hydrogen

Documentation

hydrogen is a non-blocking TCP socket lib built atop epoll with performance, concurrency, and scalability as its main priorities. It takes care of the tedious connection and I/O marshaling across threads, and leaves the specifics of I/O reading and writing up the consumer, through trait implementations.

Example Usage

extern crate hydrogen;
extern crate simple_stream as ss;

use hydrogen;
use hydrogen::{Stream as HydrogenStream, HydrogenSocket};
use ss::frame::Frame;
use ss::frame::simple::{SimpleFrame, SimpleFrameBuilder};
use ss::{Socket, Plain, NonBlocking, SocketOptions};



// Hydrogen requires a type that implements `hydrogen::Stream`.
// We'll implement it atop the `simple-stream` crate.
#[derive(Clone)]
pub struct Stream {
    inner: Plain<Socket, SimpleFrameBuilder>
}

impl HydrogenStream for Stream {    
    // This method is called when epoll reports data is available for reading.
    fn recv(&mut self) -> Result<Vec<Vec<u8>>, Error> {
        match self.inner.nb_recv() {
            Ok(frame_vec) => {
                let mut ret_buf = Vec::<Vec<u8>>::with_capacity(frame_vec.len());
                for frame in frame_vec.iter() {
                    ret_buf.push(frame.payload());
                }
                Ok(ret_buf)
            }
            Err(e) => Err(e)
        }
    }

    // This method is called when a previous attempt to write has returned `ErrorKind::WouldBlock`
    // and epoll has reported that the socket is now writable.
    fn send(&mut self, buf: &[u8]) -> Result<(), Error> {
        let frame = SimpleFrame::new(buf);
        self.inner.nb_send(&frame)
    }

    // This method is called when connection has been reported as reset by epoll, or when any
    // `std::io::Error` has been returned.
    fn shutdown(&mut self) -> Result<(), Error> {
        self.inner.shutdown()
    }
}
impl AsRawFd for Stream {
    fn as_raw_fd(&self) -> RawFd { self.inner.as_raw_fd() }
}


// The following will be our server that handles all reported events
struct Server;
impl hydrogen::Handler for Server {
    fn on_server_created(&mut self, fd: RawFd) {
        // Do any secific flag/option setting on the underlying listening fd.
        // This will be the fd that accepts all incoming connections.
    }

    fn on_new_connection(&mut self, fd: RawFd) -> Arc<UnsafeCell<HydrogenStream>> {
        // With the passed fd, create your type that implements `hydrogen::Stream`
        // and return it.
    }

    fn on_data_received(&mut self, socket: HydrogenSocket, buffer: Vec<u8>) {
        // Called when a complete, consumer defined, chunk of data has been read.
    }

    fn on_connection_removed(&mut self, fd: RawFd, err: Error) {
        // Called when a connection has been removed from the watch list, with the
        // `std::io::Error` as the reason removed.
    }
}


fn main() {
    hydrogen::begin(Server, hydrogen::Config {
        addr: "0.0.0.0".to_string(),
        port: 1337,
        max_threads: 8,
        pre_allocated: 100000
    });
}

Author

Nathan Sizemore, nathanrsizemore@gmail.com

License

hydrogen is available under the MPL-2.0 license. See the LICENSE file for more info.