json_util.h

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/******************************************************************************
 * Copyright 2017 The Apollo Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *****************************************************************************/
 
#pragma once
 
#include <string>
#include <vector>
 
#include "google/protobuf/message.h"
#include "nlohmann/json.hpp"
#include "absl/strings/str_split.h"
 
#include "cyber/common/log.h"
 
namespace apollo {
namespace common {
namespace util {
 
class JsonUtil {
 public:
  static nlohmann::json ProtoToTypedJson(
      const std::string &json_type, const google::protobuf::Message &proto);
 
  static nlohmann::json ProtoToJson(const google::protobuf::Message &proto);
 
  static bool GetString(const nlohmann::json &json, const std::string &key,
                        std::string *value);
 
  template <class T>
  static bool GetNumber(const nlohmann::json &json, const std::string &key,
                        T *value) {
    const auto iter = json.find(key);
    if (iter == json.end()) {
      AERROR << "The json has no such key: " << key;
      return false;
    }
    if (!iter->is_number()) {
      AERROR << "The value of json[" << key << "] is not a number";
      return false;
    }
    *value = *iter;
    return true;
  }
 
  static bool GetBoolean(const nlohmann::json &json, const std::string &key,
                         bool *value);
 
  static bool GetStringVector(const nlohmann::json &json,
                              const std::string &key,
                              std::vector<std::string> *value);
 
  static bool GetJsonByPath(const nlohmann::json &json,
                            const std::vector<std::string> &paths,
                            nlohmann::json *value);
 
  static bool GetStringByPath(const nlohmann::json &json,
                              const std::string &path, std::string *value);
 
  static bool GetBooleanByPath(const nlohmann::json &json,
                               const std::string &path, bool *value);
 
  template <class T>
  static bool GetNumberByPath(const nlohmann::json &json,
                              const std::string &path, T *value) {
    std::vector<std::string> paths = absl::StrSplit(path, '.');
    std::string key = paths.back();
    paths.pop_back();
    nlohmann::json upper_layer_json = json;
    for (auto &field : paths) {
      if (field.empty()) {
        AERROR << "Invalid path: " << path;
        return false;
      }
      const auto iter = upper_layer_json.find(field);
      if (iter == upper_layer_json.end()) {
        AERROR << "The json has no such key: " << field;
        return false;
      }
      upper_layer_json = *iter;
    }
    return GetNumber(upper_layer_json, key, value);
  }
};
 
}  // namespace util
}  // namespace common
}  // namespace apollo