Crate engineioxide

Engineioxide does the heavy lifting for socketioxide, a socket.io server implementation in Rust which integrates with the tower stack.

You can still use engineioxide as a standalone crate to talk with an engine.io client.

Supported Protocols

You can enable support for other engine.io protocol implementations through feature flags. The latest protocol version (v4) is enabled by default.

To add support for the v3 protocol version, adjust your dependency configuration accordingly:

[dependencies]
# Enables the `v3` protocol (`v4` is always enabled, as it's the default).
engineioxide = { version = "0.3.0", features = ["v3"] }

Feature flags :

• v3: Enable the engine.io v3 protocol
• tracing: Enable tracing logs with the tracing crate

Basic example with axum :

use engineioxide::layer::EngineIoLayer;
use engineioxide::handler::EngineIoHandler;
use engineioxide::{Socket, DisconnectReason};
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::{Arc, Mutex};
use axum::routing::get;
// Global state, with axum it must be clonable
#[derive(Debug, Default, Clone)]
struct MyHandler {
    user_cnt: Arc<AtomicUsize>,
}

// Socket state
#[derive(Debug, Default)]
struct SocketState {
    id: Mutex<String>,
}

impl EngineIoHandler for MyHandler {
    type Data = SocketState;

    fn on_connect(&self, socket: Arc<Socket<SocketState>>) { 
        let cnt = self.user_cnt.fetch_add(1, Ordering::Relaxed) + 1;
        socket.emit(cnt.to_string()).ok();
    }
    fn on_disconnect(&self, socket: Arc<Socket<SocketState>>, reason: DisconnectReason) { 
        let cnt = self.user_cnt.fetch_sub(1, Ordering::Relaxed) - 1;
        socket.emit(cnt.to_string()).ok();
    }
    fn on_message(&self, msg: String, socket: Arc<Socket<SocketState>>) { 
        *socket.data.id.lock().unwrap() = msg; // bind a provided user id to a socket
    }
    fn on_binary(&self, data: Vec<u8>, socket: Arc<Socket<SocketState>>) { }
}

// Create a new engineio layer
let layer = EngineIoLayer::new(MyHandler::default());

let app = axum::Router::<()>::new()
    .route("/", get(|| async { "Hello, World!" }))
    .layer(layer);

// Spawn the axum server

Re-exports

• pub use service::ProtocolVersion;
• pub use service::TransportType;
• pub use socket::DisconnectReason;
• pub use socket::Socket;

Modules

• config
  Configuration for the engine.io engine & transports
• handler
  An EngineIoHandler to get event calls for any engine.io socket
• layer
  A tower [Layer] for engine.io so it can be used as a middleware with frameworks supporting layers
• service
  A tower Service for engine.io so it can be used with frameworks supporting tower services
• sid
  Socket id type and generator
• socket
  A Socket represents a client connection to the server