Question

Kinda long title, but anyways…

I’ve been looking at these examples, specifically on the parts on writing and reading the size of the message to the byte streams
http://doc.trolltech.com/4.4/network-fortuneclient-client-cpp.html
http://doc.trolltech.com/4.4/network-fortuneserver-server-cpp.html

But I can’t seem to figure it out in C#.

StreamWriter writer = new StreamWriter(tcpClient.GetStream()); writer.Write(data.Length + data); 

This doesn’t work very well at all. Could someone give me a nudge in the right direction?

Answer 1

Generally you would send the length first. Both ends should agree on what a length looks like – for example, you might be happy to use fixed 4-byte length prefix as binary:

  byte[] data = ...   int len = data.Length;   byte[] prefix = Bitconverter.GetBytes(len);   stream.Write(prefix, 0, prefix.Length); // fixed 4 bytes   stream.Write(data, 0, data.Length); 

Obviously the caller needs to do the same – i.e. read the first 4 bytes to get the length. For reading, the receiver should take care not to read too much data. One way is with a limiting stream – for example, this class can be used to get a Stream that won’t read too much.

If you don’t want the overhead of always sending 4 bytes, then some more interesting encodings are possible – for example, using the msb as a continuation block.

For info, protobuf-net is a binary serializer designed around Google’s ‘protocol buffers’ message-based format. It handles a lot of the details for you, and might be of interest if you don’t want to spend lots of time writing serialization code. There are examples for sockets in the QuickStart project, for example here