Quichex

Quichex exposes the cloudflare/quiche QUIC implementation to Elixir via Rustler. The public API currently lives under Quichex.Native, providing direct access to connection/configuration/packet helpers. Most calls return {:ok, term} / {:error, reason} tuples, while config setters return the config reference and raise Quichex.Native.ConfigError on failure.

Capabilities

• Build QUIC client and server connections directly from Elixir, including TLS configuration and datagram support.
• Create HTTP/3 connections and exchange request/response headers and bodies.
• Build WebTransport CONNECT headers and send/receive WebTransport datagrams.
• Inspect negotiated transport parameters, runtime stats, connection IDs, and peer errors via strongly typed structs.
• Drive streams and datagrams using either in-VM helpers (see test/quichex/native/connection_test.exs) or real UDP sockets (see the :socket-based integration test).
• Capture and reuse TLS session blobs for fast resumption, and toggle keylog paths for debugging.

Example Workflow

alias Quichex.Native.TestHelpers

{_, client} = TestHelpers.create_connection()
{_, server} = TestHelpers.accept_connection()

:ok = TestHelpers.ok!(Quichex.Native.connection_stream_send(client, 0, "hi", true))

HTTP/3 Example

alias Quichex.H3

# assumes `conn` is an established QUIC connection
h3_config = H3.config_new()
h3_conn = H3.conn_new_with_transport(conn, h3_config)

stream_id =
  H3.send_request(conn, h3_conn, [
    {":method", "GET"},
    {":scheme", "https"},
    {":authority", "localhost"},
    {":path", "/"}
  ], true)

_ = H3.conn_poll(conn, h3_conn)

WebTransport Example

alias Quichex.WebTransport

# assumes `conn` + `h3_conn` are ready for HTTP/3
stream_id = WebTransport.connect(conn, h3_conn, "localhost", "/moq")
WebTransport.send_datagram(conn, stream_id, "ping")

Testing

All tests can be run with:

mix test

External HTTP/3 integration tests can be run with:

QUICHEX_INTEGRATION=1 mix test test/quichex/h3_integration_test.exs

The suite exercises:

• Unit coverage for metadata, datagram helpers, packet helpers, and error cases.
• Deterministic client/server simulations that exchange streams and datagrams.
• A :socket-based test that routes packets through real OS UDP sockets to catch wiring regressions.
• TLS session resumption, transport parameter validation, stats aggregation, and failure scenarios (invalid shutdown directions, zero-length datagram reads, post-close stream sends).

Refer to test/quichex/native/connection_test.exs for examples showing how to create configs, accept connections, and pump packets between peers entirely from Elixir.