Crate yawc 

yawc

WebSocket (RFC 6455) with permessage-deflate compression (RFC 7692). Autobahn compliant. Supports WASM targets.

Features

• reqwest: WebSocket via reqwest HTTP client
• axum: WebSocket extractor for axum
• zlib: Advanced compression with window size control
• json: JSON serialization support

Runtime Support

yawc is built on tokio’s I/O traits but can work with other async runtimes through simple adapters. While the library uses tokio internally for its codec and I/O operations, you can integrate it with runtimes like smol, async-std, or others by implementing trait bridges between their I/O traits and tokio’s AsyncRead/AsyncWrite.

See the client_smol.rs example for a complete demonstration of using yawc with the smol runtime.

Client Example

use futures::{SinkExt, StreamExt};
use yawc::{WebSocket, frame::OpCode};

async fn connect() -> yawc::Result<()> {
    let mut ws = WebSocket::connect("wss://echo.websocket.org".parse()?).await?;

    while let Some(frame) = ws.next().await {
        match frame.opcode() {
            OpCode::Text | OpCode::Binary => ws.send(frame).await?,
            OpCode::Ping => {
                // Pong is sent automatically, but ping is still returned
                // so you can observe it if needed
            }
            _ => {}
        }
    }
    Ok(())
}

Protocol Handling

yawc automatically handles WebSocket control frames:

• Ping frames: Automatically responded to with pongs, but still returned to your application
• Pong frames: Passed through without special handling
• Close frames: Automatically acknowledged, then returned before closing the connection

Server Example

use http_body_util::Empty;
use futures::StreamExt;
use hyper::{Request, body::{Incoming, Bytes}, Response};
use yawc::WebSocket;

async fn upgrade(mut req: Request<Incoming>) -> yawc::Result<Response<Empty<Bytes>>> {
    let (response, fut) = WebSocket::upgrade(&mut req)?;

    tokio::spawn(async move {
        if let Ok(mut ws) = fut.await {
            while let Some(frame) = ws.next().await {
                // Process frames
            }
        }
    });

    Ok(response)
}

Modules

close

codecNon-WebAssembly

codec

frame

Frame

streamingNon-WebAssembly

Low-level streaming WebSocket layer for manual fragment control.

Structs

DeflateOptions

Configuration options for WebSocket message compression using the Deflate algorithm.

Fragmentation

Configuration for WebSocket message fragmentation.

IncomingUpgradeaxum

Represents an incoming WebSocket upgrade request that can be converted into a WebSocket connection.

Options

Configuration options for a WebSocket connection.

ReadHalf

The read half of a WebSocket connection, responsible for receiving and processing incoming messages.

UpgradeFut

Future that completes the WebSocket upgrade process on a server, returning a WebSocket stream.

WebSocketNon-WebAssembly

WebSocket stream for both clients and servers.

WebSocketBuilder

Builder for establishing WebSocket connections with customizable options.

WriteHalf

Write half of the WebSocket connection.

Enums

HttpStreamNon-WebAssembly

An enum representing the underlying WebSocket stream types based on the enabled features.

MaybeTlsStream

A stream that might be protected with TLS.

RoleNon-WebAssembly

The role the WebSocket stream is taking.

WebSocketError

Errors that can occur during WebSocket operations.

Constants

MAX_PAYLOAD_READNon-WebAssembly

The maximum allowed payload size for reading, set to 1 MiB.

MAX_READ_BUFFERNon-WebAssembly

The maximum allowed read buffer size, set to 2 MiB.

Type Aliases

CompressionLevel

Type alias for the compression level used in WebSocket compression settings.

HttpRequest

Type alias for HTTP requests used in WebSocket connection handling.

HttpRequestBuilder

Type alias for HTTP request builders used in WebSocket client connection setup.

HttpResponseNon-WebAssembly

Type alias for HTTP responses used during WebSocket upgrade.

HttpWebSocketNon-WebAssembly

Type alias for server-side WebSocket connections from HTTP upgrades or when using reqwest.

Result

Result type for WebSocket operations.

TcpWebSocketNon-WebAssembly

Type alias for WebSocket connections established via connect.

UpgradeResultNon-WebAssembly

The result type returned by WebSocket upgrade operations.