jellyfin/Emby.Server.Implementations/Udp/UdpServer.cs
2018-09-12 19:26:21 +02:00

291 lines
9.0 KiB
C#

using MediaBrowser.Controller;
using MediaBrowser.Model.ApiClient;
using MediaBrowser.Model.Logging;
using MediaBrowser.Model.Serialization;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using MediaBrowser.Model.Events;
using MediaBrowser.Model.Net;
namespace Emby.Server.Implementations.Udp
{
/// <summary>
/// Provides a Udp Server
/// </summary>
public class UdpServer : IDisposable
{
/// <summary>
/// The _logger
/// </summary>
private readonly ILogger _logger;
private bool _isDisposed;
private readonly List<Tuple<string, bool, Func<string, IpEndPointInfo, Encoding, CancellationToken, Task>>> _responders = new List<Tuple<string, bool, Func<string, IpEndPointInfo, Encoding, CancellationToken, Task>>>();
private readonly IServerApplicationHost _appHost;
private readonly IJsonSerializer _json;
/// <summary>
/// Initializes a new instance of the <see cref="UdpServer" /> class.
/// </summary>
public UdpServer(ILogger logger, IServerApplicationHost appHost, IJsonSerializer json, ISocketFactory socketFactory)
{
_logger = logger;
_appHost = appHost;
_json = json;
_socketFactory = socketFactory;
AddMessageResponder("who is EmbyServer?", true, RespondToV2Message);
AddMessageResponder("who is MediaBrowserServer_v2?", false, RespondToV2Message);
}
private void AddMessageResponder(string message, bool isSubstring, Func<string, IpEndPointInfo, Encoding, CancellationToken, Task> responder)
{
_responders.Add(new Tuple<string, bool, Func<string, IpEndPointInfo, Encoding, CancellationToken, Task>>(message, isSubstring, responder));
}
/// <summary>
/// Raises the <see cref="E:MessageReceived" /> event.
/// </summary>
private async void OnMessageReceived(GenericEventArgs<SocketReceiveResult> e)
{
var message = e.Argument;
var encoding = Encoding.UTF8;
var responder = GetResponder(message.Buffer, message.ReceivedBytes, encoding);
if (responder == null)
{
encoding = Encoding.Unicode;
responder = GetResponder(message.Buffer, message.ReceivedBytes, encoding);
}
if (responder != null)
{
var cancellationToken = CancellationToken.None;
try
{
await responder.Item2.Item3(responder.Item1, message.RemoteEndPoint, encoding, cancellationToken).ConfigureAwait(false);
}
catch (OperationCanceledException)
{
}
catch (Exception ex)
{
_logger.ErrorException("Error in OnMessageReceived", ex);
}
}
}
private Tuple<string, Tuple<string, bool, Func<string, IpEndPointInfo, Encoding, CancellationToken, Task>>> GetResponder(byte[] buffer, int bytesReceived, Encoding encoding)
{
var text = encoding.GetString(buffer, 0, bytesReceived);
var responder = _responders.FirstOrDefault(i =>
{
if (i.Item2)
{
return text.IndexOf(i.Item1, StringComparison.OrdinalIgnoreCase) != -1;
}
return string.Equals(i.Item1, text, StringComparison.OrdinalIgnoreCase);
});
if (responder == null)
{
return null;
}
return new Tuple<string, Tuple<string, bool, Func<string, IpEndPointInfo, Encoding, CancellationToken, Task>>>(text, responder);
}
private async Task RespondToV2Message(string messageText, IpEndPointInfo endpoint, Encoding encoding, CancellationToken cancellationToken)
{
var parts = messageText.Split('|');
var localUrl = await _appHost.GetLocalApiUrl(cancellationToken).ConfigureAwait(false);
if (!string.IsNullOrEmpty(localUrl))
{
var response = new ServerDiscoveryInfo
{
Address = localUrl,
Id = _appHost.SystemId,
Name = _appHost.FriendlyName
};
await SendAsync(encoding.GetBytes(_json.SerializeToString(response)), endpoint, cancellationToken).ConfigureAwait(false);
if (parts.Length > 1)
{
_appHost.EnableLoopback(parts[1]);
}
}
else
{
_logger.Warn("Unable to respond to udp request because the local ip address could not be determined.");
}
}
/// <summary>
/// The _udp client
/// </summary>
private ISocket _udpClient;
private readonly ISocketFactory _socketFactory;
/// <summary>
/// Starts the specified port.
/// </summary>
/// <param name="port">The port.</param>
public void Start(int port)
{
_udpClient = _socketFactory.CreateUdpSocket(port);
Task.Run(() => BeginReceive());
}
private readonly byte[] _receiveBuffer = new byte[8192];
private void BeginReceive()
{
if (_isDisposed)
{
return;
}
try
{
var result = _udpClient.BeginReceive(_receiveBuffer, 0, _receiveBuffer.Length, OnReceiveResult);
if (result.CompletedSynchronously)
{
OnReceiveResult(result);
}
}
catch (ObjectDisposedException)
{
}
catch (Exception ex)
{
_logger.ErrorException("Error receiving udp message", ex);
}
}
private void OnReceiveResult(IAsyncResult result)
{
if (_isDisposed)
{
return;
}
try
{
var socketResult = _udpClient.EndReceive(result);
OnMessageReceived(socketResult);
}
catch (ObjectDisposedException)
{
}
catch (Exception ex)
{
_logger.ErrorException("Error receiving udp message", ex);
}
BeginReceive();
}
/// <summary>
/// Called when [message received].
/// </summary>
/// <param name="message">The message.</param>
private void OnMessageReceived(SocketReceiveResult message)
{
if (_isDisposed)
{
return;
}
if (message.RemoteEndPoint.Port == 0)
{
return;
}
try
{
OnMessageReceived(new GenericEventArgs<SocketReceiveResult>
{
Argument = message
});
}
catch (Exception ex)
{
_logger.ErrorException("Error handling UDP message", ex);
}
}
/// <summary>
/// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
/// </summary>
public void Dispose()
{
Dispose(true);
}
/// <summary>
/// Releases unmanaged and - optionally - managed resources.
/// </summary>
/// <param name="dispose"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
protected virtual void Dispose(bool dispose)
{
if (dispose)
{
_isDisposed = true;
if (_udpClient != null)
{
_udpClient.Dispose();
}
}
}
public async Task SendAsync(byte[] bytes, IpEndPointInfo remoteEndPoint, CancellationToken cancellationToken)
{
if (_isDisposed)
{
throw new ObjectDisposedException(GetType().Name);
}
if (bytes == null)
{
throw new ArgumentNullException("bytes");
}
if (remoteEndPoint == null)
{
throw new ArgumentNullException("remoteEndPoint");
}
try
{
await _udpClient.SendToAsync(bytes, 0, bytes.Length, remoteEndPoint, cancellationToken).ConfigureAwait(false);
_logger.Info("Udp message sent to {0}", remoteEndPoint);
}
catch (OperationCanceledException)
{
}
catch (Exception ex)
{
_logger.ErrorException("Error sending message to {0}", ex, remoteEndPoint);
}
}
}
}