feat: add route handshake lifecycle

2026-02-23 05:46:59 -05:00
parent 44d426a7c5
commit 5f98e53d62
6 changed files with 355 additions and 0 deletions
--- a/src/NATS.Server/Routes/RouteConnection.cs
+++ b/src/NATS.Server/Routes/RouteConnection.cs
@@ -0,0 +1,81 @@
+using System.Net.Sockets;
+using System.Text;
+
+namespace NATS.Server.Routes;
+
+public sealed class RouteConnection(Socket socket) : IAsyncDisposable
+{
+    private readonly Socket _socket = socket;
+    private readonly NetworkStream _stream = new(socket, ownsSocket: true);
+
+    public string? RemoteServerId { get; private set; }
+    public string RemoteEndpoint => _socket.RemoteEndPoint?.ToString() ?? Guid.NewGuid().ToString("N");
+
+    public async Task PerformOutboundHandshakeAsync(string serverId, CancellationToken ct)
+    {
+        await WriteLineAsync($"ROUTE {serverId}", ct);
+        var line = await ReadLineAsync(ct);
+        RemoteServerId = ParseHandshake(line);
+    }
+
+    public async Task PerformInboundHandshakeAsync(string serverId, CancellationToken ct)
+    {
+        var line = await ReadLineAsync(ct);
+        RemoteServerId = ParseHandshake(line);
+        await WriteLineAsync($"ROUTE {serverId}", ct);
+    }
+
+    public async Task WaitUntilClosedAsync(CancellationToken ct)
+    {
+        var buffer = new byte[1024];
+        while (!ct.IsCancellationRequested)
+        {
+            var bytesRead = await _stream.ReadAsync(buffer, ct);
+            if (bytesRead == 0)
+                return;
+        }
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        await _stream.DisposeAsync();
+    }
+
+    private async Task WriteLineAsync(string line, CancellationToken ct)
+    {
+        var bytes = Encoding.ASCII.GetBytes($"{line}\r\n");
+        await _stream.WriteAsync(bytes, ct);
+        await _stream.FlushAsync(ct);
+    }
+
+    private async Task<string> ReadLineAsync(CancellationToken ct)
+    {
+        var bytes = new List<byte>(64);
+        var single = new byte[1];
+        while (true)
+        {
+            var read = await _stream.ReadAsync(single, ct);
+            if (read == 0)
+                throw new IOException("Route connection closed during handshake");
+
+            if (single[0] == (byte)'\n')
+                break;
+            if (single[0] != (byte)'\r')
+                bytes.Add(single[0]);
+        }
+
+        return Encoding.ASCII.GetString([.. bytes]);
+    }
+
+    private static string ParseHandshake(string line)
+    {
+        if (!line.StartsWith("ROUTE ", StringComparison.OrdinalIgnoreCase))
+            throw new InvalidOperationException("Invalid route handshake");
+
+        var id = line[6..].Trim();
+        if (id.Length == 0)
+            throw new InvalidOperationException("Route handshake missing server id");
+
+        return id;
+    }
+}