using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Text.RegularExpressions;
namespace Libmpc
{
///
/// Keeps the connection to the MPD server and handels the most basic structure of the
/// MPD protocol. The high level commands are handeled in the
/// class.
///
public class MpcConnection
{
///
/// Is fired when a connection to a MPD server is established.
///
public event EventHandler Connected;
///
/// Is fired when the connection to the MPD server is closed.
///
public event EventHandler Disconnected;
private static readonly string FIRST_LINE_PREFIX = "OK MPD ";
private static readonly string OK = "OK";
private static readonly string ACK = "ACK";
private static readonly Regex ACK_REGEX = new Regex("^ACK \\[(?[0-9]*)@(?[0-9]*)] \\{(?[a-z]*)} (?.*)$");
private IPEndPoint _ipEndPoint;
private TcpClient _tcpClient;
private NetworkStream _networkStream;
private StreamReader _reader;
private StreamWriter _writer;
private string _version;
///
/// If the connection to the MPD is connected.
///
public bool IsConnected { get { return (_tcpClient != null) && _tcpClient.Connected; } }
///
/// The version of the MPD.
///
public string Version { get { return _version; } }
private bool _autoConnect = false;
///
/// If a connection should be established when a command is to be
/// executed in disconnected state.
///
public bool AutoConnect
{
get{ return _autoConnect; }
set { _autoConnect = value; }
}
///
/// Creates a new MpdConnection.
///
/// The IPEndPoint of the MPD server.
public MpcConnection(IPEndPoint server)
{
Server = server;
}
///
/// The IPEndPoint of the MPD server.
///
/// When a conenction to a MPD server is already established.
public IPEndPoint Server
{
get { return _ipEndPoint; }
set
{
if (IsConnected)
throw new AlreadyConnectedException();
_ipEndPoint = value;
ClearConnectionFields();
}
}
///
/// Connects to the MPD server who's IPEndPoint was set in the Server property.
///
/// If no IPEndPoint was set to the Server property.
public void Connect()
{
if (_ipEndPoint == null)
throw new InvalidOperationException("Server IPEndPoint not set.");
if (IsConnected)
throw new AlreadyConnectedException();
_tcpClient = new TcpClient();
var connection = _tcpClient.ConnectAsync(_ipEndPoint.Address, _ipEndPoint.Port);
connection.Wait();
_networkStream = _tcpClient.GetStream();
_reader = new StreamReader(_networkStream, Encoding.UTF8);
_writer = new StreamWriter(_networkStream, Encoding.UTF8);
_writer.NewLine = "\n";
string firstLine = _reader.ReadLine();
if( !firstLine.StartsWith( FIRST_LINE_PREFIX ) )
{
Disconnect();
throw new InvalidDataException("Response of mpd does not start with \"" + FIRST_LINE_PREFIX + "\"." );
}
_version = firstLine.Substring(FIRST_LINE_PREFIX.Length);
_writer.WriteLine();
_writer.Flush();
ReadResponse();
Connected?.Invoke(this, EventArgs.Empty);
}
///
/// Disconnects from the current MPD server.
///
public void Disconnect()
{
if (_tcpClient == null)
return;
_networkStream.Dispose();
ClearConnectionFields();
Disconnected?.Invoke(this, EventArgs.Empty);
}
///
/// Executes a simple command without arguments on the MPD server and returns the response.
///
/// The command to execute.
/// The MPD server response parsed into a basic object.
/// If the command contains a space of a newline charakter.
public MpdResponse Exec(string command)
{
if (command == null)
throw new ArgumentNullException("command");
if (command.Contains(" "))
throw new ArgumentException("command contains space");
if (command.Contains("\n"))
throw new ArgumentException("command contains newline");
CheckConnected();
try
{
_writer.WriteLine(command);
_writer.Flush();
return ReadResponse();
}
catch (Exception)
{
try { Disconnect(); }
catch (Exception) { }
return null; // TODO: Create Null Object for MpdResponse
}
}
///
/// Executes a MPD command with arguments on the MPD server.
///
/// The command to execute.
/// The arguments of the command.
/// The MPD server response parsed into a basic object.
/// If the command contains a space of a newline charakter.
public MpdResponse Exec(string command, string[] argument)
{
if (command == null)
throw new ArgumentNullException("command");
if (command.Contains(" "))
throw new ArgumentException("command contains space");
if (command.Contains("\n"))
throw new ArgumentException("command contains newline");
if (argument == null)
throw new ArgumentNullException("argument");
for (int i = 0; i < argument.Length; i++)
{
if (argument[i] == null)
throw new ArgumentNullException("argument[" + i + "]");
if (argument[i].Contains("\n"))
throw new ArgumentException("argument[" + i + "] contains newline");
}
CheckConnected();
try
{
_writer.Write(command);
foreach (string arg in argument)
{
_writer.Write(' ');
WriteToken(arg);
}
_writer.WriteLine();
_writer.Flush();
return ReadResponse();
}
catch (Exception)
{
try { Disconnect(); } catch (Exception) { }
throw;
}
}
private void CheckConnected()
{
if (!IsConnected)
{
if (_autoConnect)
Connect();
else
throw new NotConnectedException();
}
}
private void WriteToken(string token)
{
if (token.Contains(" "))
{
_writer.Write("\"");
foreach (char chr in token)
if (chr == '"')
_writer.Write("\\\"");
else
_writer.Write(chr);
}
else
_writer.Write(token);
}
private MpdResponse ReadResponse()
{
List ret = new List();
string line = _reader.ReadLine();
while (!(line.Equals(OK) || line.StartsWith(ACK)))
{
ret.Add(line);
line = _reader.ReadLine();
}
if (line.Equals(OK))
return new MpdResponse(new ReadOnlyCollection(ret));
else
{
Match match = ACK_REGEX.Match(line);
if (match.Groups.Count != 5)
throw new InvalidDataException( "Error response not as expected" );
return new MpdResponse(
int.Parse( match.Result("${code}") ),
int.Parse( match.Result("${nr}") ),
match.Result("${command}"),
match.Result("${message}"),
new ReadOnlyCollection(ret)
);
}
}
private void ClearConnectionFields()
{
_tcpClient?.Dispose();
_networkStream?.Dispose();
_reader?.Dispose();
_writer?.Dispose();
_version = string.Empty;
}
}
}