add ping and pong events

src/main/java/io/socket/client/Manager.java

@@ -64,6 +64,10 @@ public class Manager extends Emitter {
 
     public static final String EVENT_RECONNECTING = "reconnecting";
 
+    public static final String EVENT_PING = "ping";
+
+    public static final String EVENT_PONG = "pong";
+
     /**
      * Called when a new transport is created. (experimental)
      */
@@ -85,6 +89,7 @@ public class Manager extends Emitter {
     private Backoff backoff;
     private long _timeout;
     private Set<Socket> connecting = new HashSet<Socket>();
+    private Date lastPing;
     private URI uri;
     private List<Packet> packetBuffer;
     private Queue<On.Handle> subs;
@@ -348,10 +353,16 @@ public class Manager extends Emitter {
                 }
             }
         }));
-        this.subs.add(On.on(this.decoder, Parser.Decoder.EVENT_DECODED, new Listener() {
+        this.subs.add(On.on(socket, Engine.EVENT_PING, new Listener() {
             @Override
             public void call(Object... objects) {
-                Manager.this.ondecoded((Packet) objects[0]);
+                Manager.this.onping();
+            }
+        }));
+        this.subs.add(On.on(socket, Engine.EVENT_PONG, new Listener() {
+            @Override
+            public void call(Object... objects) {
+                Manager.this.onpong();
             }
         }));
         this.subs.add(On.on(socket, Engine.EVENT_ERROR, new Listener() {
@@ -366,6 +377,22 @@ public class Manager extends Emitter {
                 Manager.this.onclose((String)objects[0]);
             }
         }));
+        this.subs.add(On.on(this.decoder, Parser.Decoder.EVENT_DECODED, new Listener() {
+            @Override
+            public void call(Object... objects) {
+                Manager.this.ondecoded((Packet) objects[0]);
+            }
+        }));
+    }
+
+    private void onping() {
+        this.lastPing = new Date();
+        this.emitAll(EVENT_PING);
+    }
+
+    private void onpong() {
+        this.emitAll(EVENT_PONG,
+                null != this.lastPing ? new Date().getTime() - this.lastPing.getTime() : 0);
     }
 
     private void ondata(String data) {
@@ -458,8 +485,12 @@ public class Manager extends Emitter {
     }
 
     private void cleanup() {
+        logger.fine("cleanup");
+
         On.Handle sub;
         while ((sub = this.subs.poll()) != null) sub.destroy();
+
+        this.lastPing = null;
     }
 
     /*package*/ void close() {

src/main/java/io/socket/client/Socket.java

@@ -58,6 +58,10 @@ public class Socket extends Emitter {
 
     public static final String EVENT_RECONNECTING = Manager.EVENT_RECONNECTING;
 
+    public static final String EVENT_PING = Manager.EVENT_PING;
+
+    public static final String EVENT_PONG = Manager.EVENT_PONG;
+
     protected static Map<String, Integer> events = new HashMap<String, Integer>() {{
         put(EVENT_CONNECT, 1);
         put(EVENT_CONNECT_ERROR, 1);
@@ -70,6 +74,8 @@ public class Socket extends Emitter {
         put(EVENT_RECONNECT_FAILED, 1);
         put(EVENT_RECONNECT_ERROR, 1);
         put(EVENT_RECONNECTING, 1);
+        put(EVENT_PING, 1);
+        put(EVENT_PONG, 1);
     }};
 
     /*package*/ String id;

src/test/java/io/socket/client/SocketTest.java

@@ -11,6 +11,7 @@ import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.LinkedBlockingQueue;
 
 import static org.hamcrest.CoreMatchers.*;
+import static org.hamcrest.Matchers.greaterThan;
 import static org.junit.Assert.assertThat;
 
 @RunWith(JUnit4.class)
@@ -60,6 +61,43 @@ public class SocketTest extends Connection {
         assertThat(id.isPresent(), is(false));
     }
 
+    @Test(timeout = TIMEOUT)
+    public void pingAndPongWithLatency() throws URISyntaxException, InterruptedException {
+        final BlockingQueue<Object> values = new LinkedBlockingQueue<Object>();
+        socket = client();
+        socket.on(Socket.EVENT_CONNECT, new Emitter.Listener() {
+            @Override
+            public void call(Object... objects) {
+                final boolean[] pinged = new boolean[] { false };
+                socket.once(Socket.EVENT_PING, new Emitter.Listener() {
+                    @Override
+                    public void call(Object... args) {
+                        pinged[0] = true;
+                    }
+                });
+                socket.once(Socket.EVENT_PONG, new Emitter.Listener() {
+                    @Override
+                    public void call(Object... args) {
+                        long ms = (long)args[0];
+                        values.offer(pinged[0]);
+                        values.offer(ms);
+                    }
+                });
+            }
+        });
+        socket.connect();
+
+        @SuppressWarnings("unchecked")
+        boolean pinged = (boolean)values.take();
+        assertThat(pinged, is(true));
+
+        @SuppressWarnings("unchecked")
+        long ms = (long)values.take();
+        assertThat(ms, greaterThan((long)0));
+
+        socket.disconnect();
+    }
+
     @Test(timeout = TIMEOUT)
     public void shouldChangeSocketIdUponReconnection() throws URISyntaxException, InterruptedException {
         final BlockingQueue<Optional> values = new LinkedBlockingQueue<Optional>();

src/test/resources/server.js

@@ -10,7 +10,7 @@ if (process.env.SSL) {
   server = require('http').createServer();
 }
 
-var io = require('socket.io')(server);
+var io = require('socket.io')(server, { pingInterval: 2000 });
 var port = process.env.PORT || 3000;
 var nsp = process.argv[2] || '/';
 var slice = Array.prototype.slice;