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Wrong presence channel behavior (Android/IOS)

オープン
  • 何か問題がありますか？
#299 コメント 2 件 リアクション 2 件 担当者 0 名 GitHub で見る

まだ誰も着手していません。

評価

難易度
3/5
見積もり時間
1〜2日
初心者へのやさしさ
35/100
issue の種類
バグ
明瞭さ
おおむね明確
活発さ
停滞
技術スタック
android, ios, java
領域
mobile-dev

調査の方向性

The problem is in PresenceChannelImpl, in handleSubscriptionSuccessfulMessage, where idToUserMap is filled with put() calls but never cleared before the new user list is applied. Start by reading how idToUserMap is maintained across unsubscribe and resubscribe in PresenceChannelImpl. Done means that after a reconnect, getUsers() reflects only the users in the subscription_succeeded payload, and that a test covers a member leaving while the client was disconnected.

索引モデルが issue の本文から書いたものです。

説明

bug
What is the issue?

Hello there! I found some incorrect behavior of presence channels after restore connection to channel.

Problem step-by-step:

  1. Connect to presence channel two or more users
  2. Go to in background - pusher disconnected
  3. Other users quit from channel
  4. Go to in foreground - pusher connected - we resubscribe to channel
  5. On onUsersInformationReceived we got old data of users in channel

Notate: Swift SDK has workaround with subscribing on "pusher:subscription_succeeded" and process this event separate from flow logic. In Java SDK we don't have such trick...

In PresenceChannelImpl when channel successfully subscribed we got event SUBSCRIPTION_SUCCESS_EVENT = "pusher_internal:subscription_succeeded" with processing in internal channel body and after that call onUsersInformationReceived for self interface.

Problem in idToUserMap map witch need to clear in this case, because if i'm not wrong with SUBSCRIPTION_SUCCESS_EVENT we getting actual data about users in presence channel but in current realisation we lost users who quit from channel while i was unsubscibed.

Debug of this point shown that problem exist - channel got json with 1 user but idToUserMap not cleared and return wrong users data

...

Is it a crash report? Submit stack traces or anything that you think would help
#class PresenceChannelImpl

@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;

        if (ids != null && !ids.isEmpty()) {
            // build the collection of Users
            for (final String id : ids) {
                final String userData = hash.get(id) != null ? GSON.toJson(hash.get(id)) : null;
                final User user = new User(id, userData);
                idToUserMap.put(id, user);  <--- Problem - is not empty. Suggestion: need clear before process users data
            }
        }

        if (listener != null) {
            final PresenceChannelEventListener presenceListener = (PresenceChannelEventListener)listener;
            presenceListener.onUsersInformationReceived(getName(), getUsers());
        }
    }

...

Any improvements you suggest

In this case clear idToUserMap before process users data. I may be wrong, then tell me the correct scenario for working with this type of channels
...

CC @pusher/mobile

主要言語
Java
スター
315
フォーク
140
平均マージ
11日 5時間
マージ済み PR（30日）
4

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  2. 着手することを issue にコメントします — 二人が同じ作業をするのを防げます。
  3. リポジトリをフォークし、ブランチを切って変更します。
  4. issue 番号を参照したプルリクエストを送ります。

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