Created
August 4, 2020 22:48
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| using System; | |
| using System.Collections.Concurrent; | |
| using System.IO; | |
| using System.Net.Sockets; | |
| using System.Text; | |
| using System.Threading; | |
| using System.Threading.Tasks; | |
| namespace MihuBot.Helpers | |
| { | |
| public class MinecraftRCON | |
| { | |
| private readonly TcpClient _tcp; | |
| private readonly Stream _stream; | |
| private readonly SemaphoreSlim _asyncLock; | |
| private int _idCounter = new Random().Next(1_000_000, 10_000_000); | |
| private DateTime _lastCommandTime; | |
| private readonly Timer _cleanupTimer; | |
| private readonly ConcurrentDictionary<int, TaskCompletionSource<string>> _pendingRequests; | |
| public bool Invalid { get; private set; } = false; | |
| private MinecraftRCON(TcpClient tcp) | |
| { | |
| _tcp = tcp; | |
| _stream = _tcp.GetStream(); | |
| _asyncLock = new SemaphoreSlim(1, 1); | |
| _lastCommandTime = DateTime.UtcNow; | |
| _pendingRequests = new ConcurrentDictionary<int, TaskCompletionSource<string>>(); | |
| _cleanupTimer = new Timer(s => | |
| { | |
| _asyncLock.Wait(); | |
| if (DateTime.UtcNow.Subtract(_lastCommandTime) > TimeSpan.FromSeconds(20)) | |
| { | |
| Cleanup(); | |
| } | |
| _asyncLock.Release(); | |
| }, null, TimeSpan.FromSeconds(20), TimeSpan.FromSeconds(20)); | |
| Task.Run(async () => | |
| { | |
| while (!Invalid) | |
| { | |
| try | |
| { | |
| (int id, string response) = await ReceiveResponseAsync(); | |
| if (!_pendingRequests.TryRemove(id, out var tcs)) | |
| throw new Exception("Invalid response ID"); | |
| tcs.TrySetResult(response); | |
| } | |
| catch (Exception ex) | |
| { | |
| Cleanup(ex); | |
| } | |
| } | |
| }); | |
| } | |
| public async Task<string> SendCommandAsync(string command) | |
| { | |
| return await SendRawPacketAsync(command, packetType: 2); | |
| } | |
| private async Task<string> SendRawPacketAsync(string command, int packetType) | |
| { | |
| int id = Interlocked.Increment(ref _idCounter); | |
| byte[] packet = new byte[14 + command.Length]; | |
| BitConverter.TryWriteBytes(packet, 10 + command.Length); | |
| BitConverter.TryWriteBytes(packet.AsSpan(4), id); | |
| BitConverter.TryWriteBytes(packet.AsSpan(8), packetType); | |
| Encoding.ASCII.GetBytes(command, packet.AsSpan(12)); | |
| var tcs = new TaskCompletionSource<string>(TaskCreationOptions.RunContinuationsAsynchronously); | |
| _pendingRequests.TryAdd(id, tcs); | |
| await _asyncLock.WaitAsync(); | |
| try | |
| { | |
| if (Invalid) | |
| throw new Exception("Invalid RCON"); | |
| _lastCommandTime = DateTime.UtcNow; | |
| await _stream.WriteAsync(packet); | |
| } | |
| catch (Exception ex) | |
| { | |
| Cleanup(ex); | |
| throw; | |
| } | |
| finally | |
| { | |
| _asyncLock.Release(); | |
| } | |
| return await tcs.Task; | |
| } | |
| private async Task<(int, string)> ReceiveResponseAsync() | |
| { | |
| byte[] header = new byte[12]; | |
| int read = 0; | |
| while (read < header.Length) | |
| { | |
| int newRead = await _stream.ReadAsync(header.AsMemory(read)); | |
| if (newRead == 0) | |
| throw new Exception("Connection closed"); | |
| read += newRead; | |
| } | |
| int length = BitConverter.ToInt32(header) - 8; | |
| if (length < 2 || length > 16 * 1024) | |
| throw new Exception("Invalid reponse length"); | |
| byte[] response = new byte[length]; | |
| read = 0; | |
| while (read < response.Length) | |
| { | |
| int newRead = await _stream.ReadAsync(response.AsMemory(read)); | |
| if (newRead == 0) | |
| throw new Exception("Connection closed"); | |
| read += newRead; | |
| } | |
| return (BitConverter.ToInt32(header.AsSpan(4)), Encoding.ASCII.GetString(response.AsSpan(0, response.Length - 2))); | |
| } | |
| private void Cleanup(Exception ex = null) | |
| { | |
| Invalid = true; | |
| try | |
| { | |
| _tcp.Close(); | |
| } | |
| catch { } | |
| try | |
| { | |
| _cleanupTimer.Dispose(); | |
| } | |
| catch { } | |
| try | |
| { | |
| ex ??= new Exception("RCON failure"); | |
| foreach (var tcs in _pendingRequests.Values) | |
| tcs.TrySetException(ex); | |
| } | |
| catch { } | |
| } | |
| public static async Task<MinecraftRCON> ConnectAsync(string hostname, string password, int port = 25575) | |
| { | |
| TcpClient tcp = new TcpClient(); | |
| tcp.SendTimeout = Math.Min(tcp.SendTimeout, 10_000); | |
| tcp.ReceiveTimeout = Math.Min(tcp.ReceiveTimeout, 10_000); | |
| await tcp.ConnectAsync(hostname, port); | |
| var rcon = new MinecraftRCON(tcp); | |
| await rcon.SendRawPacketAsync(password, packetType: 3); | |
| return rcon; | |
| } | |
| } | |
| } |
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