TagBites.Net

Lightweight and simple TCP client-server .NET library with RMI support.

Install

dotnet add package TagBites.Net

Targets netstandard2.0 and net7.0. The only dependency is Newtonsoft.Json, plus System.Reflection.DispatchProxy on netstandard2.0.

Chat example

A console chat. Every client sends text lines to the server, and the server broadcasts each message to the other clients, together with connect and disconnect notifications.

Client code

var client = new Client("127.0.0.1", 8200);
client.Received += (s, e) => Console.WriteLine(e.Message.ToString());
await client.ConnectAsync();

while (Console.ReadLine() is { } message)
    await client.SendAsync(message);

Server code

var server = new Server("127.0.0.1", 8200);
server.ClientConnected += async (s, e) => await server.SendToAllAsync($"{e.Client} connected", e.Client);
server.ClientDisconnected += async (s, e) => await server.SendToAllAsync($"{e.Client} disconnected", e.Client);
server.Received += async (s, e) => await server.SendToAllAsync($"{e.Client}: {e.Message}", e.Client);
server.Listening = true; // starts a new thread

Console.ReadLine(); // for console application to prevent app from closing

In this example a string type is used for communication, but any serializable objects can be sent/received.

By default Newtonsoft.Json is used for serialization, but it can be replaced with a custom implementation.

Full example in this repository: samples/Chat.

Chat example using RMI (Remote Method Invocation)

The same chat, written as method calls instead of messages. Both sides share two interfaces: the client calls IChatServer.Send on the server, and the server calls IChatClient.OnMessage on every client. Serialization and dispatch happen behind the proxy returned by GetController<T>().

Client code

var client = new Client("127.0.0.1", 10500);
client.Use<IChatClient, ChatClient>();
await client.ConnectAsync();

while (Console.ReadLine() is { } message)
    client.GetController<IChatServer>().Send(message);

The method Use<TControllerInterface, TController>() registers a controller that can be used by the server. The server side can use the IChatClient interface to execute methods implemented by ChatClient on the client's side. The client/server can register many controllers. The controller instance will be created on first use.

GetController<T>() returns a proxy implementing the interface registered on the remote side. Calling a method on it invokes that method on the remote side. A controller method takes primitive or serializable parameters and returns void, Task, or any primitive or serializable type.

Server code

var server = new Server("127.0.0.1", 10500);
server.Use<IChatServer, ChatServer>(client => new ChatServer { Client = client, Server = server });
server.ClientConnected += (s, e) =>
{
    foreach (var client in server.GetClients())
        if (client != e.Client)
            client.GetController<IChatClient>().OnMessage(null, $"Client {e.Client.Identity} connected");

    Console.WriteLine($"Client {e.Client.Identity} connected.");
};
server.ClientDisconnected += (s, e) =>
{
    foreach (var client in server.GetClients())
        client.GetController<IChatClient>().OnMessage(null, $"Client {e.Client.Identity} disconnected");

    Console.WriteLine($"Client {e.Client.Identity} disconnected.");
};
server.Listening = true;

Console.ReadLine();

Classes

public interface IChatClient
{
    void OnMessage(string userName, string message);
}
public class ChatClient : IChatClient 
{
    public void OnMessage(string userName, string message)
    {
        Console.WriteLine(userName == null ? message : $"{userName}: {message}");
    }
}

public interface IChatServer
{
    void Send(string message);
}
public class ChatServer : IChatServer 
{
    public Server Server { get; set; }
    public ServerClient Client { get; set; }

    public void Send(string message)
    {
        Console.WriteLine($"{Client.Identity}: {message}");

        foreach (var client in Server.GetClients())
            if (Client != client)
                client.GetController<IChatClient>().OnMessage(Client.Identity?.ToString(), message);
    }
}

Full example in this repository: samples/ChatWithControllers.

Limitations

There is no message size limit and no rate limiting, so both sides have to be trusted. Authentication is a callback, not a protocol, and credentials travel in plain text unless the connection uses a certificate.

Links

• Guides: Architecture, Authentication, Configuration, Serialization, RMI, Error handling
• Changelog