Sending Array of Bytes from Client to server?

Question

I've a tcp based client-server application. I'm able to send and receive strings, but don't know how to send an array of bytes instead.

I'm using the following function to send a string from the client to the server:

static void Send(string msg)
{
    try
    {
        StreamWriter writer = new StreamWriter(client.GetStream());
        writer.WriteLine(msg);
        writer.Flush();
    }
    catch
    {
    }
}

Communication example

Client sends a string:

Send("CONNECTED| 84.56.32.14")

Server receives a string:

void clientConnection_ReceivedEvent(Connection client, String Message)
{
    string[] cut = Message.Split('|');
    switch (cut[0])
    {
        case "CONNECTED":
            Invoke(new _AddClient(AddClient), client, null);
            break;
        case "STATUS":
            Invoke(new _Status(Status), client, cut[1]);
            break;
    }
}

I need some help to modify the functions above in order to send and receive an array of bytes in addition to strings. I want to make a call like this:

Send("CONNECTED | 15.21.21.32", myByteArray);

Marc Gravell Marc Gravell · Accepted Answer · 2012-05-05T18:41:27

Just use Stream - no need for a writer here. Basic sending is simple:

stream.Write(data, 0, data.Length);

However you probably need to think about "framing", i.e. how it knows where each sun-message starts and ends. With strings this is often special characters (maybe new line) - but this is rarely possible in raw binary. A common appoach is to proceed the message with the number f bytes to follow, in a pre-defined way (maybe network-byte-order fixed 4 byte unsigned integer, for example).

Reading: again, use the Stream Read method, but understand that you always need t check the return value; just because you say "read at most 20 bytes" doesn't mean you get that many, even if more is coming - you could read 3,3,3,11 bytes for example (unlikely, but you see what I mean). For example, to read exactly 20 bytes:

var buffer = new byte[...];
int count = 20, read, offset = 0;
while(count > 0 && ((read = source.Read(buffer, offset, count)) > 0) {
    offset += read;
    count -= read;
}
if(count != 0) throw new EndOfStreamException();

Sending Array of Bytes from Client to server?

3 Answers