Comments on: Sending objects via high speed asynchronous sockets in C# (Serialization + Socket programming)

By: Ciwan

Ciwan — Sat, 12 Feb 2011 16:38:04 +0000

Hello Roy

You were right, you can probably tell I am a n00b to this.

Here is what my code looks like right now:

I haven’t touched the client class, because what I understood from you, is that it was fine !

As you can see in my Product class I have added a Byte Array of size 1024 << would that be enough to hold the byte data from a Product object ?

Also can you please tell me (in code) how I would grab the byte data, and transform it back to a Product object.

I greatly appreciate your help.

Thanks Roy.

By: Roy Triesscheijn

Roy Triesscheijn — Mon, 07 Feb 2011 08:40:45 +0000

Hey Ciwan, your server is only listening for 100ms, you need to add a while(true) loop so that your server keeps listening. Also you’re not doing anything with the data you might receive. After you’ve accepted a connection (this will give you a client object I think) you need to start receiving data, this will probably have you end up with a byte[]. Then you have to convert this byte[] back to a product item.

By: Ciwan

Ciwan — Sun, 06 Feb 2011 16:37:35 +0000

Sorry there is a mistake in my last comment.

What I mean to say was ” Without using Threading ” … My bad

By: Ciwan

Ciwan — Sun, 06 Feb 2011 16:34:37 +0000

Hi Roy

Thanks for the tutorial. I have tried doing the same thing, but without using serialization. I just want two programs (client and server) that will be able to send and receive a product object. Below is the code for the Product class, and the Client class << I think them two are fine. However my Server class (also below) is messed up, I just don't know how to get it to work.

Product Class Code

Client Class Code

Server Class Code

As you can see my server class is hardly doing anything, but the problem is I dont’ know what to do. I know that I have to somehow de-serialize the product object, but I don’t know how I’d go about doing that. Looking at your code didn’t help either

I would greatly appreciate it you could show me how this would be done.

Thank You.

By: Roy Triesscheijn

Roy Triesscheijn — Tue, 05 Oct 2010 06:11:24 +0000

Hey Tobias, thanks for the great comments. And sorry guys that I wasn’t able to create a bigger sample. This article was supposed to be just a quick’n'dirty way to get everybody started .

By: Tobias

Tobias — Mon, 04 Oct 2010 16:43:08 +0000

In solution 2 it has to be

//in the while loop where the server listens set
firstPackage = true;

By: Tobias

Tobias — Mon, 04 Oct 2010 16:40:04 +0000

Hi Iko

campe up with 2 possible solutions.

1) (quick and dirty) try to deserialize each time and catch the exception

readRequest is function Receive, evaluateRequest is function Done

private void readRequest(IAsyncResult result) { Status status = (Status)result.AsyncState; int read = status.socket.EndReceive(result);

if (read > 0) { for (int i = 0; i < read; i++) status.transmissionBuffer.Add(status.buffer[i]); //try to derialize to see if data send completely try { Status receivedStatus = status.deserialize(); evaluateRequest(status); } catch (SerializationException) { Console.WriteLine("read again.."); status.socket.BeginReceive(status.buffer, 0, status.buffer.Length, SocketFlags.None, readRequest, status); } } else evaluateRequest(status); }

2) Much nicer solution is to send the message length at the beginning of each message. This solution fails if the message length exceeds int.MaxValue Bytes. (There is still the long datatype)

//Add in Server following variables private int incomingMessageLength = 0; private Boolean firstPackage = true; byte[] tmpLentgh = new byte[256];


//in the while loop where the server listens set

firstPackage = false;
//modify the Receive function like this

private void Receive(IAsyncResult result)

{

    Status status = (Status)result.AsyncState;

    int read = status.socket.EndReceive(result);
    if (read > 0)

    {

	if(firstPackage){

	    tmpLentgh = new byte[256];

	}
	if (firstPackage)

	{   //first 256 bytes are message length

	    for (int i = 0; i < read; i++)

	    {

		if (i < 256)

		{

		    tmpLentgh[i] = status.buffer[i];

		}

		else status.transmissionBuffer.Add(status.buffer[i]);

	    }

	    BinaryFormatter bin = new BinaryFormatter();

	    MemoryStream mem = new MemoryStream();
	    mem.Write(tmpLentgh, 0, tmpLentgh.Length);

	    mem.Seek(0, 0);

	    incomingMessageLength = (int)bin.Deserialize(mem);

	    firstPackage = false;

	}

	else if (!firstPackage)

	{

	    for (int i = 0; i  status.transmissionBuffer.Count)

	{   //read again

	    Console.WriteLine("read again");

	    status.socket.BeginReceive(status.buffer, 0, status.buffer.Length, SocketFlags.None, Receive, status);

	}

	else Done(status);

   }

   else Done(status);

}
//in the connect function of the client change

byte[] buffer = status.Serialize(); //fills the buffer with data

status.Socket.BeginSend(buffer, 0, buffer.Length, SocketFlags.None, Send, status);
//to:

byte[] buffer = status.serialize();
outgoingMessageLength = buffer.Length;

BinaryFormatter bin = new BinaryFormatter();

MemoryStream mem = new MemoryStream();

bin.Serialize(mem, outgoingMessageLength);

byte[] messageLength = mem.GetBuffer();

List messageByteList = messageLength.ToList();

for (int i = 0; i < buffer.Length; i++) messageByteList.Add(buffer[i]);

buffer = messageByteList.ToArray();

status.socket.BeginSend(buffer, 0, buffer.Length, SocketFlags.None, send, status);

Thank you Roy for this nice tutorial. Pointed me in the right direction

By: Tobias

Tobias — Mon, 04 Oct 2010 14:26:52 +0000

Hi Iko

have the same problem. But didn’t have a solution right now. But still trying …

By: Iko

Iko — Thu, 09 Sep 2010 14:41:41 +0000

Hi
I dont know why, but this program doest work when you try to do this :
example ..
when the buffer in status is 256 bytes and you send message that has exactly 256 bytes.
or in other words when the size of your message is divisible by the size of the buffer .

in server after (read == status.buffer.Length) when it tries BeginReceive it just freeze

can somebody try it and tell me ?

thx..

By: Roy Triesscheijn

Roy Triesscheijn — Sat, 24 Jul 2010 20:38:18 +0000

Hey BigDirty,

Thanks for your comment, I actually tried large texts and it seemed fine (there’s a special check in the code to see if we could expect another fragment). Are you sure my code is faulty? Could be that I missed something. Unfortunately I don’t have the sample project anymore, but please play around a bit and if you’ve isolated the problem let me know .