Allow reconnection from same user if device is not active (#210)

Author: devgianlu

api/src/main/java/xyz/gianlu/librespot/api/SessionWrapper.java

@@ -65,7 +65,7 @@ private void clear() {
     public Session get() {
         Session s = ref.get();
         if (s != null) {
-            if (s.valid()) return s;
+            if (s.isValid()) return s;
             else clear();
         }
 

api/src/main/java/xyz/gianlu/librespot/api/handlers/AbsSessionHandler.java

@@ -3,7 +3,6 @@
 import io.undertow.server.HttpHandler;
 import io.undertow.server.HttpServerExchange;
 import io.undertow.util.Headers;
-import io.undertow.util.HttpString;
 import io.undertow.util.StatusCodes;
 import org.jetbrains.annotations.NotNull;
 import xyz.gianlu.librespot.api.SessionWrapper;
@@ -33,7 +32,7 @@ public final void handleRequest(HttpServerExchange exchange) throws Exception {
             return;
         }
 
-        if (!s.valid()) {
+        if (!s.isValid()) {
             exchange.setStatusCode(StatusCodes.INTERNAL_SERVER_ERROR);
             return;
         }

core/src/main/java/xyz/gianlu/librespot/connectstate/DeviceStateHandler.java

@@ -180,7 +180,7 @@ private synchronized long startedPlayingAt() {
         return putState.getStartedPlayingAt();
     }
 
-    private synchronized boolean isActive() {
+    public synchronized boolean isActive() {
         return putState.getIsActive();
     }
 

core/src/main/java/xyz/gianlu/librespot/core/Session.java

@@ -603,7 +603,11 @@ public Authentication.APWelcome apWelcome() {
         return apWelcome;
     }
 
-    public boolean valid() {
+    public boolean isActive() {
+        return player().isActive();
+    }
+
+    public boolean isValid() {
         if (closed) return false;
 
         waitAuthLock();

core/src/main/java/xyz/gianlu/librespot/core/ZeroconfServer.java

@@ -31,6 +31,7 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.TimeUnit;
 
 /**
  * @author Gianlu
@@ -94,6 +95,7 @@ public class ZeroconfServer implements Closeable {
     private final List<SessionListener> sessionListeners;
     private final Zeroconf zeroconf;
     private volatile Session session;
+    private volatile long connectionTime;
 
     private ZeroconfServer(Session.Inner inner, Configuration conf) throws IOException {
         this.inner = inner;
@@ -214,17 +216,24 @@ public void close() throws IOException {
 
     public void closeSession() throws IOException {
         if (session != null) session.close();
+
+        session = null;
+        connectionTime = 0;
     }
 
-    public boolean hasValidSession() {
-        boolean valid = session != null && session.valid();
-        if (!valid) session = null;
+    private boolean hasActiveSession() {
+        boolean valid = session != null && session.isValid() && session.isActive();
+        if (!valid) {
+            session = null;
+            connectionTime = 0;
+        }
+
         return valid;
     }
 
     private void handleGetInfo(OutputStream out, String httpVersion) throws IOException {
         JsonObject info = DEFAULT_GET_INFO_FIELDS.deepCopy();
-        info.addProperty("activeUser", hasValidSession() ? session.username() : "");
+        info.addProperty("activeUser", hasActiveSession() ? session.username() : "");
         info.addProperty("deviceID", inner.deviceId);
         info.addProperty("remoteName", inner.deviceName);
         info.addProperty("publicKey", Base64.getEncoder().encodeToString(keys.publicKeyArray()));
@@ -263,14 +272,13 @@ private void handleAddUser(OutputStream out, Map<String, String> params, String
             return;
         }
 
-        if (hasValidSession()) {
+        if (hasActiveSession() && System.currentTimeMillis() - connectionTime > TimeUnit.SECONDS.toMillis(60)) {
             if (session.username().equals(username)) {
                 LOGGER.debug(String.format("Dropped connection attempt because user is already connected. {username: %s}", session.username()));
-                return;
+            } else {
+                session.close();
+                LOGGER.trace(String.format("Closed previous session to accept new. {deviceId: %s}", session.deviceId()));
             }
-
-            session.close();
-            LOGGER.trace(String.format("Closed previous session to accept new. {deviceId: %s}", session.deviceId()));
         }
 
         byte[] sharedKey = Utils.toByteArray(keys.computeSharedKey(Base64.getDecoder().decode(clientKeyStr)));
@@ -326,6 +334,7 @@ private void handleAddUser(OutputStream out, Map<String, String> params, String
             Authentication.LoginCredentials credentials = inner.decryptBlob(username, decrypted);
 
             session = Session.from(inner);
+            connectionTime = System.currentTimeMillis();
             LOGGER.info(String.format("Accepted new user from %s. {deviceId: %s}", params.get("deviceName"), session.deviceId()));
 
             session.connect();
@@ -429,7 +438,7 @@ private void handle(@NotNull Socket socket) throws IOException {
                 headers.put(split[0], split[1].trim());
             }
 
-            if (!hasValidSession())
+            if (!hasActiveSession())
                 LOGGER.trace(String.format("Handling request: %s %s %s, headers: %s", method, path, httpVersion, headers));
 
             Map<String, String> params;

core/src/main/java/xyz/gianlu/librespot/player/Player.java

@@ -722,6 +722,13 @@ public long time() {
         }
     }
 
+    /**
+     * @return Whether the player is active
+     */
+    public boolean isActive() {
+        return state.isActive();
+    }
+
     public interface Configuration {
         @NotNull
         AudioQuality preferredQuality();

core/src/main/java/xyz/gianlu/librespot/player/StateWrapper.java

@@ -100,6 +100,10 @@ private boolean shouldPlay(@NotNull ContextTrack track) {
         return !Boolean.parseBoolean(track.getMetadataOrDefault("is_explicit", "false"));
     }
 
+    boolean isActive() {
+        return device.isActive();
+    }
+
     void setBuffering(boolean buffering) {
         setState(state.getIsPlaying(), state.getIsPaused(), buffering);
     }