/// <summary>
/// Callback for when data is available for reading from the underlying stream.
/// </summary>
/// <param name="asyncResult">The async result from the read.</param>
private void ReadComplete(IAsyncResult asyncResult)
{
int bytesRead;
var dataStream = (NetworkStream)asyncResult.AsyncState;
try {
if (tcpClient.Connected && dataStream.CanRead && dataStream.DataAvailable)
{
bytesRead = dataStream.EndRead(asyncResult);
if (bytesRead == 1)
{
var messageBytes = new Collection <byte>();
messageBytes.Add(headerByte[0]);
Collection <byte> lengthBytes = MqttHeader.ReadLengthBytes(dataStream);
int length = MqttHeader.CalculateLength(lengthBytes);
messageBytes.AddRange(lengthBytes);
// we've got the bytes that make up the header, inc the size, read the .
var remainingMessage = new byte[length];
int messageBytesRead = dataStream.Read(remainingMessage, 0, length);
if (messageBytesRead < length)
{
// we haven't got all the message, need to figure oput what to do.
}
messageBytes.AddRange(remainingMessage);
FireDataAvailableEvent(messageBytes);
}
}
// initiate a read for the next byte which will be the header bytes so long as
// we're still connected to the underlying client
if (tcpClient.Connected && networkStream.CanRead)
{
dataStream.BeginRead(headerByte, 0, 1, ReadComplete, dataStream);
}
} catch (IOException ex) {
// close the underlying connection
this.Disconnect();
if (ConnectionDropped != null)
{
ConnectionDropped(this, new ConnectionDroppedEventArgs(ex));
}
}
}
/// <summary>
/// Callback for when data has been read from the underlying network stream.
/// </summary>
/// <param name="asyncResult">The async result from the read.</param>
private void ReadHeaderComplete(IAsyncResult asyncResult)
{
var readWrapper = (ReadWrapper)asyncResult.AsyncState;
try {
var bytesRead = readWrapper.Stream.EndRead(asyncResult);
if (bytesRead == 0)
{
// Nothing read, we will just try another read from the stream.
Log.Debug("Async network stream read returned 0 bytes, continuing to search for header.");
readWrapper.ReadState = ConnectionReadState.Header;
}
else if (tcpClient.Connected && readWrapper.Stream.CanRead)
{
if (readWrapper.ReadState == ConnectionReadState.Header && readWrapper.Stream.DataAvailable)
{
Log.Info("Reading message arriving on the wire.");
readWrapper.MessageBytes.Add(readWrapper.Buffer[0]);
var lengthBytes = MqttHeader.ReadLengthBytes(readWrapper.Stream);
var remainingLength = MqttHeader.CalculateLength(lengthBytes);
// update the read wrapper with the header bytes, and a resized read buffer
// to capture the remaining length.
readWrapper.MessageBytes.AddRange(lengthBytes);
// no content, so yield the message early, else transition to reading the content.
if (remainingLength == 0)
{
Log.Debug("Message receipt complete. Has empty content length so handing off now.");
FireDataAvailableEvent(readWrapper.MessageBytes);
}
else
{
// total bytes of content is the remaining length plus the header.
readWrapper.TotalBytes = remainingLength + readWrapper.MessageBytes.Count;
readWrapper.RecalculateNextReadSize();
readWrapper.ReadState = ConnectionReadState.Content;
}
}
else if (readWrapper.ReadState == ConnectionReadState.Content)
{
// stash what we've read.
readWrapper.MessageBytes.AddRange(readWrapper.Buffer.Take(bytesRead));
Log.Debug(m => m("Message Content read {0:n0} of {1:n0} expected remaining bytes.", bytesRead, readWrapper.TotalBytes));
// if we haven't yet read all of the message repeat the read otherwise if
// we're finished process the message and switch back to waiting for the next header.
if (readWrapper.IsReadComplete)
{
// reset the read buffer to accommodate the remaining length (last - what was read)
readWrapper.RecalculateNextReadSize();
}
else
{
Log.Debug(m => m("Message receipt complete ({0:n0} total bytes including all headers), handing off to handlers.", readWrapper.MessageBytes.Count));
readWrapper.ReadState = ConnectionReadState.Header;
FireDataAvailableEvent(readWrapper.MessageBytes);
}
}
// if we've switched to reading a header then recreate the read dwrapper for the next message
if (readWrapper.ReadState == ConnectionReadState.Header)
{
readWrapper = new ReadWrapper(readWrapper.Stream);
}
// we can still read etc
// initiate a read for the next set of bytes which will be the header bytes so long as
// we're still connected to the underlying client
readWrapper.Stream.BeginRead(readWrapper.Buffer, 0, readWrapper.NextReadSize, ReadHeaderComplete, readWrapper);
}
} catch (IOException ex) {
Log.Debug("Error occurred during async read from broker network stream. Initiating broker disconnect", ex);
// close the underlying connection
this.Disconnect();
if (ConnectionDropped != null)
{
ConnectionDropped(this, new ConnectionDroppedEventArgs(ex));
}
}
}
