HTTP/3 or WebTransport (ADR 0004).

The dialing end of the framing `@caprid/relay-quic` speaks for Node: the connection offers the MOQT
protocol identifiers as its ALPN list, and the core sends the endpoint's path (with the token) and
authority in SETUP instead of a CONNECT request (`spec/transport-adapter.md` TA-1 to TA-6). It is
the default transport of `connect_relay_publisher` and `connect_relay_subscriber`.

The Python SDK's only dialing end: the package carries no HTTP/3. Its modules follow the layers of the
connection: `_errors` (the transport layer's own exception), `_streams` (the send and receive halves of
a stream, and the link they need from their session), `_protocol` (the aioquic connection protocol with
the QUIC-level workarounds: the dropped-FIN retry, resets served first, the keepalive, the ICMP refusal
reports), `_session` (the halves' link, settlement and the drain before close) and `_client` (the
dial, ALPN selection and the application close). Three modules hold what is aioquic's or the socket's
rather than MOQT's: `_aioquic` names every private member the adapter reaches into, `_fin_retry` is
the dropped-FIN workaround (#47), deletable as a unit, and `_udp` binds the socket and hears a refused
port during the handshake (#163). The test suite builds its accepting ends, a WebTransport one included,
on the same protocol and session.

## Functions

### connect_quic

```python
def connect_quic(
    url: str,
    protocols: Sequence[str] = (),
    *,
    configuration: QuicConfiguration | None = None,
) -> ConnectingTransport
```

Start a native QUIC session to `url`'s host and port, offering `protocols` as the ALPN list.

Returns immediately; `ready` completes once the handshake negotiated one of `protocols`.
Only the host and port are read from `url`: the connection sends the path and the token in
SETUP. Pass a `QuicConfiguration` to control TLS verification (`cafile`/`cadata`/
`verify_mode`) or QUIC parameters; ALPN and the client role are set regardless.

<small>[Source](https://github.com/caprids/relay-sdks/blob/main/python/packages/caprid-relay/src/caprid_relay/quic/_client.py#L321)</small>