add simple converters to translate error response to an Either return type of retrofit service methods

app/build.gradle.kts

@@ -12,7 +12,7 @@ android {
 
     defaultConfig {
         applicationId = "com.iqball.app"
-        minSdk = 21
+        minSdk = 28
         targetSdk = 34
         versionCode = 1
         versionName = "1.0"

app/src/main/java/com/iqball/app/MainActivity.kt

@@ -9,6 +9,8 @@ import androidx.compose.material3.Surface
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
 import com.google.gson.Gson
+import com.google.gson.GsonBuilder
+import com.iqball.app.api.EitherBodyConverter
 import com.iqball.app.api.EitherCallAdapterFactory
 import com.iqball.app.api.service.IQBallService
 import com.iqball.app.page.RegisterPage
@@ -28,18 +30,10 @@ class MainActivity : ComponentActivity() {
         val gson = Gson()
 
         val retrofit = Retrofit.Builder()
+            .addConverterFactory(EitherBodyConverter.create())
             .addConverterFactory(GsonConverterFactory.create(gson))
             .addCallAdapterFactory(EitherCallAdapterFactory.create(gson))
-            .addConverterFactory(object : Converter.Factory() {
-                override fun responseBodyConverter(
-                    type: Type,
-                    annotations: Array<out Annotation>,
-                    retrofit: Retrofit
-                ): Converter<ResponseBody, *>? {
-                    return super.responseBodyConverter(type, annotations, retrofit)
-                }
-            })
-            .baseUrl("http://grospc:5254")
+            .baseUrl("https://iqball.maxou.dev/api/dotnet-master/")
             .client(
                 OkHttpClient.Builder()
                     .addInterceptor { it.proceed(it.request()) }

app/src/main/java/com/iqball/app/api/EitherBodyConverter.kt

@@ -0,0 +1,37 @@
+package com.iqball.app.api
+
+import arrow.core.Either
+import okhttp3.ResponseBody
+import retrofit2.Call
+import retrofit2.Converter
+import retrofit2.Retrofit
+import java.lang.reflect.ParameterizedType
+import java.lang.reflect.Type
+
+class EitherBodyConverter : Converter.Factory() {
+    override fun responseBodyConverter(
+        type: Type,
+        annotations: Array<out Annotation>,
+        retrofit: Retrofit
+    ): Converter<ResponseBody, *>? {
+
+        if (type !is ParameterizedType) {
+            return null
+        }
+        if (type.rawType != Call::class.java) {
+            return null
+        }
+        val eitherType = type.actualTypeArguments.first()
+        if (eitherType !is ParameterizedType || eitherType.rawType != Either::class.java) {
+            return null
+        }
+
+        val eitherRightType = eitherType.actualTypeArguments[1]
+        return retrofit.nextResponseBodyConverter<Any>(this, eitherRightType, annotations)
+    }
+
+    companion object {
+        fun create() = EitherBodyConverter()
+    }
+
+}

app/src/main/java/com/iqball/app/api/EitherCallAdapterFactory.kt

@@ -1,5 +1,8 @@
 package com.iqball.app.api
 
+import android.os.Build
+import androidx.annotation.RequiresApi
+import arrow.core.Either
 import com.google.gson.Gson
 import com.skydoves.retrofit.adapters.arrow.EitherCallAdapterFactory
 import retrofit2.Call
@@ -13,13 +16,21 @@ class EitherCallAdapterFactory(private val gson: Gson) : CallAdapter.Factory() {
         returnType: Type,
         annotations: Array<out Annotation>,
         retrofit: Retrofit
-    ): CallAdapter<*, *> {
+    ): CallAdapter<*, *>? {
+        if (returnType !is ParameterizedType) {
+            return null
+        }
+        if (returnType.rawType != Call::class.java) {
+            return null
+        }
+        val eitherType = returnType.actualTypeArguments.first()
+        if (eitherType !is ParameterizedType || eitherType.rawType != Either::class.java) {
+            return null
+        }
         return object : CallAdapter<Any, Any> {
             override fun responseType(): Type = returnType
 
             override fun adapt(call: Call<Any>): EitherCall<Any, Any> {
-                val callType = returnType as ParameterizedType
-                val eitherType = callType.actualTypeArguments.first() as ParameterizedType
                 return EitherCall(gson, eitherType, call)
             }
         }

app/src/main/java/com/iqball/app/api/service/AuthService.kt

@@ -3,26 +3,26 @@ package com.iqball.app.api.service
 import arrow.core.Either
 import kotlinx.datetime.LocalDateTime
 import kotlinx.serialization.Serializable
-import retrofit2.Call
-import retrofit2.HttpException
 import retrofit2.http.Body
+import retrofit2.http.GET
+import retrofit2.http.Header
 import retrofit2.http.POST
 
 interface AuthService {
 
     @Serializable
-    data class AuthResponse(val token: String, val expirationDate: LocalDateTime)
+    data class AuthResponse(val token: String, val expirationDate: String)
 
     @Serializable
     data class RegisterRequest(val username: String, val email: String, val password: String)
 
-    @POST("/auth/register")
+    @POST("auth/register")
     suspend fun register(@Body req: RegisterRequest): APIResult<AuthResponse>
 
     data class LoginRequest(val email: String, val password: String)
 
-    @POST("/auth/token")
-    suspend fun login(@Body req: LoginRequest): Call<AuthResponse>
+    @POST("auth/token")
+    suspend fun login(@Body req: LoginRequest): APIResult<AuthResponse>
 
 
 }

app/src/main/java/com/iqball/app/api/service/IQBallService.kt

@@ -6,4 +6,4 @@ import retrofit2.Call
 typealias ErrorResponseResult = Map<String, Array<String>>
 typealias APIResult<R> = Either<ErrorResponseResult, R>
 
-interface IQBallService : AuthService
+interface IQBallService : AuthService, UserService

app/src/main/java/com/iqball/app/api/service/UserService.kt

@@ -0,0 +1,11 @@
+package com.iqball.app.api.service
+
+import retrofit2.http.GET
+import retrofit2.http.Header
+
+interface UserService {
+    data class UserDataResponse(val teams: List<Any>, val tactics: List<Any>)
+
+    @GET("user-data")
+    suspend fun getUserData(@Header("Authorization") auth: String): APIResult<UserDataResponse>
+}

app/src/main/java/com/iqball/app/page/RegisterPage.kt

@@ -8,8 +8,11 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import arrow.core.Either
+import com.iqball.app.api.service.AuthService
 import com.iqball.app.api.service.AuthService.RegisterRequest
 import com.iqball.app.api.service.IQBallService
+import com.iqball.app.session.Authentication
+import com.iqball.app.session.MutableSession
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.delay
@@ -22,26 +25,30 @@ fun RegisterPage(service: IQBallService) {
 
     var text by remember { mutableStateOf("No message !") }
 
-
     runBlocking {
-        val result = service.register(RegisterRequest("abcdefg", "a@m.com", "123456"))
+        val result = service.login(AuthService.LoginRequest("maxime@mail.com", "123456"))
 
         when (result) {
-            is Either.Left -> println("Error : " + result.value)
-            is Either.Right -> println("Success : " + result.value)
+            is Either.Left -> {
+                println("Error : " + result.value)
+                text = result.toString()
+            }
+            is Either.Right -> {
+                val token = result.value.token
+                val userDataResponse = service.getUserData(token)
+
+                when (userDataResponse) {
+                    is Either.Left -> println("Error User Data : " + userDataResponse.value)
+                    is Either.Right -> println("Success User Data : " + userDataResponse.value)
+                }
+
+                text = userDataResponse.toString()
+            }
         }
 
         println(result)
-        text = result.toString()
         Log.i("%", result.toString())
     }
 
     Text(text = text)
 }
-
-suspend fun updateTextIn5Sec(setText: (String) -> Unit) = coroutineScope {
-    launch(Dispatchers.IO) {
-        delay(5000)
-        setText("test")
-    }
-}

app/src/main/java/com/iqball/app/session/Authentication.kt

@@ -0,0 +1,5 @@
+package com.iqball.app.session
+
+import kotlinx.datetime.LocalDateTime
+
+data class Authentication(val token: String, val expirationDate: LocalDateTime)

app/src/main/java/com/iqball/app/session/MutableSession.kt

@@ -0,0 +1,5 @@
+package com.iqball.app.session
+
+interface MutableSession : Session {
+    override var auth: Authentication
+}

app/src/main/java/com/iqball/app/session/Session.kt

@@ -0,0 +1,5 @@
+package com.iqball.app.session
+
+interface Session {
+    val auth: Authentication
+}