websocket-extensions

A framework for negotiating and running WebSocket extensions, per RFC 6455 section 9. It gives a WebSocket driver the negotiation and pipeline machinery, and the extension algorithms themselves come from plugins.

The crate provides three things:

1. A parser and serializer for the Sec-WebSocket-Extensions header.
2. An Extensions container that registers plugins, builds client offers, activates server responses, builds server responses, detects RSV-bit conflicts, and validates frame RSV bits.
3. An ordered async pipeline that runs each message through every active session, preserves input order under out-of-order completion, and closes sessions after in-flight messages drain.

Install

[dependencies]
websocket-extensions = "0.1"

Roles

A driver holds one Extensions per socket.

A client advertises extensions with generate_offer, sends the offer, then calls activate with the server's response header.

A server calls generate_response with the client's offer header and sends the result back.

Both sides then transform messages with process_incoming_message and process_outgoing_message, and shut down with close.

Plugins

A plugin implements Extension. Its sessions implement ClientSession or ServerSession, which extend Session. The message type is generic, so a driver chooses its own frame representation.

Header parsing

use websocket_extensions::parser::{parse_header, serialize_params};

let offers = parse_header(Some("permessage-deflate; client_max_window_bits")).unwrap();
assert_eq!(offers[0].name, "permessage-deflate");

parse_header takes Option<&str>. None and an empty string both yield an empty offer list. A malformed header returns an error. The parser is linear, so an unterminated quoted string fails fast.

License

Licensed under the MIT license.