feat: Add ability to parse status code and headers to NetworkResponse.UnknownError

Author: haroldadmin

src/main/kotlin/com/haroldadmin/cnradapter/NetworkResponse.kt

@@ -32,5 +32,9 @@ sealed class NetworkResponse<out T : Any, out U : Any> {
      *
      * An example of such an error is JSON parsing exception thrown by a serialization library.
      */
-    data class UnknownError(val error: Throwable) : NetworkResponse<Nothing, Nothing>()
+    data class UnknownError(
+        val error: Throwable,
+        val code: Int? = null,
+        val headers: Headers? = null,
+    ) : NetworkResponse<Nothing, Nothing>()
 }

src/main/kotlin/com/haroldadmin/cnradapter/ResponseHandler.kt

@@ -10,52 +10,56 @@ import java.lang.reflect.Type
  */
 internal object ResponseHandler {
 
-    /**
-     * Converts the given [response] to a subclass of [NetworkResponse] based on different conditions.
-     *
-     * If the server response is successful with:
-     * => a non-empty body -> NetworkResponse.Success<S, E>
-     * => an empty body (and [successBodyType] is Unit) -> NetworkResponse.Success<Unit, E>
-     * => an empty body (and [successBodyType] is not Unit) -> NetworkResponse.ServerError<E>
-     *
-     * @param response Retrofit's response object supplied to the call adapter
-     * @param successBodyType A [Type] representing the success body
-     * @param errorConverter A retrofit converter to convert the error body into the error response type (E)
-     * @param S The success body type generic parameter
-     * @param E The error body type generic parameter
-     */
-    fun <S : Any, E : Any> handle(
-        response: Response<S>,
-        successBodyType: Type,
-        errorConverter: Converter<ResponseBody, E>
-    ): NetworkResponse<S, E> {
-        val body = response.body()
-        val headers = response.headers()
-        val code = response.code()
-        val errorBody = response.errorBody()
+  /**
+   * Converts the given [response] to a subclass of [NetworkResponse] based on different conditions.
+   *
+   * If the server response is successful with:
+   * => a non-empty body -> NetworkResponse.Success<S, E>
+   * => an empty body (and [successBodyType] is Unit) -> NetworkResponse.Success<Unit, E>
+   * => an empty body (and [successBodyType] is not Unit) -> NetworkResponse.ServerError<E>
+   *
+   * @param response Retrofit's response object supplied to the call adapter
+   * @param successBodyType A [Type] representing the success body
+   * @param errorConverter A retrofit converter to convert the error body into the error response type (E)
+   * @param S The success body type generic parameter
+   * @param E The error body type generic parameter
+   */
+  fun <S : Any, E : Any> handle(
+      response: Response<S>,
+      successBodyType: Type,
+      errorConverter: Converter<ResponseBody, E>
+  ): NetworkResponse<S, E> {
+    val body = response.body()
+    val headers = response.headers()
+    val code = response.code()
+    val errorBody = response.errorBody()
 
-        return if (response.isSuccessful) {
-            if (body != null) {
-                NetworkResponse.Success(body, headers, code)
-            } else {
-                // Special case: If the response is successful and the body is null, return a successful response
-                // if the service method declares the success body type as Unit. Otherwise, return a server error
-                if (successBodyType == Unit::class.java) {
-                    @Suppress("UNCHECKED_CAST")
-                    NetworkResponse.Success(Unit, headers, code) as NetworkResponse<S, E>
-                } else {
-                    NetworkResponse.ServerError(null, code, headers)
-                }
-            }
+    return if (response.isSuccessful) {
+      if (body != null) {
+        NetworkResponse.Success(body, headers, code)
+      } else {
+        // Special case: If the response is successful and the body is null, return a successful response
+        // if the service method declares the success body type as Unit. Otherwise, return a server error
+        if (successBodyType == Unit::class.java) {
+          @Suppress("UNCHECKED_CAST")
+          NetworkResponse.Success(Unit, headers, code) as NetworkResponse<S, E>
         } else {
-            val networkResponse: NetworkResponse<S, E> = try {
-                val convertedBody = errorConverter.convert(errorBody)
-                NetworkResponse.ServerError(convertedBody, code, headers)
-            } catch (ex: Exception) {
-                NetworkResponse.UnknownError(ex)
-            }
-            networkResponse
+          NetworkResponse.ServerError(null, code, headers)
         }
+      }
+    } else {
+      val networkResponse: NetworkResponse<S, E> = try {
+        val convertedBody = if (errorBody == null) {
+          null
+        } else {
+          errorConverter.convert(errorBody)
+        }
+        NetworkResponse.ServerError(convertedBody, code, headers)
+      } catch (ex: Exception) {
+        NetworkResponse.UnknownError(ex, code = code, headers = headers)
+      }
+      networkResponse
     }
+  }
 
 }

src/test/kotlin/com/haroldadmin/cnradapter/MoshiApplicationTest.kt

@@ -25,6 +25,7 @@ internal data class GenericErrorResponse(val error: String)
 
 internal data class GenericErrorResponseInvalid(@Json(name = "errrorrrr") val error: String)
 
+@Suppress("DeferredIsResult")
 internal interface LaunchesService {
     @GET("launches/{flightNumber}")
     suspend fun launchForFlightNumber(
@@ -143,12 +144,32 @@ internal class MoshiApplicationTest: AnnotationSpec() {
         server.enqueue(MockResponse().apply {
             setBody(resourceFileContents("/falconsat_launch.json"))
             setResponseCode(200)
+            setHeader("test", "true")
         })
         val response = app.getLaunchWithFailure(validFlightNumber)
 
         response.shouldBeInstanceOf<NetworkResponse.UnknownError>()
         response as NetworkResponse.UnknownError
         response.error.shouldBeInstanceOf<JsonDataException>()
+        response.code shouldBe null
+        response.headers shouldBe null
+    }
+
+    @Test
+    fun shouldParseResponseCodeAndHeadersOfUnsuccessfulRequestWithInvalidBodyCorrectly() {
+        val app = TestApplication(service)
+        server.enqueue(MockResponse().apply {
+            setBody("""{ "message": "Too many requests!" }""")
+            setResponseCode(429)
+            setHeader("test", "true")
+        })
+        val response = app.getLaunchWithFailure(validFlightNumber)
+
+        response.shouldBeInstanceOf<NetworkResponse.UnknownError>()
+        response as NetworkResponse.UnknownError
+        response.error.shouldBeInstanceOf<JsonDataException>()
+        response.code shouldBe 429
+        response.headers!!["test"] shouldBe "true"
     }
 
     @Test