Getting Single lines from an async socket

[plasmatwin]

I'm writing an IRC client library in c# using the Aynchronous Socket model in .NET. I am currently at a problem where, when recieving data from the socket, the program simply fills its buffer (a byte[256]) with data from the socket and hands it to me. The problem is that this array could contain a single line (often does) or it could contain half a line (since the line is longer than 256 chars) or it could contain 2 lines (if two lines arrived in the socket in the time it took me to perform the read after recieving the last lot) it could also contain one and a half lines. Therefor I need some code that inspects the array and sepperates it into it's sepperate lines. I have a string builder in my state object for the purpose of storing peices of a line that is split across two reads, but I have no idea on how to do the inspection of the array... here is my state object:

class StateObject
{
	// Size of receive buffer.
	public const int BufferSize = 512;
	// Receive buffer.
	public byte[] buffer = new byte[BufferSize];
	// Received data string.
	public StringBuilder sb = new StringBuilder();
}

ideas?

 

[chiph]

This is basic socket programming.

The key thing to realize is that sockets are a stream-based protocol (it's all just a series of bytes) and not a message-oriented protocol (it's a series of records or lines)

So I would suggest that you pass your array of bytes up to a higher level that is able to interpret the bytes and decide if a complete line has been received.

Yes: remove that part from your buffer and go off and process it (or raise an event and let someone else process it)

No: Append it to your buffer and make another request.

Since you're writing an IRC client, and such clients routinely come under attack, I would also suggest you add a "MaxLineLength" value (say, 2000 characters) to prevent someone from sending you 1,000,000 characters all on one line.

Chip H.


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