Grubbnet

Grubbnet is a lightweight TCP client/server library, meant for writing networked applications and games. It is basically an evolution and combination of all the TCP boilerplate I usually have to write whenever I work on a networked project.

Grubbnet abstracts socket code, keeps track of connections, and delivers everything back to the developer in a nice list of events. Instead of dealing with raw bytes, Grubbnet operates based on packets that the developer can define. Handling these packets is as simple as grabbing an iterator over the incoming packet queue.

I'm using this crate to develop an online RPG, Antorum. If you want to use it, or are already using it for a project, get in touch!

Usage

Add this to your Cargo.toml:

[dependencies]
grubbnet = "0.1"

Hosting a barebones server:

let mut server = Server::host("127.0.0.1", 7667, 32)?;
loop {
    // Run the network tick and process any events it generates
    for event in server.tick().iter() {
        match event {
            ServerEvent::ClientConnected(token, addr) => {}
            ServerEvent::ClientDisconnected(token) => {}
            ServerEvent::ConnectionRejected(addr) => {}
            ServerEvent::ReceivedPacket(token, byte_count) => {}
            ServerEvent::SentPacket(token, byte_count) => {}
            _ => eprintln!("Unhandled ServerEvent!"),
        }
    }

    // Process incoming packets
    for (token, packet) in server.drain_incoming_packets().iter() {
        match packet.header.id {
            0x00 => { 
                // Deserialize and handle, however you like
            }
            _ => eprintln!("Unhandled packet! id: {}", packet.header.id)
        }
    }
}

Examples

I have written one example so far, which is a simple ping server and client.

cargo run --example simple_server
cargo run --example simple_client

The server will run, waiting for clients to connect and send PingPackets, responding with PongPackets. The client will connect and send PingPackets on an interval. When 5 pings are sent, the server will kick the client.

Both the simple_server and simple_client define the PingPacket and PongPacket. When using the crate for real, if possible you should store packet definitions in a common crate. Also, it goes without saying that these two packets didn't need to be separate types. However, I wanted to demonstrate the pattern of having client-only and server-only packets.

Optional Crate Feature - Crypto

There is one optional feature in this crate, crypto. Enabling it will give you access to the grubbnet::crypto module, which is a tiny wrapper around some openssl and bcrypt stuff for decrypting bytes with a private key, and hashing/verifying strings. This is useful for writing packets with sensitive data. I need to write more about how this is used, but for now just know that if you enable this you are required to have the openssl development libraries installed on your machine.

// Decrypt some bytes
let (decrypted_bytes, decrypted_len) = grubbnet::crypto::decrypt(rsa, &encrypted_bytes)
    .expect("Failed to decrypt password!");

// Convert those bytes into a UTF-8 plaintext password
let plaintext_password = str::from_utf8(&decrypted_bytes[0..decrypted_len])
    .expect("Password was invalid UTF-8!");

// Verify plaintext password against some hashed password
if grubbnet::crypto::verify(plaintext_password, hashed_password)? {
    println!("Authorized!");
}

License

Grubbnet is distributed under the terms of the MIT license. See LICENSE for more details.