Request : add some way to retry + introduce RequestExecutor

matrix-sdk-android/src/main/java/im/vector/matrix/android/api/failure/Failure.kt

@@ -5,7 +5,7 @@ import java.io.IOException
 sealed class Failure(cause: Throwable? = null) : Throwable(cause = cause) {
 
     data class Unknown(val throwable: Throwable? = null) : Failure(throwable)
-    data class NetworkConnection(val ioException: IOException) : Failure(ioException)
+    data class NetworkConnection(val ioException: IOException? = null) : Failure(ioException)
     data class ServerError(val error: MatrixError) : Failure(RuntimeException(error.toString()))
 
     abstract class FeatureFailure : Failure()

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/di/NetworkModule.kt

@@ -2,6 +2,7 @@ package im.vector.matrix.android.internal.di
 
 import im.vector.matrix.android.internal.network.AccessTokenInterceptor
 import im.vector.matrix.android.internal.network.NetworkConnectivityChecker
+import im.vector.matrix.android.internal.network.RequestExecutor
 import okhttp3.OkHttpClient
 import okhttp3.logging.HttpLoggingInterceptor
 import org.koin.dsl.context.ModuleDefinition
@@ -50,6 +51,10 @@ class NetworkModule : Module {
             NetworkConnectivityChecker(get())
         }
 
+        single {
+            RequestExecutor(get(), get())
+        }
+
         factory {
             Retrofit.Builder()
                     .client(get())

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/network/Request.kt

@@ -19,7 +19,7 @@ internal inline fun <DATA> executeRequest(block: Request<DATA>.() -> Unit) = Req
 
 internal class Request<DATA> {
 
-    var moshi: Moshi = MoshiProvider.providesMoshi()
+    private val moshi: Moshi = MoshiProvider.providesMoshi()
     lateinit var apiCall: Call<DATA>
 
     fun execute(): Try<DATA> {

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/network/RequestExecutor.kt

@@ -0,0 +1,34 @@
+package im.vector.matrix.android.internal.network
+
+import arrow.core.Try
+import im.vector.matrix.android.api.failure.Failure
+import im.vector.matrix.android.internal.util.MatrixCoroutineDispatchers
+import im.vector.matrix.android.internal.util.retry
+import kotlinx.coroutines.withContext
+
+internal class RequestExecutor(private val networkConnectivityChecker: NetworkConnectivityChecker,
+                               private val coroutineDispatchers: MatrixCoroutineDispatchers) {
+
+
+    suspend fun <T> execute(retryTimes: Int = Int.MAX_VALUE,
+                            initialDelay: Long = 100,
+                            maxDelay: Long = 10_000,
+                            factor: Double = 2.0,
+                            block: suspend () -> Try<T>): Try<T> = withContext(coroutineDispatchers.io) {
+
+        retry(retryTimes, initialDelay, maxDelay, factor) {
+            executeIfConnected { block() }
+        }
+
+    }
+
+    private suspend fun <T> executeIfConnected(block: suspend () -> Try<T>): Try<T> {
+        return if (networkConnectivityChecker.isConnected()) {
+            block()
+        } else {
+            Try.raise(Failure.NetworkConnection())
+        }
+    }
+
+
+}

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/group/GetGroupDataRequest.kt

@@ -9,6 +9,7 @@ import im.vector.matrix.android.api.MatrixCallback
 import im.vector.matrix.android.api.util.Cancelable
 import im.vector.matrix.android.internal.database.model.GroupSummaryEntity
 import im.vector.matrix.android.internal.database.query.where
+import im.vector.matrix.android.internal.network.RequestExecutor
 import im.vector.matrix.android.internal.network.executeRequest
 import im.vector.matrix.android.internal.session.group.model.GroupRooms
 import im.vector.matrix.android.internal.session.group.model.GroupSummaryResponse
@@ -19,26 +20,27 @@ import im.vector.matrix.android.internal.util.tryTransactionSync
 import io.realm.kotlin.createObject
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
 
 internal class GetGroupDataRequest(
         private val groupAPI: GroupAPI,
         private val monarchy: Monarchy,
-        private val coroutineDispatchers: MatrixCoroutineDispatchers
+        private val coroutineDispatchers: MatrixCoroutineDispatchers,
+        private val requestExecutor: RequestExecutor
 ) {
 
     fun execute(groupId: String,
                 callback: MatrixCallback<Boolean>
     ): Cancelable {
         val job = GlobalScope.launch(coroutineDispatchers.main) {
-            val groupOrFailure = execute(groupId)
+            val groupOrFailure = requestExecutor.execute { getGroupData(groupId) }
             groupOrFailure.fold({ callback.onFailure(it) }, { callback.onSuccess(true) })
         }
         return CancelableCoroutine(job)
     }
 
-    private suspend fun execute(groupId: String) = withContext(coroutineDispatchers.io) {
-        Try.monad().binding {
+    private fun getGroupData(groupId: String): Try<Unit> {
+        return Try.monad().binding {
+
             val groupSummary = executeRequest<GroupSummaryResponse> {
                 apiCall = groupAPI.getSummary(groupId)
             }.bind()
@@ -50,6 +52,7 @@ internal class GetGroupDataRequest(
             val groupUsers = executeRequest<GroupUsers> {
                 apiCall = groupAPI.getUsers(groupId)
             }.bind()
+
             insertInDb(groupSummary, groupRooms, groupUsers, groupId).bind()
         }.fix()
     }
@@ -61,7 +64,7 @@ internal class GetGroupDataRequest(
         return monarchy
                 .tryTransactionSync { realm ->
                     val groupSummaryEntity = GroupSummaryEntity.where(realm, groupId).findFirst()
-                            ?: realm.createObject(groupId)
+                                             ?: realm.createObject(groupId)
 
                     groupSummaryEntity.avatarUrl = groupSummary.profile?.avatarUrl ?: ""
                     val name = groupSummary.profile?.name

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/group/GroupModule.kt

@@ -16,7 +16,7 @@ class GroupModule : Module {
         }
 
         scope(DefaultSession.SCOPE) {
-            GetGroupDataRequest(get(), get(), get())
+            GetGroupDataRequest(get(), get(), get(), get())
         }
 
     }.invoke()

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/util/CoroutineRetry.kt

@@ -0,0 +1,24 @@
+package im.vector.matrix.android.internal.util
+
+import arrow.core.Try
+import kotlinx.coroutines.delay
+
+suspend fun <T> retry(
+        times: Int = Int.MAX_VALUE,
+        initialDelay: Long = 100, // 0.1 second
+        maxDelay: Long = 10_000,    // 10 second
+        factor: Double = 2.0,
+        block: suspend () -> Try<T>): Try<T> {
+
+    var currentDelay = initialDelay
+    repeat(times - 1) {
+        val blockResult = block()
+        if (blockResult.isSuccess()) {
+            return blockResult
+        } else {
+            delay(currentDelay)
+            currentDelay = (currentDelay * factor).toLong().coerceAtMost(maxDelay)
+        }
+    }
+    return block()
+}