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TCP networking (server + client)

Stand up a TCP server, subscribe to its lifecycle and data events, then round-trip a message from a client.

What you'll build

A SquidTcpServer (SquidStd.Network) bound to a loopback endpoint that logs client connections and received payloads, plus a SquidStdTcpClient that connects and sends bytes. The server run is guarded behind --run so dotnet run returns immediately by default.

Prerequisites

  • .NET 10 SDK
  • dotnet add package SquidStd.Network
  • A free local TCP port (the sample uses 9099 on loopback)

Steps

1. Create the server and subscribe to events

Construct SquidTcpServer with an IPEndPoint, then subscribe to OnClientConnect and OnDataReceived. The data event carries the source client and the payload as ReadOnlyMemory<byte>.


var endPoint = new IPEndPoint(IPAddress.Loopback, 9099);
var server = new SquidTcpServer(endPoint);

server.OnClientConnect += (_, args) =>
    Console.WriteLine($"Client connected: session {args.Client.SessionId}");

server.OnDataReceived += (_, args) =>
    Console.WriteLine(
        $"Received {args.Data.Length} byte(s): {Encoding.UTF8.GetString(args.Data.Span)}"
    );

2. Start the server and connect a client

StartAsync begins accepting connections. SquidStdTcpClient.ConnectAsync opens an outbound connection and starts its receive loop; SendAsync writes the payload, which surfaces on the server's OnDataReceived.


await server.StartAsync(CancellationToken.None);

var client = await SquidStdTcpClient.ConnectAsync(endPoint);
await client.SendAsync(Encoding.UTF8.GetBytes("hello squid"), CancellationToken.None);

await Task.Delay(200);

await client.DisposeAsync();
await server.DisposeAsync();

Run it

dotnet run --project samples/SquidStd.Samples.Networking -- --run

Without --run the program just prints a hint and exits. With --run it prints the connecting session and the received message (hello squid).

How it works

SquidTcpServer recreates its listening socket on every StartAsync, so Stop/Start cycles are supported. Each accepted socket is wrapped in a SquidStdTcpClient whose events (OnConnected, OnDataReceived, OnDisconnected, OnException) are re-raised by the server. An optional INetFramer lets you emit one OnDataReceived per logical frame instead of per socket read, and INetMiddleware components can transform inbound and outbound payloads.

See also

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