implemented Server Sent events and Heartbeat

resources/js/plan.js

@@ -158,4 +158,8 @@ window.onload = function () {
 	$('.menu .move .list div').click(enableMove);
 	$('.menu .actions .list > div').click(runAction);
 	$(BODY).click(bodyClick);
+	var stream = new EventSource("stream");
+	stream.onmessage = function(ev){
+		console.log(ev);
+	}
 }

src/main/java/de/srsoftware/web4rail/Application.java

@@ -6,6 +6,7 @@ import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.io.OutputStreamWriter;
 import java.lang.reflect.InvocationTargetException;
 import java.net.InetSocketAddress;
 import java.net.URI;
@@ -38,6 +39,7 @@ public class Application {
 		server.createContext("/plan", client -> sendPlan(client));
 		server.createContext("/css" , client -> sendFile(client));
 		server.createContext("/js" , client -> sendFile(client));
+		server.createContext("/stream", client -> stream(client));
         server.setExecutor(java.util.concurrent.Executors.newCachedThreadPool());
         server.start();
         try {
@@ -48,35 +50,6 @@ public class Application {
         Desktop.getDesktop().browse(URI.create("http://localhost:"+config.getInt(PORT)+"/plan"));
 	}
 	
-	private static void sendFile(HttpExchange client) throws IOException {
-		URI uri = client.getRequestURI();
-		File file = new File(System.getProperty("user.dir")+"/resources"+uri);
-		LOG.debug("requesting file: {}",file);
-		if (file.exists()) {
-			client.getResponseHeaders().add("Content-Type", Files.probeContentType(file.toPath()));
-			client.sendResponseHeaders(200, file.length());
-			OutputStream out = client.getResponseBody();
-			FileInputStream in = new FileInputStream(file);
-			in.transferTo(out);
-			in.close();
-			out.close();
-			return;
-		}
-		sendError(client,404,t("Could not find \"{}\"",uri));
-	}
-
-	private static void sendError(HttpExchange client, int code, String msg) throws IOException {
-		client.sendResponseHeaders(code, msg.length());
-		LOG.error(msg);
-		OutputStream out = client.getResponseBody();
-		out.write(msg.getBytes(UTF8));
-		out.close();
-	}
-
-	private static HashMap<String, String> inflate(byte[] data) {
-		return inflate(new String(data,UTF8));
-	}
-
 	private static HashMap<String, String> inflate(String data) {
 		LOG.debug("inflate({})",data);
 		HashMap<String, String> params = new HashMap<String, String>();
@@ -91,6 +64,10 @@ public class Application {
 		return params;
 	}	
 
+	private static HashMap<String, String> inflate(byte[] data) {
+		return inflate(new String(data,UTF8));
+	}
+	
 	private static void send(HttpExchange client, Object response) throws IOException {
 		byte[] html;
 		if (response instanceof Page) {
@@ -107,6 +84,31 @@ public class Application {
         os.close();
 	}
 
+	private static void sendError(HttpExchange client, int code, String msg) throws IOException {
+		client.sendResponseHeaders(code, msg.length());
+		LOG.error(msg);
+		OutputStream out = client.getResponseBody();
+		out.write(msg.getBytes(UTF8));
+		out.close();
+	}
+
+	private static void sendFile(HttpExchange client) throws IOException {
+		URI uri = client.getRequestURI();
+		File file = new File(System.getProperty("user.dir")+"/resources"+uri);
+		LOG.debug("requesting file: {}",file);
+		if (file.exists()) {
+			client.getResponseHeaders().add("Content-Type", Files.probeContentType(file.toPath()));
+			client.sendResponseHeaders(200, file.length());
+			OutputStream out = client.getResponseBody();
+			FileInputStream in = new FileInputStream(file);
+			in.transferTo(out);
+			in.close();
+			out.close();
+			return;
+		}
+		sendError(client,404,t("Could not find \"{}\"",uri));
+	}
+	
 	private static void sendPlan(HttpExchange client) throws IOException {
 		try {
 			HashMap<String, String> params = inflate(client.getRequestBody().readAllBytes());
@@ -117,6 +119,13 @@ public class Application {
 		}		
 	}
 	
+	private static void stream(HttpExchange client) throws IOException {
+		client.getResponseHeaders().set("content-type", "text/event-stream");
+		client.sendResponseHeaders(200, 0);
+		OutputStreamWriter sseWriter = new OutputStreamWriter(client.getResponseBody());
+		plan.addClient(sseWriter);
+	}
+	
 	private static String t(String text, Object...fills) {
 		return Translation.get(Application.class, text, fills);
 	}

src/main/java/de/srsoftware/web4rail/Plan.java

@@ -6,9 +6,11 @@ import java.io.File;
 import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.IOException;
+import java.io.OutputStreamWriter;
 import java.lang.reflect.InvocationTargetException;
 import java.security.InvalidParameterException;
 import java.util.Collection;
+import java.util.Date;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -62,6 +64,21 @@ public class Plan {
 	public enum Direction{		
 		NORTH, SOUTH, EAST, WEST
 	}
+	
+	private class Heartbeat extends Thread {
+		@Override
+		public void run() {			
+			try {
+				while (true) {
+					sleep(10000);
+					heatbeat();
+				}
+			} catch (InterruptedException e) {
+				e.printStackTrace();
+			}
+		}
+	}
+	
 	private static final String ACTION = "action";
 	private static final String ACTION_ADD = "add";
 	private static final String ACTION_ANALYZE = "analyze";
@@ -78,11 +95,47 @@ public class Plan {
 	private static final String ACTION_ROUTE = "openRoute";
 	private static final String ID = "id";
 	private static final String ROUTE = "route";
+	private static final HashMap<OutputStreamWriter,Integer> clients = new HashMap<OutputStreamWriter, Integer>();
 	
 	private HashMap<Integer,HashMap<Integer,Tile>> tiles = new HashMap<Integer,HashMap<Integer,Tile>>();
 	private HashSet<Block> blocks = new HashSet<Block>();
 	private HashMap<String, Route> routes = new HashMap<String, Route>();
 	
+	public Plan() {
+		new Heartbeat().start();
+	}
+	
+	public void heatbeat() {
+		stream("hearbeat @ "+new Date().getTime());
+	}
+
+	private void stream(String data) {
+		LOG.debug("streaming {}",data);
+		Vector<OutputStreamWriter> badClients = null;
+		for (Entry<OutputStreamWriter, Integer> entry : clients.entrySet()) {
+			OutputStreamWriter client = entry.getKey();
+			try {
+				client.write("data: "+data+"\n\n");
+				client.flush();
+				clients.put(client,0);
+			} catch (IOException e) {
+				int errorCount = entry.getValue()+1;
+				LOG.info("Error #{} on client: {}",errorCount,e.getMessage());
+				if (errorCount > 4) {
+					if (badClients == null) badClients = new Vector<OutputStreamWriter>();
+					try {
+						client.close();
+					} catch (IOException e1) {}
+					badClients.add(client);
+				} else clients.put(client,errorCount);
+			}
+		}
+		if (badClients != null) for (OutputStreamWriter client: badClients) {
+			LOG.info("Disconnecting client.");
+			clients.remove(client);			
+		}
+	}
+
 	private Tag actionMenu() throws IOException {
 		Tag tileMenu = new Tag("div").clazz("actions").content(t("Actions"));		
 		StringBuffer tiles = new StringBuffer();
@@ -91,6 +144,11 @@ public class Plan {
 		return new Tag("div").clazz("list").content(tiles.toString()).addTo(tileMenu);
 	}
 	
+	public void addClient(OutputStreamWriter client) {
+		LOG.debug("Client connected.");
+		clients.put(client, 0);
+	}
+	
 	public static void addLink(Tile tile,String content,Tag list) {
 		new Tag("li").clazz("link").attr("onclick", "return clickTile("+tile.x+","+tile.y+");").content(content).addTo(list);
 	}
@@ -187,7 +245,7 @@ public class Plan {
 				String line = br.readLine().trim();
 				String[] parts = line.split("=",2);
 				try {
-					String id = parts[0];
+					//String id = parts[0];
 					JSONObject json = new JSONObject(parts[1]);
 					Route route = new Route();
 					json.getJSONArray(Route.PATH).forEach(entry -> {