Use ktor and kotlinX serialization

Author: rahulsainani

app/build.gradle.kts

@@ -22,6 +22,7 @@ plugins {
     alias(libs.plugins.kotlin.compose.compiler)
     alias(libs.plugins.kotlin.ksp)
     alias(libs.plugins.kotlin.parcelize)
+    alias(libs.plugins.kotlin.serialization)
 }
 
 val appConfig = AppConfig()
@@ -99,7 +100,6 @@ dependencies {
     implementation(libs.ktor.client.content.negotiation)
     implementation(libs.kotlinx.serialization.json)
     implementation(libs.ktor.serialization.kotlinx.json)
-    implementation(libs.converter.gson)
 
     // Compose
     // @see: https://developer.android.google.cn/develop/ui/compose/setup?hl=en#kotlin_1
@@ -130,6 +130,7 @@ dependencies {
     testImplementation(libs.junit)
     testImplementation(libs.mockk)
     testImplementation(libs.robolectric)
+    testImplementation(libs.ktor.client.mock)
 
     // UI tests dependencies
     androidTestImplementation(composeBom)

app/src/main/kotlin/com/fernandocejas/sample/AllFeatures.kt

@@ -0,0 +1,15 @@
+package com.fernandocejas.sample
+
+import com.fernandocejas.sample.core.navigation.navigationFeature
+import com.fernandocejas.sample.core.network.networkFeature
+import com.fernandocejas.sample.features.auth.authFeature
+import com.fernandocejas.sample.features.login.loginFeature
+import com.fernandocejas.sample.features.movies.di.moviesFeature
+
+fun allFeatures() = listOf(
+    networkFeature(),
+    authFeature(),
+    loginFeature(),
+    moviesFeature(),
+    navigationFeature(),
+)

app/src/main/kotlin/com/fernandocejas/sample/AndroidApplication.kt

@@ -16,8 +16,6 @@
 package com.fernandocejas.sample
 
 import android.app.Application
-import com.fernandocejas.sample.core.allFeatures
-import com.fernandocejas.sample.core.di.coreModule
 import org.koin.android.ext.koin.androidContext
 import org.koin.android.ext.koin.androidLogger
 import org.koin.core.context.GlobalContext.startKoin

app/src/main/kotlin/com/fernandocejas/sample/core/di/CoreModule.kt

@@ -1,9 +1,5 @@
-package com.fernandocejas.sample.core
+package com.fernandocejas.sample.core.di
 
-import com.fernandocejas.sample.core.di.coreModule
-import com.fernandocejas.sample.features.auth.authFeature
-import com.fernandocejas.sample.features.login.loginFeature
-import com.fernandocejas.sample.features.movies.moviesFeature
 import org.koin.core.module.Module
 
 /**
@@ -45,15 +41,3 @@ interface Feature {
      */
     // fun databaseTables(): List<Table> = emptyList()
 }
-
-private fun coreFeature() = object : Feature {
-    override fun name() = "core"
-    override fun diModule() = coreModule
-}
-
-fun allFeatures() = listOf(
-    coreFeature(),
-    authFeature(),
-    loginFeature(),
-    moviesFeature(),
-)

app/src/main/kotlin/com/fernandocejas/sample/core/Core.kt renamed to app/src/main/kotlin/com/fernandocejas/sample/core/di/Feature.kt

@@ -21,10 +21,14 @@ import android.content.Intent
 import android.net.Uri
 import android.view.View
 import androidx.fragment.app.FragmentActivity
+import com.fernandocejas.sample.core.di.Feature
 import com.fernandocejas.sample.core.extension.emptyString
 import com.fernandocejas.sample.features.auth.credentials.Authenticator
 import com.fernandocejas.sample.features.movies.ui.MovieView
 import com.fernandocejas.sample.features.movies.ui.MoviesActivity
+import org.koin.core.module.Module
+import org.koin.core.module.dsl.singleOf
+import org.koin.dsl.module
 
 
 class Navigator(private val authenticator: Authenticator) {
@@ -83,4 +87,10 @@ class Navigator(private val authenticator: Authenticator) {
     class Extras(val transitionSharedElement: View)
 }
 
-
+// temporary solution to compile till Navigator is deleted
+fun navigationFeature() = object : Feature {
+    override fun name() = "navigation"
+    override fun diModule() = module  {
+        singleOf(::Navigator)
+    }
+}

app/src/main/kotlin/com/fernandocejas/sample/core/navigation/Navigator.kt

@@ -0,0 +1,56 @@
+package com.fernandocejas.sample.core.network
+
+import com.fernandocejas.sample.core.functional.Either
+import com.fernandocejas.sample.core.functional.toLeft
+import com.fernandocejas.sample.core.functional.toRight
+
+sealed class ApiResponse<out T, out E> {
+    /**
+     * Represents successful network responses (2xx).
+     */
+    data class Success<T>(val body: T) : ApiResponse<T, Nothing>()
+
+    sealed class Error<E> : ApiResponse<Nothing, E>() {
+        /**
+         * Represents server (50x) and client (40x) errors.
+         */
+        data class HttpError<E>(val code: Int, val errorBody: E?) : Error<E>()
+
+        /**
+         * Represent IOExceptions and connectivity issues.
+         */
+        data object NetworkError : Error<Nothing>()
+
+        /**
+         * Represent SerializationExceptions.
+         */
+        data object SerializationError : Error<Nothing>()
+    }
+}
+
+// Side Effect helpers
+inline fun <T, E> ApiResponse<T, E>.onSuccess(block: (T) -> Unit): ApiResponse<T, E> {
+    if (this is ApiResponse.Success) {
+        block(body)
+    }
+    return this
+}
+
+fun <T, E> ApiResponse<T, E>.toEither(): Either<E?, T> {
+    return when (this) {
+        is ApiResponse.Success -> body.toRight()
+        is ApiResponse.Error.HttpError -> errorBody.toLeft()
+        is ApiResponse.Error.NetworkError -> null.toLeft()
+        is ApiResponse.Error.SerializationError -> null.toLeft()
+    }
+}
+
+fun <T, E, F, D> ApiResponse<T, E>.toEither(
+    successTransform: (T) -> D,
+    errorTransform: (ApiResponse.Error<E>) -> F,
+): Either<F, D> {
+    return when (this) {
+        is ApiResponse.Success -> successTransform(body).toRight()
+        is ApiResponse.Error -> errorTransform(this).toLeft()
+    }
+}

app/src/main/kotlin/com/fernandocejas/sample/core/network/ApiResponse.kt

@@ -0,0 +1,34 @@
+package com.fernandocejas.sample.core.network
+
+import io.ktor.client.HttpClient
+import io.ktor.client.call.body
+import io.ktor.client.plugins.ClientRequestException
+import io.ktor.client.plugins.ResponseException
+import io.ktor.client.plugins.ServerResponseException
+import io.ktor.client.request.HttpRequestBuilder
+import io.ktor.client.request.request
+import io.ktor.serialization.JsonConvertException
+import kotlinx.io.IOException
+
+suspend inline fun <reified T, reified E> HttpClient.safeRequest(
+    block: HttpRequestBuilder.() -> Unit,
+): ApiResponse<T, E> =
+    try {
+        val response = request { block() }
+        ApiResponse.Success(response.body())
+    } catch (e: ClientRequestException) {
+        ApiResponse.Error.HttpError(e.response.status.value, e.errorBody())
+    } catch (e: ServerResponseException) {
+        ApiResponse.Error.HttpError(e.response.status.value, e.errorBody())
+    } catch (e: IOException) {
+        ApiResponse.Error.NetworkError
+    } catch (e: JsonConvertException) {
+        ApiResponse.Error.SerializationError
+    }
+
+suspend inline fun <reified E> ResponseException.errorBody(): E? =
+    try {
+        response.body()
+    } catch (e: JsonConvertException) {
+        null
+    }

app/src/main/kotlin/com/fernandocejas/sample/core/network/HttpClientX.kt

@@ -17,8 +17,11 @@ package com.fernandocejas.sample.core.network
 
 import android.content.Context
 import android.net.NetworkCapabilities
-import android.os.Build
 import com.fernandocejas.sample.core.extension.connectivityManager
+import com.fernandocejas.sample.core.failure.Failure
+import com.fernandocejas.sample.core.functional.Either
+import com.fernandocejas.sample.core.functional.toLeft
+import com.fernandocejas.sample.core.functional.toRight
 
 /**
  * Injectable class which returns information about the network connection state.
@@ -37,4 +40,11 @@ class NetworkHandler(private val context: Context) {
             else -> false
         }
     }
+
+    inline fun <T> whenAvailable(
+        whenAvailable: () -> T,
+    ): Either<Failure, T> = when (isNetworkAvailable()) {
+        true -> whenAvailable().toRight()
+        false -> Failure.NetworkConnection.toLeft()
+    }
 }

app/src/main/kotlin/com/fernandocejas/sample/core/network/NetworkHandler.kt

@@ -0,0 +1,54 @@
+package com.fernandocejas.sample.core.network
+
+import co.touchlab.kermit.Logger
+import com.fernandocejas.sample.core.di.Feature
+import io.ktor.client.HttpClient
+import io.ktor.client.engine.okhttp.OkHttp
+import io.ktor.client.plugins.HttpTimeout
+import io.ktor.client.plugins.cache.HttpCache
+import io.ktor.client.plugins.contentnegotiation.ContentNegotiation
+import io.ktor.client.plugins.logging.LogLevel
+import io.ktor.client.plugins.logging.Logging
+import io.ktor.http.ContentType
+import io.ktor.serialization.kotlinx.json.json
+import kotlinx.serialization.json.Json
+import org.koin.core.module.dsl.singleOf
+import org.koin.dsl.module
+import io.ktor.client.plugins.logging.Logger as KtorLogger
+
+fun networkFeature() = object : Feature {
+    override fun name() = "network"
+    override fun diModule() = networkModule
+}
+
+private val networkModule = module {
+    singleOf(::NetworkHandler)
+    single { json }
+    single { client }
+}
+
+private val json = Json {
+    ignoreUnknownKeys = true
+    explicitNulls = false
+}
+
+private val client = HttpClient(OkHttp) {
+    engine {
+        config {
+            followRedirects(true)
+        }
+    }
+    install(HttpCache)
+    install(HttpTimeout)
+    install(ContentNegotiation) {
+        json(json, ContentType.Text.Plain)
+    }
+    install(Logging) {
+        logger = object : KtorLogger {
+            override fun log(message: String) {
+                Logger.withTag("HTTP").d { "\uD83C\uDF10 $message" }
+            }
+        }
+        level = LogLevel.HEADERS
+    }
+}