Merge pull request #63 from swapnil-musale/response_handling

Improvement in Network Layer Response Handling

.gitignore

@@ -13,3 +13,4 @@
 .externalNativeBuild
 .cxx
 local.properties
+deploymentTargetDropDown.xml

app/src/main/java/com/devx/jetjoke/ui/home/HomeScreen.kt

@@ -1,7 +1,6 @@
 package com.devx.jetjoke.ui.home
 
 import androidx.compose.animation.AnimatedContent
-import androidx.compose.animation.ExperimentalAnimationApi
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
@@ -41,10 +40,9 @@ import com.devx.jetjoke.ui.home.component.JokeCategoryTag
 import com.devx.jetjoke.ui.home.component.TypewriterText
 import com.devx.jetjoke.ui.shimmer.JokeShimmerItem
 
-@OptIn(ExperimentalAnimationApi::class)
 @Composable
 fun HomeScreen(
-    uiState: HomeScreenState,
+    uiState: HomeScreenUiState,
     loadNextJoke: () -> Unit,
 ) {
     var displayJoke by remember { mutableStateOf("") }
@@ -127,7 +125,7 @@ fun HomeScreen(
 private fun HomeScreenPreview() {
     JetJokeTheme {
         HomeScreen(
-            uiState = HomeScreenState(
+            uiState = HomeScreenUiState(
                 isLoading = false,
                 jokeData = getFakeJokeData(),
             ),

app/src/main/java/com/devx/jetjoke/ui/home/HomeScreenState.kt → app/src/main/java/com/devx/jetjoke/ui/home/HomeScreenUiState.kt

@@ -2,7 +2,8 @@ package com.devx.jetjoke.ui.home
 
 import com.devx.domain.model.JokeResponse
 
-data class HomeScreenState(
+data class HomeScreenUiState(
     val isLoading: Boolean = false,
     val jokeData: JokeResponse? = null,
+    val errorMessage: String? = null,
 )

app/src/main/java/com/devx/jetjoke/ui/home/HomeViewModel.kt

@@ -3,6 +3,7 @@ package com.devx.jetjoke.ui.home
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.devx.domain.useCase.GetJokeUseCase
+import com.devx.domain.util.NetworkResponse
 import com.devx.jetjoke.util.DispatchersProvider
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -18,9 +19,9 @@ class HomeViewModel @Inject constructor(
     private val dispatchersProvider: DispatchersProvider,
 ) : ViewModel() {
 
-    private val _uiState: MutableStateFlow<HomeScreenState> =
-        MutableStateFlow(value = HomeScreenState())
-    val uiState: StateFlow<HomeScreenState> = _uiState.asStateFlow()
+    private val _uiState: MutableStateFlow<HomeScreenUiState> =
+        MutableStateFlow(value = HomeScreenUiState())
+    val uiState: StateFlow<HomeScreenUiState> = _uiState.asStateFlow()
 
     init {
         fetchJoke()
@@ -31,13 +32,25 @@ class HomeViewModel @Inject constructor(
             _uiState.update {
                 it.copy(isLoading = true)
             }
-            val response = getJokeUseCase()
-            if (response.error?.not() == true) {
-                _uiState.update {
-                    it.copy(
-                        isLoading = false,
-                        jokeData = response,
-                    )
+            when (val response = getJokeUseCase()) {
+                is NetworkResponse.Success -> {
+                    _uiState.update {
+                        it.copy(
+                            isLoading = false,
+                            jokeData = response.data,
+                        )
+                    }
+                }
+
+                is NetworkResponse.Error -> {
+                    // TODO Show Snack bar
+                    _uiState.update {
+                        it.copy(isLoading = false, errorMessage = response.errorMessage)
+                    }
+                }
+
+                is NetworkResponse.Exception -> {
+                    // TODO Show Snack bar
                 }
             }
         }

data/src/main/java/com/devx/data/JokeApi.kt

@@ -1,11 +1,11 @@
 package com.devx.data
 
-import com.devx.data.model.JokeResponse
+import com.devx.data.model.JokeResponseDto
 import retrofit2.Response
 import retrofit2.http.GET
 
 interface JokeApi {
 
     @GET("joke/Any")
-    suspend fun getJoke(): Response<JokeResponse>
+    suspend fun getJoke(): Response<JokeResponseDto>
 }

data/src/main/java/com/devx/data/model/JokeResponse.kt → data/src/main/java/com/devx/data/model/JokeResponseDto.kt

@@ -1,10 +1,12 @@
 package com.devx.data.model
 
 import androidx.annotation.Keep
+import com.devx.domain.model.JokeResponse
+import com.devx.domain.util.Mapper
 import com.squareup.moshi.Json
 
 @Keep
-data class JokeResponse(
+data class JokeResponseDto(
 
     @field:Json(name = "delivery")
     val delivery: String? = null,
@@ -35,4 +37,16 @@ data class JokeResponse(
 
     @field:Json(name = "message")
     val message: String? = null,
-)
+) : Mapper<JokeResponse> {
+    override fun mapToDomain(): JokeResponse {
+        return JokeResponse(
+            error = error ?: false,
+            type = type.orEmpty(),
+            setUp = setup,
+            joke = joke,
+            delivery = delivery,
+            category = category.orEmpty(),
+            message = message,
+        )
+    }
+}

data/src/main/java/com/devx/data/repository/JokeRepositoryImpl.kt

@@ -1,32 +1,20 @@
 package com.devx.data.repository
 
 import com.devx.data.JokeApi
-import com.devx.data.mapper.toDto
 import com.devx.data.model.JokeCategoryData
+import com.devx.data.util.safeApiCall
 import com.devx.domain.model.JokeResponse
 import com.devx.domain.repository.JokeRepository
+import com.devx.domain.util.NetworkResponse
 import javax.inject.Inject
 
 class JokeRepositoryImpl @Inject constructor(private val jokeApi: JokeApi) : JokeRepository {
 
-    override suspend fun getJoke(): JokeResponse {
-        return try {
-            val response = jokeApi.getJoke()
-            response.body().toDto()
-        } catch (exception: Exception) {
-            JokeResponse(
-                joke = "",
-                setUp = "",
-                delivery = "",
-                category = "",
-                type = "",
-                error = true,
-                message = exception.message,
-            )
-        }
+    override suspend fun getJoke(): NetworkResponse<JokeResponse> {
+        return safeApiCall { jokeApi.getJoke() }
     }
 
-    override fun getJokeCategories(): ArrayList<String> {
-        return JokeCategoryData.jokeCategories
+    override fun getJokeCategories(): NetworkResponse<List<String>> {
+        return NetworkResponse.Success(data = JokeCategoryData.jokeCategories)
     }
 }

data/src/main/java/com/devx/data/util/NetworkUtil.kt

@@ -0,0 +1,22 @@
+package com.devx.data.util
+
+import com.devx.domain.util.Mapper
+import com.devx.domain.util.NetworkResponse
+import retrofit2.HttpException
+import retrofit2.Response
+
+suspend fun <R : Mapper<T>, T : Any> safeApiCall(execute: suspend () -> Response<R>): NetworkResponse<T> {
+    return try {
+        val response = execute()
+        val body = response.body()
+        if (response.isSuccessful && body != null) {
+            NetworkResponse.Success(data = body.mapToDomain())
+        } else {
+            NetworkResponse.Error(errorMessage = response.message())
+        }
+    } catch (exception: HttpException) {
+        NetworkResponse.Error(errorMessage = exception.localizedMessage)
+    } catch (throwable: Throwable) {
+        NetworkResponse.Exception(throwable = throwable)
+    }
+}

domain/src/main/java/com/devx/domain/model/JokeResponse.kt

@@ -13,7 +13,7 @@ data class JokeResponse(
 fun getFakeJokeData(): JokeResponse {
     return JokeResponse(
         error = false,
-        type = "twopart", // "single"
+        type = "twopart",
         setUp = "So what's a set of predefined steps the government might take to preserve the environment?",
         delivery = "An Al-Gore-ithm.",
         category = "Programming",

domain/src/main/java/com/devx/domain/repository/JokeRepository.kt

@@ -1,8 +1,9 @@
 package com.devx.domain.repository
 
 import com.devx.domain.model.JokeResponse
+import com.devx.domain.util.NetworkResponse
 
 interface JokeRepository {
-    suspend fun getJoke(): JokeResponse
-    fun getJokeCategories(): ArrayList<String>
+    suspend fun getJoke(): NetworkResponse<JokeResponse>
+    fun getJokeCategories(): NetworkResponse<List<String>>
 }

domain/src/main/java/com/devx/domain/useCase/GetJokeCategoriesUseCase.kt

@@ -1,10 +1,11 @@
 package com.devx.domain.useCase
 
 import com.devx.domain.repository.JokeRepository
+import com.devx.domain.util.NetworkResponse
 import javax.inject.Inject
 
 class GetJokeCategoriesUseCase @Inject constructor(private val jokeRepository: JokeRepository) {
-    operator fun invoke(): ArrayList<String> {
+    operator fun invoke(): NetworkResponse<List<String>> {
         return jokeRepository.getJokeCategories()
     }
 }

domain/src/main/java/com/devx/domain/useCase/GetJokeUseCase.kt

@@ -2,10 +2,11 @@ package com.devx.domain.useCase
 
 import com.devx.domain.model.JokeResponse
 import com.devx.domain.repository.JokeRepository
+import com.devx.domain.util.NetworkResponse
 import javax.inject.Inject
 
 class GetJokeUseCase @Inject constructor(private val jokeRepository: JokeRepository) {
-    suspend operator fun invoke(): JokeResponse {
+    suspend operator fun invoke(): NetworkResponse<JokeResponse> {
         return jokeRepository.getJoke()
     }
 }

domain/src/main/java/com/devx/domain/util/Mapper.kt

@@ -0,0 +1,5 @@
+package com.devx.domain.util
+
+interface Mapper<T> {
+    fun mapToDomain(): T
+}

domain/src/main/java/com/devx/domain/util/NetworkResponse.kt

@@ -0,0 +1,11 @@
+package com.devx.domain.util
+
+sealed class NetworkResponse<T>(
+    val data: T? = null,
+    val errorMessage: String? = null,
+    val exception: Throwable? = null,
+) {
+    class Success<T>(data: T) : NetworkResponse<T>(data = data)
+    class Error<T>(errorMessage: String?) : NetworkResponse<T>(errorMessage = errorMessage)
+    class Exception<T>(throwable: Throwable) : NetworkResponse<T>(exception = throwable)
+}