java-design-patterns/server-session/src/main/java/com/iluwatar/sessionserver/LogoutHandler.java

package com.iluwatar.sessionserver;

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import java.io.IOException;
import java.io.OutputStream;
import java.time.Instant;
import java.util.Map;
import lombok.extern.slf4j.Slf4j;

/**
 * LogoutHandler.
 */
@Slf4j
public class LogoutHandler implements HttpHandler {

  private Map<String, Integer> sessions;
  private Map<String, Instant> sessionCreationTimes;

  public LogoutHandler(Map<String, Integer> sessions, Map<String, Instant> sessionCreationTimes) {
    this.sessions = sessions;
    this.sessionCreationTimes = sessionCreationTimes;
  }

  @Override
  public void handle(HttpExchange exchange) {
    // Get session ID from cookie
    String sessionId = exchange.getRequestHeaders().getFirst("Cookie").replace("sessionID=", "");
    String currentSessionId = sessions.get(sessionId) == null ? null : sessionId;

    // Send response

    String response = "";
    if (currentSessionId == null) {
      response += "Session has already expired!";
    } else {
      response = "Logout successful!\n" + "Session ID: " + currentSessionId;
    }

    //Remove session
    if (currentSessionId != null) {
      LOGGER.info("User " + sessions.get(currentSessionId) + " deleted!");
    } else {
      LOGGER.info("User already deleted!");
    }
    sessions.remove(sessionId);
    sessionCreationTimes.remove(sessionId);

    try {
      exchange.sendResponseHeaders(200, response.length());
    } catch (IOException e) {
      LOGGER.error("An error has occurred: ", e);
    }

    try (OutputStream os = exchange.getResponseBody()) {
      os.write(response.getBytes());
    } catch (IOException e) {
      LOGGER.error("An error has occurred: ", e);
    }
  }
}