Function ParseSliceStepBody

Modules/RESTAPI/src/mitkRenderingController.cpp:946–977

* \brief Parse `{"step": N}` from a slice-PUT body. * * \param body Pre-parsed JSON body. * \param resourceContext Resource label embedded into the rejection when * `position` is present (e.g. "StdMulti * selected-slice", "MxN selected-slice"). Identifies * which slice resource produced the error.

   * \returns nullopt on success; an error fragment otherwise.
   */
  std::optional<std::string> ParseSliceStepBody(const nlohmann::json& body,
                                                std::string_view resourceContext,
                                                const std::string& positionHint,
                                                unsigned int& step)
  {
    if (!body.is_object())
      return "Request body must be a JSON object.";

    if (body.contains("position"))
      return std::string("'position' is not accepted on ") + std::string(resourceContext)
        + ". " + positionHint;

    for (auto it = body.begin(); it != body.end(); ++it)
    {
      if (it.key() != "step")
        return "Unknown field '" + it.key() + "'.";
    }

    if (!body.contains("step"))
      return "'step' field is required.";

    const auto& s = body["step"];
    if (!s.is_number_integer())
      return "'step' must be a non-negative integer.";

    const auto raw = s.get<long long>();
    if (raw < 0)
      return "'step' must be a non-negative integer.";

    step = static_cast<unsigned int>(raw);
    return std::nullopt;
  }

  nlohmann::json CameraStateToJson(const mitk::CameraState& s)
  {