🖥️TCP Server

Create a simple transaction server in minutes.

KServerSocket Class Overview

• TLS and Non-TLS Client Connection Support Enables both secure (TLS) and non-secure client connections to server applications, offering flexibility for diverse networking scenarios.

• Client Authentication Supports client authentication using Java KeyStore (JKS) files, providing robust security for sensitive communication.

• Optional TLS Client Authentication Allows server applications to differentiate between authenticated and non-authenticated clients, similar to handling authenticated and non-authenticated HTTP sessions. Use the getAuthenticatedClient() method to verify a valid client name.

• Flexible Data Read/Write Methods Includes efficient methods for reading and writing data in various formats, such as byte[], char[], String, and line-based input.

• Testing TLS Connections macOS/Linux: Use openssl s_client -connect hostname:port

• Testing non-TLS Connections macOS/Linux: Use nc hostname port Windows: Use telnet hostname port

Example Start Echo Server

// Start echo server on port 8080
try (KServerSocket server = New KServerSocket(8080, KSocketServerThreadSample.class)) {
   KLog.abort(!server.isActive(), "Unable to start server: " + server.getLastError());

   // Let client connect (e.g. "nc localhost 8080" or "telnet localhost 8080")
   K.waitMinutes(5);
}

Example Echo Server Server Thread

public class KSocketServerThreadSample extends KSocketServerThread {

   public KSocketServerThreadSample(Socket argSocket) {
      super(argSocket);
   }

   public void run() {
      KLog.info("Upper-Case-Echo-Server started");
      
      String newLine    = K.getLineSeparator();
      String clientData = null;
      
      write((!isSecuredConnection() ? "Non-" : "") + "TLS Upper-Case-Echo-Server ready" + newLine);
      
      while ((clientData = readLine()) != null) {
         write(clientData.toUpperCase() + newLine);
      }
      close();
      
      KLog.info("Upper-Case-Echo-Server terminated");
   }
}

Architecture Overview