C# Async Sockets Server Receive Problems

Question

I have implemented my Server application regarding this post here: http://www.codeguru.com/csharp/csharp/cs_network/sockets/article.php/c8781#Client1

Sum up: I am us

Answer 1

TCP is stream based and not message based. One Read can contain any of the following alternatives:

• A teeny weeny part of message
• A half message
• Excactly one message
• One and a half message
• Two messages

Thus you need to use some kind of method to see if a complete message have arrived. The most common methods are:

• Add a footer (for instance an empty line) which indicates end of message
• Add a fixed length header containing the length of the message

Update

Simple example having just length as header.

Server side:

var buffer = binaryFormmater.Serialize(myobj);
var length = buffer.Length;
networkStream.Send(length);
networkStream.Send(buffer, 0, buffer.Length);

Client side:

var header = new buffer[4];
// TODO: You need to make sure that 4 bytes have been read.
networkStream.Read(header, 0, 4);
var length = BitConverter.ToInt32(buffer);

var readbuffer= new byte[65535];
var bytesLeft = length;
var messageStream = new MemoryStream();
while (bytesLeft > 0)
{
     var read = networkStream.Read(readbuffer, 0, bytesLeft);
     messageStream.Write(readbuffer, 0, read);
     bytesLeft -= read,
}

messageStream.Seek(0, SeekOrigin.Begin);
MyMessage msg = (MyMessage)binForm.Deserialize(messageStream);