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src/kebaagent/Webserver.java

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+/*
+ */
+package kebaagent;
+
+import com.sun.net.httpserver.Headers;
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpHandlers;
+import com.sun.net.httpserver.HttpServer;
+import com.sun.net.httpserver.Request;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.InetSocketAddress;
+import java.util.Optional;
+import java.util.function.Predicate;
+
+
+/**
+ *
+ * @author holz
+ */
+public class Webserver
+{
+
+	private final int port;
+
+	private KebaAgent agent;
+	
+/**
+ * call start()
+ * @see #start() 
+ * @param port 
+ */	
+	public Webserver(int port)
+	{
+		this.port = port;
+	}
+
+	
+/**
+ * Start Webserver
+ * @param agent
+ * @throws IOException 
+ */	
+	public void start(KebaAgent agent) throws IOException
+	{
+		this.agent = agent;
+		
+// Create an HttpServer instance on port 
+		HttpServer server = HttpServer.create(new InetSocketAddress(port), 0);
+		
+		String defaultUri = "/keba";
+		Optional<String> pv = agent.getPropValue("webserver", "defaultUri");
+		if (pv.isPresent())
+			defaultUri = pv.get();
+		
+// Define a context that serves files from the current directory
+//        server.createContext("/", new com.sun.net.httpserver.HttpHandler() 
+//		{
+//            @Override
+//            public void handle(com.sun.net.httpserver.HttpExchange exchange) throws IOException 
+//			{
+//                // Handle requests here (simple file serving)
+//				System.out.println("recvd: " + exchange);
+//// TODO: müsste jetzt die Response generieren. Wie genau, noch nicht nachvollzogen
+		//// ein komplexeres Bsp unter https://dzone.com/articles/simple-http-server-in-java
+		//// Daraus stammt die Klasse MyHttpHandler unten
+//            }
+//        });
+
+
+// andere Variante für Handler am Bsp url http://localhost:8000/t/allowed oder http://localhost:8000/t<irgendwas anderes>
+//		Headers headers = new Headers();
+//		headers.set("Allow", "GET");
+//		headers.set("Content-Type", "text/plain");
+//		
+//		HttpHandler allowedResponse = HttpHandlers.of(200, headers, getBody());		// Statuscode, Headers, body
+
+// Trivialhandler für einfache Antwort
+		HttpHandler deniedResponse = HttpHandlers.of(401, Headers.of("Deny", "GET"), "Denied");
+		
+		JsonHandler allowedResponse = new JsonHandler(agent);
+		
+		
+// welche URL ist erlaubt?
+		final String fDefUri = defaultUri;
+		Predicate<Request> findAllowedPath = r -> 
+//			r.getRequestURI().getPath().equals("/t/allowed");
+			r.getRequestURI().getPath().equals(fDefUri);
+
+		HttpHandler handler = HttpHandlers.handleOrElse(findAllowedPath, allowedResponse, deniedResponse);
+// context ist weiter oben angebunden (ab /t)
+//		server.createContext("/t", handler); 
+		server.createContext(defaultUri, handler); 
+
+// ggf. 2. Handler für / bauen (Infoseite)
+
+		
+// mit MyHttpHandler, ziemlich buggy und unvollständig von https://dzone.com/articles/simple-http-server-in-java 
+//		MyHttpHandler myHandler = new MyHttpHandler(agent);
+//		server.createContext("/m", myHandler);
+		
+		
+        // Start the server
+        server.start();
+        System.out.printf("Server started on port %d\n", port);
+
+		
+	}
+
+	
+//	private String getBody()
+//	{
+//		return "{ 'info': 'hello'}";
+//	}
+//	
+	
+	
+	
+private static class MyHttpHandler implements HttpHandler 
+{    
+
+	private KebaAgent agent;
+	
+		private MyHttpHandler(KebaAgent a)
+		{
+			agent = a;
+		}
+
+/**
+ * zu implementierende Methode
+ * @param httpExchange
+ * @throws IOException 
+ */	
+  @Override    
+  public void handle(HttpExchange httpExchange) throws IOException 
+  {
+		String requestParamValue = null; 
+		System.out.println("MyHttpHandler.handle() httpExchange " + httpExchange);
+		String requestMethod = httpExchange.getRequestMethod();
+		System.out.println("MyHttpHandler.handle().getRequestMethod(): " + requestMethod);
+		if ("GET".equals(httpExchange.getRequestMethod())) 
+		{ 
+		   requestParamValue = handleGetRequest(httpExchange);
+		   System.out.println("MyHttpHandler.handle() GET: requestParamValue = " + requestParamValue);
+		}
+// TODO: nicht im Bsp.
+//	else if("POST".equals(httpExchange)) 
+//	{ 
+//       requestParamValue = handlePostRequest(httpExchange);        
+//    }  
+    handleResponse(httpExchange, requestParamValue); 
+  }
+
+  
+  
+/**
+ * hier hat der Autor Schwachsinn produziert
+ * @param httpExchange
+ * @return 
+ */  
+  private String handleGetRequest(HttpExchange httpExchange) 
+  {
+		String path = httpExchange.getRequestURI().toString();
+
+		try
+		{
+//			return path.split("\\?")[1]
+			return path.split("/")[1]
+//                    .split("=")[1];
+			;
+		} catch (Exception e)
+		{
+			e.printStackTrace();
+			return e.getMessage();
+		}
+   }
+
+  
+  
+   private void handleResponse(HttpExchange httpExchange, String requestParamValue) throws  IOException 
+   {
+		System.out.println("MyHttpHandler.handleResponse ");
+		OutputStream outputStream = httpExchange.getResponseBody();
+		StringBuilder htmlBuilder = new StringBuilder();
+		htmlBuilder
+				.append("<html>")
+				.append("<body>")
+				.append("<h1>")
+				.append("Hello ")
+				.append(requestParamValue)
+				.append("</h1>")
+				.append("</body>")
+				.append("</html>");
+            // encode HTML content 
+// apache commons text + lang
+			try
+			{
+// Schwachsinn: Anwendung auf den ganzen HTML-Code
+//				String htmlResponse = StringEscapeUtils.escapeHtml4(htmlBuilder.toString());
+// So OK
+				String htmlResponse = htmlBuilder.toString();
+				
+// jaho: Header erweitern
+				Headers responseHeaders = httpExchange.getResponseHeaders();
+				responseHeaders.set("Content-Type", "text/plain");
+
+
+// this line is a must (jaho: header senden)
+				httpExchange.sendResponseHeaders(200, htmlResponse.length());
+				
+				
+				outputStream.write(htmlResponse.getBytes());
+				outputStream.flush();
+				outputStream.close();
+		   
+			} catch (Throwable e)
+			{
+				e.printStackTrace();
+			}
+
+
+        }
+   
+} // MyHttpHandler
+	
+	
+	
+}