From 8bb6d12db87f32a77bab14d615f30769d77d9f06 Mon Sep 17 00:00:00 2001
From: Jonathan Lloyd <jonathan@thisisjonathan.com>
Date: Thu, 5 Nov 2020 16:57:20 +0000
Subject: [PATCH 1/2] Return error via SubscriptionListener when presence
 events are malformed

---
 .../client/channel/SubscriptionEventListener.java  | 14 ++++++++++++++
 .../client/channel/impl/PresenceChannelImpl.java   | 13 ++++++++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/pusher/client/channel/SubscriptionEventListener.java b/src/main/java/com/pusher/client/channel/SubscriptionEventListener.java
index 3cecdf94..18bdcca3 100644
--- a/src/main/java/com/pusher/client/channel/SubscriptionEventListener.java
+++ b/src/main/java/com/pusher/client/channel/SubscriptionEventListener.java
@@ -33,4 +33,18 @@ public interface SubscriptionEventListener {
      *            See {@linkplain PusherEvent} for more.
      */
     void onEvent(final PusherEvent event);
+
+    /**
+     * Callback that is fired whenever an unexpected error occurs processing
+     * for this {@linkplain SubscriptionEventListener}.
+     *
+     * @param message
+     *            A description of the problem.
+     * @param e
+     *            An associated exception, if available.
+     */
+    default void onError(String message, Exception e) {
+        // No-op
+        return;
+    };
 }
diff --git a/src/main/java/com/pusher/client/channel/impl/PresenceChannelImpl.java b/src/main/java/com/pusher/client/channel/impl/PresenceChannelImpl.java
index 230adc88..0bc3dbcc 100644
--- a/src/main/java/com/pusher/client/channel/impl/PresenceChannelImpl.java
+++ b/src/main/java/com/pusher/client/channel/impl/PresenceChannelImpl.java
@@ -95,9 +95,20 @@ public String toString() {
 
     @SuppressWarnings({ "rawtypes", "unchecked" })
     private void handleSubscriptionSuccessfulMessage(final String message) {
+        final ChannelEventListener listener = getEventListener();
 
         // extract data from the JSON message
         final PresenceData presenceData = extractPresenceDataFrom(message);
+        if (presenceData == null) {
+            if (listener != null) {
+                listener.onError(
+                    "Subscription failed: Presence data not found",
+                    null
+                );
+            }
+            return;
+        }
+
         final List<String> ids = presenceData.ids;
         final Map<String, Object> hash = presenceData.hash;
 
@@ -109,7 +120,7 @@ private void handleSubscriptionSuccessfulMessage(final String message) {
                 idToUserMap.put(id, user);
             }
         }
-        final ChannelEventListener listener = getEventListener();
+
         if (listener != null) {
             final PresenceChannelEventListener presenceListener = (PresenceChannelEventListener)listener;
             presenceListener.onUsersInformationReceived(getName(), getUsers());

From 8816840e24ba6357778ef3ff0bda00de64c097f5 Mon Sep 17 00:00:00 2001
From: Daniel Browne <daniel.browne@pusher.com>
Date: Thu, 11 Mar 2021 15:00:33 +0000
Subject: [PATCH 2/2] Add test case for subscription error with malformed
 presence event data

---
 .../client/channel/impl/PresenceChannelImplTest.java | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/test/java/com/pusher/client/channel/impl/PresenceChannelImplTest.java b/src/test/java/com/pusher/client/channel/impl/PresenceChannelImplTest.java
index a9c3f96e..8fdc2127 100644
--- a/src/test/java/com/pusher/client/channel/impl/PresenceChannelImplTest.java
+++ b/src/test/java/com/pusher/client/channel/impl/PresenceChannelImplTest.java
@@ -30,6 +30,7 @@ public class PresenceChannelImplTest extends PrivateChannelImplTest {
     private static final String AUTH_RESPONSE = "\"auth\":\"a87fe72c6f36272aa4b1:f9db294eae7\",\"channel_data\":\"{\\\"user_id\\\":\\\"5116a4519575b\\\",\\\"user_info\\\":{\\\"name\\\":\\\"Phil Leggetter\\\",\\\"twitter_id\\\":\\\"@leggetter\\\"}}\"";
     private static final String AUTH_RESPONSE_NUMERIC_ID = "\"auth\":\"a87fe72c6f36272aa4b1:f9db294eae7\",\"channel_data\":\"{\\\"user_id\\\":51169,\\\"user_info\\\":{\\\"name\\\":\\\"Phil Leggetter\\\",\\\"twitter_id\\\":\\\"@leggetter\\\"}}\"";
     private static final String USER_ID = "5116a4519575b";
+    private static final String ERROR_NO_PRESENCE_DATA = "Subscription failed: Presence data not found";
 
     @Mock
     private PresenceChannelEventListener mockEventListener;
@@ -77,6 +78,17 @@ public void testIsSubscribedMethod(){
         assertTrue(channel.isSubscribed());
     }
 
+    @Test
+    public void testInternalSubscriptionSucceededMessageWithNoPresenceDataReturnsError(){
+        final String eventName = "pusher_internal:subscription_succeeded";
+        final Map<String, Object> data = new LinkedHashMap<String, Object>();
+
+        channel.onMessage(eventName, eventJson(eventName, data, getChannelName()));
+
+        final InOrder inOrder = inOrder(mockEventListener);
+        inOrder.verify(mockEventListener).onError(eq(ERROR_NO_PRESENCE_DATA), eq(null));
+    }
+
     @Test
     @Override
     @SuppressWarnings({ "rawtypes", "unchecked" })