Add metrics.

src/main/java/net/md_5/bungee/BungeeCord.java

@@ -54,7 +54,7 @@ public class BungeeCord {
     /**
      * Current version.
      */
-    private String version = (getClass().getPackage().getImplementationVersion() == null) ? "unknown" : getClass().getPackage().getImplementationVersion();
+    public String version = (getClass().getPackage().getImplementationVersion() == null) ? "unknown" : getClass().getPackage().getImplementationVersion();
     /**
      * Fully qualified connections.
      */
@@ -142,6 +142,8 @@ public class BungeeCord {
 
         saveThread.start();
         $().info("Listening on " + addr);
+
+        new Metrics().start();
     }
 
     /**

src/main/java/net/md_5/bungee/Configuration.java

@@ -13,6 +13,7 @@ import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.UUID;
 import static net.md_5.bungee.Logger.$;
 import net.md_5.bungee.command.CommandSender;
 import net.md_5.bungee.command.ConsoleCommandSender;
@@ -109,6 +110,10 @@ public class Configuration {
      * Maximum number of lines to log before old ones are removed.
      */
     public int logNumLines = 1 << 14;
+    /**
+     * UUID for Metrics.
+     */
+    public String statsUuid = UUID.randomUUID().toString();
 
     /**
      * Load the configuration and save default values.

src/main/java/net/md_5/bungee/Metrics.java

@@ -0,0 +1,129 @@
+package net.md_5.bungee;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.UnsupportedEncodingException;
+import java.net.URL;
+import java.net.URLConnection;
+import java.net.URLEncoder;
+import static net.md_5.bungee.Logger.$;
+
+public class Metrics extends Thread {
+
+    /**
+     * The current revision number
+     */
+    private final static int REVISION = 5;
+    /**
+     * The base url of the metrics domain
+     */
+    private static final String BASE_URL = "http://mcstats.org";
+    /**
+     * The url used to report a server's status
+     */
+    private static final String REPORT_URL = "/report/%s";
+    /**
+     * Interval of time to ping (in minutes)
+     */
+    private final static int PING_INTERVAL = 10;
+
+    public Metrics() {
+        super("Metrics Gathering Thread");
+        setDaemon(true);
+    }
+
+    @Override
+    public void run() {
+        boolean firstPost = true;
+        while (true) {
+            try {
+                // We use the inverse of firstPost because if it is the first time we are posting,
+                // it is not a interval ping, so it evaluates to FALSE
+                // Each time thereafter it will evaluate to TRUE, i.e PING!
+                postPlugin(!firstPost);
+
+                // After the first post we set firstPost to false
+                // Each post thereafter will be a ping
+                firstPost = false;
+            } catch (IOException ex) {
+                $().info("[Metrics] " + ex.getMessage());
+            }
+            try {
+                sleep(PING_INTERVAL * 1000 * 60);
+            } catch (InterruptedException ex) {
+                break;
+            }
+        }
+    }
+
+    /**
+     * Generic method that posts a plugin to the metrics website
+     */
+    private void postPlugin(boolean isPing) throws IOException {
+        // Construct the post data
+        final StringBuilder data = new StringBuilder();
+        data.append(encode("guid")).append('=').append(encode(BungeeCord.instance.config.statsUuid));
+        encodeDataPair(data, "version", BungeeCord.instance.version);
+        encodeDataPair(data, "server", "0");
+        encodeDataPair(data, "players", Integer.toString(BungeeCord.instance.connections.size()));
+        encodeDataPair(data, "revision", String.valueOf(REVISION));
+
+        // If we're pinging, append it
+        if (isPing) {
+            encodeDataPair(data, "ping", "true");
+        }
+
+        // Create the url
+        URL url = new URL(BASE_URL + String.format(REPORT_URL, encode("BungeeCord")));
+
+        // Connect to the website
+        URLConnection connection;
+
+        connection = url.openConnection();
+
+        connection.setDoOutput(true);
+        final BufferedReader reader;
+        final String response;
+        try (OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream())) {
+            writer.write(data.toString());
+            writer.flush();
+            reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
+            response = reader.readLine();
+        }
+        reader.close();
+
+        if (response == null || response.startsWith("ERR")) {
+            throw new IOException(response); //Throw the exception
+        }
+    }
+
+    /**
+     * <p>Encode a key/value data pair to be used in a HTTP post request. This
+     * INCLUDES a & so the first key/value pair MUST be included manually,
+     * e.g:</p>
+     * <code>
+     * StringBuffer data = new StringBuffer();
+     * data.append(encode("guid")).append('=').append(encode(guid));
+     * encodeDataPair(data, "version", description.getVersion());
+     * </code>
+     *
+     * @param buffer the StringBuilder to append the data pair onto
+     * @param key the key value
+     * @param value the value
+     */
+    private static void encodeDataPair(final StringBuilder buffer, final String key, final String value) throws UnsupportedEncodingException {
+        buffer.append('&').append(encode(key)).append('=').append(encode(value));
+    }
+
+    /**
+     * Encode text as UTF-8
+     *
+     * @param text the text to encode
+     * @return the encoded text, as UTF-8
+     */
+    private static String encode(final String text) throws UnsupportedEncodingException {
+        return URLEncoder.encode(text, "UTF-8");
+    }
+}