Refactor: Migrate network layer from Retrofit to Ktor

This commit migrates the network layer from Retrofit to Ktor.

Specific changes include:

-
 Replaced Retrofit with Ktor for network requests.
- Updated dependencies to include Ktor libraries.
- Refactored network service and data classes to use Ktor's API.
- Removed Retrofit-specific code and dependencies.
- Adjusted network module to provide Ktor client and services.
- Updated Pixabay
ImageRepository to use the new Ktor-based PixabayService.
- Introduced Result sealed class to handle network responses.
- Updated PhotoDetailViewModel to handle Result.Error state.

.idea/misc.xml

@@ -1,4 +1,3 @@
-<?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="ExternalStorageConfigurationManager" enabled="true" />
   <component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="jbr-17" project-jdk-type="JavaSDK">

app/src/main/java/dev/adriankuta/pixabay/PixabayNavGraph.kt

@@ -43,7 +43,6 @@ fun PixabayNavGraph(
         ) { entry ->
             PhotoDetailRoute(
                 photoId = entry.arguments?.getInt(PHOTO_ID_ARG)!!,
-                onBack = { navController.popBackStack() },
             )
         }
     }

core/ui/src/main/res/drawable/ic_comment.xml

@@ -3,7 +3,7 @@
     android:height="24dp"
     android:viewportWidth="960"
     android:viewportHeight="960">
-  <path
-      android:pathData="M280,560h400q17,0 28.5,-11.5T720,520q0,-17 -11.5,-28.5T680,480L280,480q-17,0 -28.5,11.5T240,520q0,17 11.5,28.5T280,560ZM280,440h400q17,0 28.5,-11.5T720,400q0,-17 -11.5,-28.5T680,360L280,360q-17,0 -28.5,11.5T240,400q0,17 11.5,28.5T280,440ZM280,320h400q17,0 28.5,-11.5T720,280q0,-17 -11.5,-28.5T680,240L280,240q-17,0 -28.5,11.5T240,280q0,17 11.5,28.5T280,320ZM160,720q-33,0 -56.5,-23.5T80,640v-480q0,-33 23.5,-56.5T160,80h640q33,0 56.5,23.5T880,160v623q0,27 -24.5,37.5T812,812l-92,-92L160,720ZM754,640 L800,685v-525L160,160v480h594ZM160,640v-480,480Z"
-      android:fillColor="#5f6368"/>
+    <path
+        android:fillColor="#5f6368"
+        android:pathData="M280,560h400q17,0 28.5,-11.5T720,520q0,-17 -11.5,-28.5T680,480L280,480q-17,0 -28.5,11.5T240,520q0,17 11.5,28.5T280,560ZM280,440h400q17,0 28.5,-11.5T720,400q0,-17 -11.5,-28.5T680,360L280,360q-17,0 -28.5,11.5T240,400q0,17 11.5,28.5T280,440ZM280,320h400q17,0 28.5,-11.5T720,280q0,-17 -11.5,-28.5T680,240L280,240q-17,0 -28.5,11.5T240,280q0,17 11.5,28.5T280,320ZM160,720q-33,0 -56.5,-23.5T80,640v-480q0,-33 23.5,-56.5T160,80h640q33,0 56.5,23.5T880,160v623q0,27 -24.5,37.5T812,812l-92,-92L160,720ZM754,640 L800,685v-525L160,160v480h594ZM160,640v-480,480Z" />
 </vector>

core/ui/src/main/res/drawable/ic_download.xml

@@ -3,7 +3,7 @@
     android:height="24dp"
     android:viewportWidth="960"
     android:viewportHeight="960">
-  <path
-      android:pathData="M480,623q-8,0 -15,-2.5t-13,-8.5L308,468q-12,-12 -11.5,-28t11.5,-28q12,-12 28.5,-12.5T365,411l75,75v-286q0,-17 11.5,-28.5T480,160q17,0 28.5,11.5T520,200v286l75,-75q12,-12 28.5,-11.5T652,412q11,12 11.5,28T652,468L508,612q-6,6 -13,8.5t-15,2.5ZM240,800q-33,0 -56.5,-23.5T160,720v-80q0,-17 11.5,-28.5T200,600q17,0 28.5,11.5T240,640v80h480v-80q0,-17 11.5,-28.5T760,600q17,0 28.5,11.5T800,640v80q0,33 -23.5,56.5T720,800L240,800Z"
-      android:fillColor="#5f6368"/>
+    <path
+        android:fillColor="#5f6368"
+        android:pathData="M480,623q-8,0 -15,-2.5t-13,-8.5L308,468q-12,-12 -11.5,-28t11.5,-28q12,-12 28.5,-12.5T365,411l75,75v-286q0,-17 11.5,-28.5T480,160q17,0 28.5,11.5T520,200v286l75,-75q12,-12 28.5,-11.5T652,412q11,12 11.5,28T652,468L508,612q-6,6 -13,8.5t-15,2.5ZM240,800q-33,0 -56.5,-23.5T160,720v-80q0,-17 11.5,-28.5T200,600q17,0 28.5,11.5T240,640v80h480v-80q0,-17 11.5,-28.5T760,600q17,0 28.5,11.5T800,640v80q0,33 -23.5,56.5T720,800L240,800Z" />
 </vector>

data/build.gradle.kts

@@ -23,16 +23,21 @@ android {
 }
 
 dependencies {
-    implementation(libs.retrofit)
-
-    implementation(platform(libs.okhttp.bom))
-    implementation(libs.okhttp)
-    implementation(libs.logging.interceptor)
-
     implementation(libs.androidx.paging.compose)
 
+
+    //Kotlin Serialization
     implementation(libs.kotlinx.serialization.json)
-    implementation(libs.retrofit2.kotlinx.serialization.converter)
+
+    //Ktor
+    implementation(libs.ktor.client.android)
+    implementation(libs.ktor.client.resources)
+    implementation(libs.ktor.client.content.negotiation)
+    implementation(libs.ktor.client.logging)
+    implementation(libs.ktor.serialization.kotlinx.json)
+
+    //Logging
+    implementation(libs.slf4j.android)
 
     implementation(libs.androidx.room.runtime)
     ksp(libs.androidx.room.compiler)

data/src/main/kotlin/dev/adriankuta/pixabay/data/Result.kt

@@ -0,0 +1,8 @@
+package dev.adriankuta.pixabay.data
+
+fun <T> Result<T>.isSuccess() = this is Result.Success<T>
+
+sealed interface Result<out T> {
+    data class Success<out T>(val data: T) : Result<T>
+    data class Error(val exception: Throwable) : Result<Nothing>
+}

data/src/main/kotlin/dev/adriankuta/pixabay/data/di/NetworkModule.kt

@@ -1,52 +1,58 @@
 package dev.adriankuta.pixabay.data.di
 
-import com.jakewharton.retrofit2.converter.kotlinx.serialization.asConverterFactory
+import dagger.Binds
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.InstallIn
 import dagger.hilt.components.SingletonComponent
 import dev.adriankuta.pixabay.data.BuildConfig
+import dev.adriankuta.pixabay.data.network.KtorPixabayService
 import dev.adriankuta.pixabay.data.network.PixabayService
+import io.ktor.client.HttpClient
+import io.ktor.client.engine.android.Android
+import io.ktor.client.plugins.contentnegotiation.ContentNegotiation
+import io.ktor.client.plugins.defaultRequest
+import io.ktor.client.plugins.logging.Logging
+import io.ktor.client.plugins.resources.Resources
+import io.ktor.http.URLProtocol
+import io.ktor.serialization.kotlinx.json.json
 import kotlinx.serialization.json.Json
-import okhttp3.MediaType.Companion.toMediaType
-import okhttp3.OkHttpClient
-import okhttp3.logging.HttpLoggingInterceptor
-import retrofit2.Retrofit
 import javax.inject.Singleton
 
 @InstallIn(SingletonComponent::class)
 @Module
-internal class NetworkModule {
-    @Singleton
-    @Provides
-    fun provideHttpLoggingInterceptor(): HttpLoggingInterceptor {
-        val logging = HttpLoggingInterceptor()
-        logging.level =
-            if (BuildConfig.DEBUG) HttpLoggingInterceptor.Level.BODY else HttpLoggingInterceptor.Level.NONE
-        return logging
-    }
+internal abstract class NetworkModule {
 
     @Singleton
-    @Provides
-    fun provideOkHttpClient(
-        httpLoggingInterceptor: HttpLoggingInterceptor
-    ): OkHttpClient {
-        return OkHttpClient.Builder()
-            .addInterceptor(httpLoggingInterceptor)
-            .build()
-    }
+    @Binds
+    abstract fun provideKtorApi(ktorPixabayService: KtorPixabayService): PixabayService
 
-    @Singleton
-    @Provides
-    fun providePixabayApi(
-        okHttpClient: OkHttpClient
-    ): PixabayService {
-        val networkJson = Json { ignoreUnknownKeys = true }
-        return Retrofit.Builder()
-            .client(okHttpClient)
-            .baseUrl("https://pixabay.com/")
-            .addConverterFactory(networkJson.asConverterFactory("application/json".toMediaType()))
-            .build()
-            .create(PixabayService::class.java)
+    companion object {
+        @Singleton
+        @Provides
+        fun provideKtorClient(): HttpClient {
+            return HttpClient(Android) {
+                install(ContentNegotiation) {
+                    json(
+                        Json {
+                            ignoreUnknownKeys = true
+                        }
+                    )
+                }
+                install(Resources)
+                install(Logging)
+                defaultRequest {
+                    url {
+                        protocol = URLProtocol.HTTP
+                        host = "pixabay.com"
+                        parameters.append("key", BuildConfig.PIXABAY_API_KEY)
+                    }
+                }
+                engine {
+                    connectTimeout = 100_000
+                    socketTimeout = 100_000
+                }
+            }
+        }
     }
 }

data/src/main/kotlin/dev/adriankuta/pixabay/data/di/PersistanceModule.kt

@@ -8,7 +8,6 @@ import dagger.hilt.InstallIn
 import dagger.hilt.android.qualifiers.ApplicationContext
 import dagger.hilt.components.SingletonComponent
 import dev.adriankuta.pixabay.data.room.AppDatabase
-import dev.adriankuta.pixabay.data.room.dao.PixabayImagesDao
 import javax.inject.Singleton
 
 @InstallIn(SingletonComponent::class)

data/src/main/kotlin/dev/adriankuta/pixabay/data/dto/request/PixabayImages.kt

@@ -0,0 +1,12 @@
+package dev.adriankuta.pixabay.data.dto.request
+
+import io.ktor.resources.Resource
+import kotlinx.serialization.SerialName
+
+@Resource("/api")
+internal class PixabayImages(
+    @SerialName("q")
+    val query: String,
+    val page: Int,
+    val pageSize: Int
+)

data/src/main/kotlin/dev/adriankuta/pixabay/data/dto/request/PixabayImagesById.kt

@@ -0,0 +1,8 @@
+package dev.adriankuta.pixabay.data.dto.request
+
+import io.ktor.resources.Resource
+
+@Resource("/api")
+internal class PixabayImagesById(
+    val id: String,
+)

data/src/main/kotlin/dev/adriankuta/pixabay/data/network/KtorPixabayService.kt

@@ -0,0 +1,26 @@
+package dev.adriankuta.pixabay.data.network
+
+import dev.adriankuta.pixabay.data.dto.request.PixabayImages
+import dev.adriankuta.pixabay.data.dto.request.PixabayImagesById
+import dev.adriankuta.pixabay.data.dto.response.SearchPixabayImagesResponse
+import io.ktor.client.HttpClient
+import io.ktor.client.call.body
+import io.ktor.client.plugins.resources.get
+import javax.inject.Inject
+
+internal class KtorPixabayService @Inject constructor(
+    private val client: HttpClient,
+) : PixabayService {
+
+    override suspend fun searchImages(
+        query: String,
+        page: Int,
+        pageSize: Int
+    ): SearchPixabayImagesResponse {
+        return client.get(PixabayImages(query, page, pageSize)).body()
+    }
+
+    override suspend fun searchImageById(id: String): SearchPixabayImagesResponse {
+        return client.get(PixabayImagesById(id)).body()
+    }
+}

data/src/main/kotlin/dev/adriankuta/pixabay/data/network/PixabayService.kt

@@ -1,23 +1,16 @@
 package dev.adriankuta.pixabay.data.network
 
-import dev.adriankuta.pixabay.data.BuildConfig
 import dev.adriankuta.pixabay.data.dto.response.SearchPixabayImagesResponse
-import retrofit2.http.GET
-import retrofit2.http.Query
 
 internal interface PixabayService {
 
-    @GET("api")
     suspend fun searchImages(
-        @Query("q") query: String,
-        @Query("page") page: Int,
-        @Query("per_page") pageSize: Int,
-        @Query("key") key: String = BuildConfig.PIXABAY_API_KEY
+        query: String,
+        page: Int,
+        pageSize: Int
     ): SearchPixabayImagesResponse
 
-    @GET("api")
     suspend fun searchImageById(
-        @Query("id") query: String,
-        @Query("key") key: String = BuildConfig.PIXABAY_API_KEY
+        id: String,
     ): SearchPixabayImagesResponse
 }

data/src/main/kotlin/dev/adriankuta/pixabay/data/paging/PixabayPagingSource.kt

@@ -5,7 +5,6 @@ import androidx.paging.PagingState
 import dev.adriankuta.pixabay.data.model.PixabayImage
 import dev.adriankuta.pixabay.data.network.PixabayService
 import dev.adriankuta.pixabay.data.repository.PixabayImageRepository.Companion.NETWORK_PAGE_SIZE
-import retrofit2.HttpException
 import java.io.IOException
 
 private const val STARTING_PAGE_INDEX = 1
@@ -34,8 +33,6 @@ internal class PixabayPagingSource(
             )
         } catch (exception: IOException) {
             return LoadResult.Error(exception)
-        } catch (exception: HttpException) {
-            return LoadResult.Error(exception)
         }
     }
 

data/src/main/kotlin/dev/adriankuta/pixabay/data/paging/PixabayRemoteMediator.kt

@@ -7,12 +7,10 @@ import androidx.paging.LoadType
 import androidx.paging.PagingState
 import androidx.paging.RemoteMediator
 import androidx.room.withTransaction
-import dev.adriankuta.pixabay.data.model.PixabayImage
 import dev.adriankuta.pixabay.data.network.PixabayService
 import dev.adriankuta.pixabay.data.room.AppDatabase
 import dev.adriankuta.pixabay.data.room.entity.PixabayImageEntity
 import dev.adriankuta.pixabay.data.room.entity.RemoteKeys
-import retrofit2.HttpException
 import java.io.IOException
 
 private const val STARTING_PAGE_INDEX = 1
@@ -78,8 +76,6 @@ internal class PixabayRemoteMediator(
             return MediatorResult.Success(endOfPaginationReached = endOfPaginationReached)
         } catch (exception: IOException) {
             return MediatorResult.Error(exception)
-        } catch (exception: HttpException) {
-            return MediatorResult.Error(exception)
         }
     }
 

data/src/main/kotlin/dev/adriankuta/pixabay/data/repository/ImageRepository.kt

@@ -1,14 +1,15 @@
 package dev.adriankuta.pixabay.data.repository
 
 import androidx.paging.PagingData
+import dev.adriankuta.pixabay.data.Result
 import dev.adriankuta.pixabay.data.model.PixabayImage
 import kotlinx.coroutines.flow.Flow
 
 interface ImageRepository {
 
-    suspend fun searchImageById(id: Int): PixabayImage
+    suspend fun searchImageById(id: Int): Result<PixabayImage>
 
-    suspend fun searchImages(query: String, page: Int, pageSize: Int): List<PixabayImage>
+    suspend fun searchImages(query: String, page: Int, pageSize: Int): Result<List<PixabayImage>>
 
     fun getSearchResultStream(query: String): Flow<PagingData<PixabayImage>>
 }

data/src/main/kotlin/dev/adriankuta/pixabay/data/repository/PixabayImageRepository.kt

@@ -7,6 +7,7 @@ import androidx.paging.Pager
 import androidx.paging.PagingConfig
 import androidx.paging.PagingData
 import androidx.paging.map
+import dev.adriankuta.pixabay.data.Result
 import dev.adriankuta.pixabay.data.model.PixabayImage
 import dev.adriankuta.pixabay.data.network.PixabayService
 import dev.adriankuta.pixabay.data.paging.PixabayPagingSource
@@ -22,24 +23,32 @@ internal class PixabayImageRepository @Inject constructor(
     private val pixabayService: PixabayService
 ) : ImageRepository {
 
-    override suspend fun searchImageById(id: Int): PixabayImage {
+    override suspend fun searchImageById(id: Int): Result<PixabayImage> {
         return runCatching {
             pixabayService.searchImageById(id.toString())
         }.mapCatching { response ->
-            PixabayImage(response.hits.first())
+            Result.Success(PixabayImage(response.hits.first()))
         }.onFailure { e ->
             Timber.e(e)
-        }.getOrThrow()
+        }.getOrElse {
+            Result.Error(it)
+        }
     }
 
-    override suspend fun searchImages(query: String, page: Int, pageSize: Int): List<PixabayImage> {
+    override suspend fun searchImages(
+        query: String,
+        page: Int,
+        pageSize: Int
+    ): Result<List<PixabayImage>> {
         return runCatching {
             pixabayService.searchImages(query, page, pageSize)
         }.mapCatching { response ->
-            response.hits.map { PixabayImage(it) }
+            Result.Success(response.hits.map { PixabayImage(it) })
         }.onFailure { e ->
             Timber.e(e)
-        }.getOrThrow()
+        }.getOrElse {
+            Result.Error(it)
+        }
     }
 
     override fun getSearchResultStream(query: String): Flow<PagingData<PixabayImage>> {
@@ -75,6 +84,6 @@ internal class PixabayImageRepository @Inject constructor(
 
     companion object {
         const val NETWORK_PAGE_SIZE = 30
-        const val USE_CACHE_PAGER = true
+        const val USE_CACHE_PAGER = false
     }
 }

data/src/main/kotlin/dev/adriankuta/pixabay/data/room/entity/PixabayImageEntity.kt

@@ -33,7 +33,7 @@ internal data class PixabayImageEntity(
     @ColumnInfo(COLUMN_USER) val user: String,
     @ColumnInfo(COLUMN_USER_IMAGE_URL) val userImageURL: String,
 
-) {
+    ) {
     constructor(pixabayImageResponse: PixabayImageResponse, queryUsed: String) :
             this(
                 id = pixabayImageResponse.id,

feature/details/src/main/kotlin/dev/adriankuta/pixabay/feature/details/PhotoDetailRoute.kt

@@ -39,7 +39,6 @@ import dev.adriankuta.pixabay.feature.details.di.PhotoDetailsViewModelFactory
 @Composable
 fun PhotoDetailRoute(
     photoId: Int,
-    onBack: () -> Unit,
     modifier: Modifier = Modifier,
     viewModel: PhotoDetailViewModel = hiltViewModel(
         creationCallback = { factory: PhotoDetailsViewModelFactory ->

feature/details/src/main/kotlin/dev/adriankuta/pixabay/feature/details/PhotoDetailViewModel.kt

@@ -5,6 +5,7 @@ import androidx.lifecycle.viewModelScope
 import dagger.assisted.Assisted
 import dagger.assisted.AssistedInject
 import dagger.hilt.android.lifecycle.HiltViewModel
+import dev.adriankuta.pixabay.data.Result
 import dev.adriankuta.pixabay.data.repository.ImageRepository
 import dev.adriankuta.pixabay.feature.details.di.PhotoDetailsViewModelFactory
 import kotlinx.coroutines.flow.SharingStarted
@@ -23,7 +24,12 @@ class PhotoDetailViewModel @AssistedInject constructor(
     }
 
     val uiState = loadedData
-        .map { PhotoDetailUiState.Success(it) }
+        .map {
+            when (it) {
+                is Result.Success -> PhotoDetailUiState.Success(it.data)
+                is Result.Error -> PhotoDetailUiState.Error
+            }
+        }
         .stateIn(
             scope = viewModelScope,
             started = SharingStarted.WhileSubscribed(stopTimeoutMillis = 5000),

feature/search/src/main/kotlin/dev/adriankuta/pixabay/feature/search/SearchRoute.kt

@@ -17,7 +17,6 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.stringResource
-import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.paging.LoadState

feature/search/src/main/kotlin/dev/adriankuta/pixabay/feature/search/SearchUiState.kt

@@ -1,7 +1,5 @@
 package dev.adriankuta.pixabay.feature.search
 
-import dev.adriankuta.pixabay.data.model.PixabayImage
-
 
 data class SearchUiState(
     val query: String = ""

gradle/libs.versions.toml

@@ -1,7 +1,7 @@
 [versions]
 androidxNavigation = "2.7.7"
 androidGradlePlugin = "8.1.4"
-agp = "8.6.0-beta02"
+agp = "8.6.0-rc01"
 coilCompose = "2.6.0"
 composeCompiler = "1.5.14"
 kotlin = "1.9.24"
@@ -15,13 +15,13 @@ androidxLifecycle = "2.8.3"
 activityCompose = "1.9.0"
 composeBom = "2024.06.00"
 kotlinxSerializationJson = "1.6.0"
+ktor = "2.3.12"
 okhttpBom = "4.12.0"
 pagingCompose = "3.3.0"
-retrofit2KotlinxSerializationConverter = "1.0.0"
 room = "2.6.1"
+slf4jAndroid = "1.7.36"
 timber = "5.0.1"
 hilt = "2.51.1"
-retrofit = "2.11.0"
 ksp = "1.9.24-1.0.20"
 
 [libraries]
@@ -52,14 +52,18 @@ androidx-ui-test-manifest = { group = "androidx.compose.ui", name = "ui-test-man
 androidx-ui-test-junit4 = { group = "androidx.compose.ui", name = "ui-test-junit4" }
 androidx-material3 = { group = "androidx.compose.material3", name = "material3" }
 kotlinx-serialization-json = { module = "org.jetbrains.kotlinx:kotlinx-serialization-json", version.ref = "kotlinxSerializationJson" }
+ktor-client-android = { group = "io.ktor", name = "ktor-client-android", version.ref = "ktor" }
+ktor-client-resources = { group = "io.ktor", name = "ktor-client-resources", version.ref = "ktor" }
+ktor-client-content-negotiation = { group = "io.ktor", name = "ktor-client-content-negotiation", version.ref = "ktor" }
+ktor-client-logging = { group = "io.ktor", name = "ktor-client-logging", version.ref = "ktor" }
+ktor-serialization-kotlinx-json = { group = "io.ktor", name = "ktor-serialization-kotlinx-json", version.ref = "ktor" }
 logging-interceptor = { module = "com.squareup.okhttp3:logging-interceptor" }
 okhttp = { module = "com.squareup.okhttp3:okhttp" }
 okhttp-bom = { module = "com.squareup.okhttp3:okhttp-bom", version.ref = "okhttpBom" }
-retrofit2-kotlinx-serialization-converter = { module = "com.jakewharton.retrofit:retrofit2-kotlinx-serialization-converter", version.ref = "retrofit2KotlinxSerializationConverter" }
+slf4j-android = { module = "org.slf4j:slf4j-android", version.ref = "slf4jAndroid" }
 timber = { module = "com.jakewharton.timber:timber", version.ref = "timber" }
 hilt-android = { group = "com.google.dagger", name = "hilt-android", version.ref = "hilt" }
 hilt-compiler = { group = "com.google.dagger", name = "hilt-compiler", version.ref = "hilt" }
-retrofit = { group = "com.squareup.retrofit2", name = "retrofit", version.ref = "retrofit" }
 
 [plugins]
 android-application = { id = "com.android.application", version.ref = "agp" }