Authentication aufräumen, 3. Schritt Error Handling f. auth + HttpClient

shared/src/commonMain/kotlin/net/keinekekse/app/service/HttpClient.kt

@@ -2,12 +2,17 @@ package net.keinekekse.app.service
 
 import io.github.oshai.kotlinlogging.KotlinLogging
 import io.ktor.client.*
+import io.ktor.client.call.*
 import io.ktor.client.plugins.*
 import io.ktor.client.plugins.auth.*
 import io.ktor.client.plugins.auth.providers.*
 import io.ktor.client.plugins.contentnegotiation.*
+import io.ktor.client.request.*
 import io.ktor.serialization.kotlinx.json.*
+import io.ktor.util.network.*
+import kotlinx.io.IOException
 import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.SerializationException
 import kotlinx.serialization.json.Json
 import net.keinekekse.app.auth.Authenticator
 import org.koin.core.annotation.Single
@@ -18,6 +23,7 @@ private val logger = KotlinLogging.logger {}
 @Single
 fun createHttpClient(authenticator: Authenticator): HttpClient {
     val client = HttpClient {
+        expectSuccess = true
         install(Auth) {
             bearer {
                 loadTokens {
@@ -36,7 +42,6 @@ fun createHttpClient(authenticator: Authenticator): HttpClient {
                 }
             }
         }
-
         install(ContentNegotiation) {
             json(Json {
                 prettyPrint = true
@@ -50,6 +55,7 @@ fun createHttpClient(authenticator: Authenticator): HttpClient {
             requestTimeoutMillis = 10000
             connectTimeoutMillis = 5000
         }
+
     }
 
     client.plugin(HttpSend).intercept { request ->
@@ -67,3 +73,54 @@ fun createHttpClient(authenticator: Authenticator): HttpClient {
 
     return client
 }
+
+// HTTP-Error-Handling -> https://stackoverflow.com/questions/54679592/handling-exception-in-httpclient-ktor
+
+sealed class ApiResponse<out T, out E> {
+    /**
+     * Represents successful network responses (2xx).
+     */
+    data class Success<T>(val body: T) : ApiResponse<T, Nothing>()
+
+    sealed class ErrorResponse<E> : ApiResponse<Nothing, E>() {
+        /**
+         * Represents server (50x) and client (40x) errors.
+         */
+        data class HttpError<E>(val code: Int, val errorBody: E?) : ErrorResponse<E>()
+
+        /**
+         * Represent IOExceptions and connectivity issues.
+         */
+        data class NetworkError(val exception: String) : ErrorResponse<Nothing>()
+
+        /**
+         * Represent SerializationExceptions.
+         */
+        object SerializationError : ErrorResponse<Nothing>()
+    }
+}
+
+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.ErrorResponse.HttpError(e.response.status.value, e.errorBody())
+    } catch (e: ServerResponseException) {
+        ApiResponse.ErrorResponse.HttpError(e.response.status.value, e.errorBody())
+    } catch (e: IOException) {
+        ApiResponse.ErrorResponse.NetworkError(e.toString())
+    } catch (e: UnresolvedAddressException) { // no Network
+        ApiResponse.ErrorResponse.NetworkError(e.toString())
+    } catch (_: SerializationException) {
+        ApiResponse.ErrorResponse.SerializationError
+    }
+
+suspend inline fun <reified E> ResponseException.errorBody(): E? =
+    try {
+        response.body()
+    } catch (_: SerializationException) {
+        null
+    }