fix TooManyRequestsException

By using
networkMonitor.isOnline.first()
the function
unregisterNetworkCallback
was triggered, which sometimes causes the ConnectivityManager$TooManyRequestsException.

So each time isOnline.first() was called, the callbackFlow would:
- Register a new NetworkCallback.
- Emit a value and cancel the flow.
- Unregister the NetworkCallback.

The exception was:
Exception android.net.ConnectivityManager$TooManyRequestsException:
  at android.net.ConnectivityManager.convertServiceException (ConnectivityManager.java:3771)
  at android.net.ConnectivityManager.sendRequestForNetwork (ConnectivityManager.java:3960)
  at android.net.ConnectivityManager.sendRequestForNetwork (ConnectivityManager.java:3967)
  at android.net.ConnectivityManager.registerNetworkCallback (ConnectivityManager.java:4349)
  at android.net.ConnectivityManager.registerNetworkCallback (ConnectivityManager.java:4319)
  at com.nextcloud.talk.data.network.NetworkMonitorImpl$isOnline$1.invokeSuspend (NetworkMonitorImpl.kt:61)

To fix this, the cold flow from callbackFlow is converted to a StateFlow.

Signed-off-by: Marcel Hibbe <dev@mhibbe.de>

app/src/main/java/com/nextcloud/talk/adapters/messages/OutcomingTextMessageViewHolder.kt

@@ -134,7 +134,7 @@ class OutcomingTextMessageViewHolder(itemView: View) :
         }
 
         CoroutineScope(Dispatchers.Main).launch {
-            if (message.isTemporary && !networkMonitor.isOnline.first()) {
+            if (message.isTemporary && !networkMonitor.isOnline.value) {
                 updateStatus(
                     R.drawable.ic_signal_wifi_off_white_24dp,
                     context.resources?.getString(R.string.nc_message_offline)

app/src/main/java/com/nextcloud/talk/chat/ChatActivity.kt

@@ -201,7 +201,6 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.collect
-import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -452,7 +451,7 @@ class ChatActivity :
 
         this.lifecycleScope.launch {
             delay(DELAY_TO_SHOW_PROGRESS_BAR)
-            if (adapter?.isEmpty == true && networkMonitor.isOnline.first()) {
+            if (adapter?.isEmpty == true && networkMonitor.isOnline.value) {
                 binding.progressBar.visibility = View.VISIBLE
             }
         }
@@ -927,7 +926,7 @@ class ChatActivity :
             chatViewModel.getGeneralUIFlow.onEach { key ->
                 when (key) {
                     NO_OFFLINE_MESSAGES_FOUND -> {
-                        if (networkMonitor.isOnline.first().not()) {
+                        if (networkMonitor.isOnline.value.not()) {
                             binding.offline.root.visibility = View.VISIBLE
                         }
                     }

app/src/main/java/com/nextcloud/talk/chat/data/network/OfflineFirstChatRepository.kt

@@ -54,7 +54,7 @@ class OfflineFirstChatRepository @Inject constructor(
     private val chatDao: ChatMessagesDao,
     private val chatBlocksDao: ChatBlocksDao,
     private val network: ChatNetworkDataSource,
-    private val monitor: NetworkMonitor,
+    private val networkMonitor: NetworkMonitor,
     userProvider: CurrentUserProviderNew
 ) : ChatMessageRepository {
 
@@ -303,7 +303,7 @@ class OfflineFirstChatRepository @Inject constructor(
             var showUnreadMessagesMarker = true
 
             while (true) {
-                if (!monitor.isOnline.first() || itIsPaused) {
+                if (!networkMonitor.isOnline.value || itIsPaused) {
                     Thread.sleep(HALF_SECOND)
                 } else {
                     // sync database with server
@@ -530,7 +530,7 @@ class OfflineFirstChatRepository @Inject constructor(
     }
 
     private suspend fun sync(bundle: Bundle): List<ChatMessageEntity>? {
-        if (!monitor.isOnline.first()) {
+        if (!networkMonitor.isOnline.value) {
             Log.d(TAG, "Device is offline, can't load chat messages from server")
             return null
         }
@@ -810,7 +810,7 @@ class OfflineFirstChatRepository @Inject constructor(
         sendWithoutNotification: Boolean,
         referenceId: String
     ): Flow<Result<ChatMessage?>> {
-        if (!monitor.isOnline.first()) {
+        if (!networkMonitor.isOnline.value) {
             return flow {
                 emit(Result.failure(IOException("Skipped to send message as device is offline")))
             }

app/src/main/java/com/nextcloud/talk/conversationlist/ConversationsListActivity.kt

@@ -138,7 +138,6 @@ import io.reactivex.disposables.Disposable
 import io.reactivex.schedulers.Schedulers
 import io.reactivex.subjects.BehaviorSubject
 import kotlinx.coroutines.flow.collect
-import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
 import org.apache.commons.lang3.builder.CompareToBuilder
@@ -1359,7 +1358,7 @@ class ConversationsListActivity :
 
     override fun onItemLongClick(position: Int) {
         this.lifecycleScope.launch {
-            if (showShareToScreen || !networkMonitor.isOnline.first()) {
+            if (showShareToScreen || !networkMonitor.isOnline.value) {
                 Log.d(TAG, "sharing to multiple rooms not yet implemented. onItemLongClick is ignored.")
             } else {
                 val clickedItem: Any? = adapter!!.getItem(position)

app/src/main/java/com/nextcloud/talk/conversationlist/data/network/OfflineFirstConversationsRepository.kt

@@ -39,7 +39,7 @@ class OfflineFirstConversationsRepository @Inject constructor(
     private val dao: ConversationsDao,
     private val network: ConversationsNetworkDataSource,
     private val chatNetworkDataSource: ChatNetworkDataSource,
-    private val monitor: NetworkMonitor,
+    private val networkMonitor: NetworkMonitor,
     private val currentUserProviderNew: CurrentUserProviderNew
 ) : OfflineConversationsRepository {
     override val roomListFlow: Flow<List<ConversationModel>>
@@ -58,7 +58,7 @@ class OfflineFirstConversationsRepository @Inject constructor(
             val initialConversationModels = getListOfConversations(user.id!!)
             _roomListFlow.emit(initialConversationModels)
 
-            if (monitor.isOnline.first()) {
+            if (networkMonitor.isOnline.value) {
                 val conversationEntitiesFromSync = getRoomsFromServer()
                 if (!conversationEntitiesFromSync.isNullOrEmpty()) {
                     val conversationModelsFromSync = conversationEntitiesFromSync.map(ConversationEntity::asModel)
@@ -108,7 +108,7 @@ class OfflineFirstConversationsRepository @Inject constructor(
     private suspend fun getRoomsFromServer(): List<ConversationEntity>? {
         var conversationsFromSync: List<ConversationEntity>? = null
 
-        if (!monitor.isOnline.first()) {
+        if (!networkMonitor.isOnline.value) {
             Log.d(TAG, "Device is offline, can't load conversations from server")
             return null
         }

app/src/main/java/com/nextcloud/talk/data/network/NetworkMonitor.kt

@@ -2,13 +2,14 @@
  * Nextcloud Talk - Android Client
  *
  * SPDX-FileCopyrightText: 2024 Julius Linus <juliuslinus1@gmail.com>
+ * SPDX-FileCopyrightText: 2024 Marcel Hibbe <dev@mhibbe.de>
  * SPDX-License-Identifier: GPL-3.0-or-later
  */
 
 package com.nextcloud.talk.data.network
 
 import androidx.lifecycle.LiveData
-import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.StateFlow
 
 /**
  * Utility for reporting app connectivity status.
@@ -17,7 +18,7 @@ interface NetworkMonitor {
     /**
      * Returns the device's current connectivity status.
      */
-    val isOnline: Flow<Boolean>
+    val isOnline: StateFlow<Boolean>
 
     /**
      * Returns the device's current connectivity status as LiveData for better interop with Java code.

app/src/main/java/com/nextcloud/talk/data/network/NetworkMonitorImpl.kt

@@ -2,6 +2,7 @@
  * Nextcloud Talk - Android Client
  *
  * SPDX-FileCopyrightText: 2024 Julius Linus <juliuslinus1@gmail.com>
+ * SPDX-FileCopyrightText: 2024 Marcel Hibbe <dev@mhibbe.de>
  * SPDX-License-Identifier: GPL-3.0-or-later
  */
 
@@ -11,17 +12,17 @@ import android.content.Context
 import android.net.ConnectivityManager
 import android.net.Network
 import android.net.NetworkCapabilities
-import android.net.NetworkRequest.Builder
+import android.util.Log
 import androidx.core.content.getSystemService
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.asLiveData
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.channels.awaitClose
-import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.callbackFlow
-import kotlinx.coroutines.flow.conflate
-import kotlinx.coroutines.flow.distinctUntilChanged
-import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.stateIn
 import javax.inject.Inject
 import javax.inject.Singleton
 
@@ -29,49 +30,57 @@ import javax.inject.Singleton
 class NetworkMonitorImpl @Inject constructor(
     private val context: Context
 ) : NetworkMonitor {
+
+    private val connectivityManager = context.getSystemService<ConnectivityManager>()!!
+
     override val isOnlineLiveData: LiveData<Boolean>
         get() = isOnline.asLiveData()
 
-    override val isOnline: Flow<Boolean> = callbackFlow {
-        val connectivityManager = context.getSystemService<ConnectivityManager>()
-        if (connectivityManager == null) {
-            channel.trySend(false)
-            channel.close()
-            return@callbackFlow
-        }
+    override val isOnline: StateFlow<Boolean> get() = _isOnline
 
-        val networkRequest = Builder()
-            .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
-            .build()
+    private val _isOnline: StateFlow<Boolean> = callbackFlow {
+        val callback = object : ConnectivityManager.NetworkCallback() {
+            override fun onCapabilitiesChanged(network: Network, networkCapabilities: NetworkCapabilities) {
+                super.onCapabilitiesChanged(network, networkCapabilities)
+                val connected = networkCapabilities.hasCapability(
+                    NetworkCapabilities.NET_CAPABILITY_VALIDATED
+                )
+                trySend(connected)
+                Log.d(TAG, "Network status changed: $connected")
+            }
 
-        val networkCallback = object : ConnectivityManager.NetworkCallback() {
-            private val networks = mutableSetOf<Network>()
-
-            override fun onAvailable(network: Network) {
-                networks += network
-                channel.trySend(true)
+            override fun onUnavailable() {
+                super.onUnavailable()
+                trySend(false)
+                Log.d(TAG, "Network status: onUnavailable")
             }
 
             override fun onLost(network: Network) {
-                networks -= network
-                channel.trySend(networks.isNotEmpty())
+                super.onLost(network)
+                trySend(false)
+                Log.d(TAG, "Network status: onLost")
+            }
+
+            override fun onAvailable(network: Network) {
+                super.onAvailable(network)
+                trySend(true)
+                Log.d(TAG, "Network status: onAvailable")
             }
         }
 
-        connectivityManager.registerNetworkCallback(networkRequest, networkCallback)
-
-        channel.trySend(connectivityManager.isCurrentlyConnected())
+        connectivityManager.registerDefaultNetworkCallback(callback)
 
         awaitClose {
-            connectivityManager.unregisterNetworkCallback(networkCallback)
+            connectivityManager.unregisterNetworkCallback(callback)
         }
-    }
-        .distinctUntilChanged()
-        .flowOn(Dispatchers.IO)
-        .conflate()
+    }.stateIn(
+        CoroutineScope(Dispatchers.IO),
+        SharingStarted.WhileSubscribed(COROUTINE_TIMEOUT),
+        false
+    )
 
-    private fun ConnectivityManager.isCurrentlyConnected() =
-        activeNetwork
-            ?.let(::getNetworkCapabilities)
-            ?.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET) ?: false
+    companion object {
+        private val TAG = NetworkMonitorImpl::class.java.simpleName
+        private const val COROUTINE_TIMEOUT = 5000L
+    }
 }

app/src/main/java/com/nextcloud/talk/ui/dialog/MessageActionsDialog.kt

@@ -51,7 +51,6 @@ import io.reactivex.Observer
 import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.disposables.Disposable
 import io.reactivex.schedulers.Schedulers
-import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import java.util.Date
 import javax.inject.Inject
@@ -134,7 +133,7 @@ class MessageActionsDialog(
                         initMenuAddToNote(
                             !message.isDeleted &&
                                 !ConversationUtils.isNoteToSelfConversation(currentConversation) &&
-                                networkMonitor.isOnline.first(),
+                                networkMonitor.isOnline.value,
                             state.roomToken
                         )
                     }
@@ -147,16 +146,16 @@ class MessageActionsDialog(
             }
         }
 
-        initMenuItems()
+        initMenuItems(networkMonitor.isOnline.value)
     }
 
-    private fun initMenuItems() {
+    private fun initMenuItems(isOnline: Boolean) {
         this.lifecycleScope.launch {
             initMenuItemTranslate(
                 !message.isDeleted &&
                     ChatMessage.MessageType.REGULAR_TEXT_MESSAGE == message.getCalculateMessageType() &&
                     CapabilitiesUtil.isTranslationsSupported(spreedCapabilities) &&
-                    networkMonitor.isOnline.first()
+                    isOnline
             )
             initMenuEditorDetails(message.lastEditTimestamp!! != 0L && !message.isDeleted)
             initMenuReplyToMessage(message.replyable && hasChatPermission)
@@ -165,29 +164,29 @@ class MessageActionsDialog(
                     hasUserId(user) &&
                     hasUserActorId(message) &&
                     currentConversation?.type != ConversationEnums.ConversationType.ROOM_TYPE_ONE_TO_ONE_CALL &&
-                    networkMonitor.isOnline.first()
+                    isOnline
             )
             initMenuEditMessage(isMessageEditable)
-            initMenuDeleteMessage(showMessageDeletionButton && networkMonitor.isOnline.first())
+            initMenuDeleteMessage(showMessageDeletionButton && isOnline)
             initMenuForwardMessage(
                 ChatMessage.MessageType.REGULAR_TEXT_MESSAGE == message.getCalculateMessageType() &&
                     !(message.isDeletedCommentMessage || message.isDeleted) &&
-                    networkMonitor.isOnline.first()
+                    isOnline
             )
             initMenuRemindMessage(
                 !message.isDeleted &&
                     hasSpreedFeatureCapability(spreedCapabilities, SpreedFeatures.REMIND_ME_LATER) &&
-                    networkMonitor.isOnline.first()
+                    isOnline
             )
             initMenuMarkAsUnread(
                 message.previousMessageId > NO_PREVIOUS_MESSAGE_ID &&
                     ChatMessage.MessageType.SYSTEM_MESSAGE != message.getCalculateMessageType() &&
-                    networkMonitor.isOnline.first()
+                    isOnline
             )
-            initMenuShare(messageHasFileAttachment || messageHasRegularText && networkMonitor.isOnline.first())
+            initMenuShare(messageHasFileAttachment || messageHasRegularText && isOnline)
             initMenuItemOpenNcApp(
                 ChatMessage.MessageType.SINGLE_NC_ATTACHMENT_MESSAGE == message.getCalculateMessageType() &&
-                    networkMonitor.isOnline.first()
+                    isOnline
             )
             initMenuItemSave(message.getCalculateMessageType() == ChatMessage.MessageType.SINGLE_NC_ATTACHMENT_MESSAGE)
         }

app/src/main/java/com/nextcloud/talk/ui/dialog/TempMessageActionsDialog.kt

@@ -23,7 +23,6 @@ import com.nextcloud.talk.databinding.DialogTempMessageActionsBinding
 import com.nextcloud.talk.ui.theme.ViewThemeUtils
 import com.nextcloud.talk.utils.ApiUtils
 import com.nextcloud.talk.utils.DateUtils
-import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
@@ -59,10 +58,9 @@ class TempMessageActionsDialog(
 
     private fun initMenuItems() {
         this.lifecycleScope.launch {
-            val isOnline = networkMonitor.isOnline.first()
-            initResendMessage(message.sendingFailed && isOnline)
-            initMenuEditMessage(message.sendingFailed || !isOnline)
-            initMenuDeleteMessage(message.sendingFailed || !isOnline)
+            initResendMessage(message.sendingFailed && networkMonitor.isOnline.value)
+            initMenuEditMessage(message.sendingFailed || !networkMonitor.isOnline.value)
+            initMenuDeleteMessage(message.sendingFailed || !networkMonitor.isOnline.value)
             initMenuItemCopy()
         }
     }