WebScocket Sever Lib For .NET 4.5

Introduction

This library provides a Websocket Server, coded with TCPListener and TPCClient classes to implement a server wich can works in any OS wich support Microsoft .Net Framework 4.5 or Microsoft.Net.Core 2.1.

Requirementes

• Visual Studio 2017 Communitiy (For Windows).
• Microsoft .Net 4.5 (For Windows)
• Visual Studio 8.2.5 or higer (For Mac)
• Microsoft Net Core 2.1 (For MAC)

Basic concepts

The repository has two projects:

• WebSocket: Projet wich has the code for WebSocket library.
• Sample: Project wich shows how to use the library.

## Main Classes

• WebSocketServer sets the socket listener to wait for new connections and raise an event with the new connection accepted.
• WebSocketClient handles the communication pear to pear, allowing send and receive messages, get debug message and error messages, as well.

Server events

public void OnStartEvent();
public void OnStopEvent();
public void OnErrorEvent(int err_code, string err_desc);
public void OnNewConnectionEvent(WebSocketClient client);

Client events

public void OnStartEvent();
public void OnStopEvent();
public void OnErrorEvent(int err_code, string err_desc);
public void OnTextMessageEvent(string data);
public void OnBinaryMessageEvent(byte[] data);
public void OnDebugEvent(string message);

Using WebSocket Server

Creating a single WebSocketServer:

WebSocketServer wsserver = new WebSocketServer(IPAddress.Any, port);

Creating a WebSocketServer with SSL:

WebSocketServer wsserver = new WebSocketServer(IPAddress.Any, port,CERT_PATH,"w0rk1ng",System.Security.Authentication.SslProtocols.Tls12);

Link its events:

wsserver.OnSartedEvent += OnStated;
wsserver.OnStopEvent += OnStop;
wsserver.OnNewConnectionEvent += OnNewConnection;
wsserver.OnErrorEvent += OnError;

Handle a new connection:

public void OnNewConnection(WebSocketClient cnx)
{
    System.Console.WriteLine("Server::OnNewConnection: New Connectionwas accepted.");

    Client clt = new Client(cnx);
    clients.Enqueue(clt);
    clt.OnLine();
}

The new connection (WebSocketClient) si delegate into a new class wich will be handled the communication between pears.

In case that there would be and error, the OnErrorEvent will report this event and its information:

public void OnError(int code, string desc)
{
    System.Console.WriteLine(string.Format("Server::OnError: Code: {0}; Desc: {1}", code, desc));
}

Using WebSocket Client

In case of Debug information is requiered, use the property DebugOn, from WebSocketClient to activate all the debug messages through the event OnDebugEvent.

Before start communication, link events and, if you need it, turn on the debug messages, as it shows in the example below:

public Client(WebSocketClient socket)
{
    ws = socket;
    ws.DebugOn = true;

    ws.OnDebugEvent += Debugger;
    ws.OnErrorEvent += WSErrors;
    ws.OnStartEvent += WSStarted;
    ws.OnStopEvent += WSStopped;
    ws.OnTextMessageEvent += WSOnTextMessage;
    ws.OnBinaryMessageEvent += WSOnBynaryMessage;
}

Detect the start of communication through the method linked to OnStartEvent:

private void WSStarted()
{
    System.Console.WriteLine("WS Client was started.");
}

Detect the end of communication,through the method linked to OnStopEvent:

private void WSStopped()
{
    System.Console.WriteLine("WS Client was stopped.");
}

Detect an error with the WebSocketClient through the method linked to OnErrorEvent:

private void WSErrors(int errCode, string errdesc)
{
    System.Console.WriteLine("ERROR [" + errCode +"]: " + errdesc);
}

Get the Debug message if the debug property is turn on, through the method linked to OnDebugEvent:

private void Debugger(string logMessage)
{
    System.Console.WriteLine("DEBUG:" + logMessage);
}

To get a Text Message through the method linked to OnTextMessageEvent::

private void WSOnTextMessage(string data)
{
    System.Console.WriteLine("TXT In: [" + data + "].");
    ws.SendTextMessage("ECHO: " + data);
}

To get a Binary Message through the method linked to OnBinaryMessageEvent::

private void WSOnBynaryMessage(byte[] data)
{
    System.Console.WriteLine("BNR In: [" + data + "].");
}

To send mesage use the methods:

• SendTextMessage(string message) To send a Text message.
• SendBinaryMessage(byte[] buffer) To send a Binary message.

Creating a Cerified for SSL

Firts of all, keep at hand all the information which is required to create a new certified, i.e.:

• Password for PFX: w0rk1ng
• Key Length: 512
• Algorithm: RSA
• Country Name: MX
• State or Province Name: CDMX
• Locality Name: CDMX
• Organization Name: My Company
• Organizational Unit Name: Desarrollo
• Common Name: DEV
• Email Address: myuser@mydomain.com.mx
• Amoutn of valid days: 5000

Important: The Password for PFX will be used get the certifies.

1. Creating a SelfSigned Certified

openssl req -new -x509 -days 5000 -key isat_key.pem -out isat_cert.pem

For example:

$ openssl req -new -x509 -days 5000 -key isat_key.pem -out isat_cert.pem
  You are about to be asked to enter information that will be incorporated
  into your certificate request.
  What you are about to enter is what is called a Distinguished Name or a DN.
  There are quite a few fields but you can leave some blank
  For some fields there will be a default value,
  If you enter '.', the field will be left blank.
  -----
  Country Name (2 letter code) [AU]:MX
  State or Province Name (full name) [Some-State]:CDMX
  Locality Name (eg, city) []:CDMX
  Organization Name (eg, company) [Internet Widgits Pty Ltd]:My Company
  Organizational Unit Name (eg, section) []:Desarrollo
  Common Name (e.g. server FQDN or YOUR name) []:DEV
  Email Address []:myuser@mydomain.com.mx

2. Generating a PFX file

openssl pkcs12 -export -out certificate.pfx -inkey isat_key.pem -in isat_cert.pem

For example:

$ openssl pkcs12 -export -out certificate.pfx -inkey isat_key.pem -in isat_cert.pem
  Enter Export Password:
  Verifying - Enter Export Password:
  $ ls
  certificate.pfx    isat.pem    isat_cert.pem    isat_key.pem

Now, you have a PXF file.

Important: Do not forget add an exception on the browser in the case the webSocket is set to work with SSL.