/// <summary>
/// Recebe os 2 primeiros bytes do pacote (cabeçalho) de forma assincrona
/// estes bytes representam o tamanho do resto do pacote
/// isso é necessario para realizar a quebra da stream em datagramas
/// </summary>
/// <param name="result"></param>
private void AsyncReceiveHeader(IAsyncResult result)
{
try
{
SocketError socketError;
if (!asyncState.Socket.Connected)
{
return;
}
// representa a quantidade de bytes que foi recebido, caso ocorra erro ele sera armazenado em 'socketError'
int size = asyncState.Socket.EndReceive(result, out socketError);
if (socketError == SocketError.Success && size == 2)
{
asyncState.ReceiveBufferHeader = new byte[size];
Buffer.BlockCopy(asyncState.Buffer, 0, asyncState.ReceiveBufferHeader, 0, size);
// tamanho do pacote
ushort packetHeaderLength = BitConverter.ToUInt16(asyncState.ReceiveBufferHeader, 0);
// buffer de recebimento setado para o tamanho do pacote
asyncState.ReceivedBuffer = new byte[packetHeaderLength];
// chama AsyncReceiveBody para receber o pacote
asyncState.Socket.BeginReceive(asyncState.ReceivedBuffer, 0, packetHeaderLength,
SocketFlags.None, AsyncReceiveBody, asyncState);
}
else
{
// se ocorreu erro desconectar
asyncState.BeginDisconnect();
}
}
catch (SocketException ex)
{
if (ex.SocketErrorCode != SocketError.Disconnecting &&
ex.SocketErrorCode != SocketError.NotConnected &&
ex.SocketErrorCode != SocketError.ConnectionReset &&
ex.SocketErrorCode != SocketError.ConnectionAborted &&
ex.SocketErrorCode != SocketError.Shutdown)
{
Debug.WriteLine(ex);
}
}
}
/// <summary>
/// Recebe dados de forma assíncrona
/// </summary>
/// <param name="result"></param>
private void AsyncReceive(IAsyncResult result)
{
try
{
SocketError socketError;
if (!asyncState.Socket.Connected)
{
return;
}
// representa a quantidade de bytes que foi recebido, caso ocorra erro ele sera armazenado em 'socketError'
int size = asyncState.Socket.EndReceive(result, out socketError);
if (socketError == SocketError.Success && size != 0)
{
// seta o tamanho do buffer de pacote
asyncState.ReceivedBuffer = new byte[size];
// passa os dados do buffer de recebimento para o buffer de pacote
Buffer.BlockCopy(asyncState.Buffer, 0, asyncState.ReceivedBuffer, 0, size);
// chama evento de recebimento
asyncState.AsyncSocket.OnReceive(new ReceiveEventArgs(asyncState));
// Volta a receber dados
BeginReceive();
}
else
{
// se ocorreu erro desconectar
asyncState.BeginDisconnect();
}
}
catch (SocketException ex)
{
if (ex.SocketErrorCode != SocketError.Disconnecting &&
ex.SocketErrorCode != SocketError.NotConnected &&
ex.SocketErrorCode != SocketError.ConnectionReset &&
ex.SocketErrorCode != SocketError.ConnectionAborted &&
ex.SocketErrorCode != SocketError.Shutdown)
{
Debug.WriteLine(ex);
}
}
}