retrofit / okhttp wrong serialization of ByteArray (toString()) in kotlin

[rowi1de]

Using Retrofit 2.11.0 and okhttp 4.12.0 in kotlin will end up in wrong sterilization of binary data as it will use toString() having the [] of the string representation in the body

  val okHttpClient =
        OkHttpClient
          .Builder()
          .addInterceptor(httpLoggingInterceptor())
          .build()
      val retrofit =
        Retrofit
          .Builder()
          .baseUrl(config.url)
          .client(okHttpClient)
         // FIXME should not be needed  .addConverterFactory(ByteArrayConverterFactory())
          .build()
      retrofit.create(ApiClient::class.java)



private fun httpLoggingInterceptor(): HttpLoggingInterceptor {
  val logger = LogManager.getLogger(ApiClient::class.java)
  val logging = HttpLoggingInterceptor { logger.info(it) }
  logging.setLevel(HttpLoggingInterceptor.Level.BODY)
  logging.redactHeader("Authorization")
  logging.redactHeader("x-api-key")
  return logging
}

interface ApiClient {
  @POST("//binary")
  @Headers("Content-Type: application/octet-stream")
  fun binary(
  ): Call<ResponseBody>

// the workaround
class ByteArrayConverterFactory : Converter.Factory() {
  override fun requestBodyConverter(
    type: Type,
    parameterAnnotations: Array<Annotation>,
    methodAnnotations: Array<Annotation>,
    retrofit: Retrofit,
  ): Converter<ByteArray, RequestBody>? {
    if (type == ByteArray::class.java) {
      return Converter { value ->
        RequestBody.create(
          "application/octet-stream".toMediaTypeOrNull(),
          value,
        )
      }
    }
    return null
  }

  override fun responseBodyConverter(
    type: Type,
    annotations: Array<Annotation>,
    retrofit: Retrofit,
  ): Converter<ResponseBody, ByteArray>? {
    if (type == ByteArray::class.java) {
      return Converter { value ->
        value.use { it.bytes() }
      }
    }
    return null
  }
}