How to map a http 200 with a nested status code of 400?

[ColtonIdle]

I have a response that comes back as an http 200 with the following body

{
  "status": "error",
  "code": 404,
}

This actually goes through the success case of my when statement when using eitherNet. According to the docs I think I want to use this snippet

@GET("/")
suspend fun getData(): ApiResult<SuccessResponse, ErrorResponse>

// In your own converter factory.
class ErrorConverterFactory : Converter.Factory() {
  override fun responseBodyConverter(
    type: Type,
    annotations: Array<out Annotation>,
    retrofit: Retrofit
  ): Converter<ResponseBody, *>? {
    // This returns a `@ResultType` instance that can be used to get the error type via toType()
    val (errorType, nextAnnotations) = annotations.errorType() ?: return null
    return ResponseBodyConverter(errorType.toType())
  }

  class ResponseBodyConverter(
    private val errorType: Type
  ) : Converter<ResponseBody, *> {
    override fun convert(value: ResponseBody): String {
      if (value.isErrorType()) {
        val errorResponse = ...
        throw ApiException(errorResponse)
      } else {
        return SuccessResponse(...)
      }
    }
  }
}

but I'm honestly not sure how best to peak into the json to see if it has a code 404. I'd appreciate any pointers. Thanks

[julioromano]

My case is slightly different: It's an API that always returns 200 with a fixed response body structure: when the status field is 0 it's an error, otherwise it's a success.
I made it work this way:

class MyErrorConverter(
    private val moshi: Moshi,
) : Converter.Factory() {
    override fun responseBodyConverter(
        type: Type,
        annotations: Array<out Annotation>,
        retrofit: Retrofit
    ): Converter<ResponseBody, *>? {
        val (errorType, _) = annotations.errorType() ?: return null
        return ResponseBodyConverter(moshi, errorType.toType())
    }

    class ResponseBodyConverter(
        private val moshi: Moshi,
        private val errorType: Type,
    ) : Converter<ResponseBody, MySuccessResponse > {
        override fun convert(value: ResponseBody): MySuccessResponse {
            val response = moshi.adapter(MyApiResponse::class.java)
                .fromJson(value.source()) ?: throw ApiException(null)
            return if (response.status == 0L) {
                when (errorType) {
                    MyFailureResponse::class.java ->
                        throw ApiException(MyFailureResponse(response.result))

                    else -> throw ApiException(null)
                }
            } else {
                MySuccessResponse(response.result)
            }
        }
    }
}

private data class MyApiResponse(
    val status: Long,
    val result: String
)

Hope this helps.