JsonMappingReader.cpp

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/*
 * MQTTSuite - A lightweight MQTT Integration System
 * Copyright (C) Volker Christian <me@vchrist.at>
 *               2022, 2023, 2024, 2025
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <https://www.gnu.org/licenses/>.
 */
 
/*
 * MIT License
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * The above copyright notice and this permission notice shall be included in
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#include "JsonMappingReader.h"
 
#include "nlohmann/json-schema.hpp"
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#include <exception>
#include <fstream>
#include <log/Logger.h>
#include <nlohmann/json.hpp>
 
#endif
 
namespace mqtt::lib {
 
#include "mapping-schema.json.h" // definition of mappingJsonSchemaString
 
    nlohmann::json JsonMappingReader::mappingJsonSchema = nlohmann::json::parse(mappingJsonSchemaString);
 
    std::map<std::string, nlohmann::json> JsonMappingReader::mapFileJsons;
 
    nlohmann::json& JsonMappingReader::readMappingFromFile(const std::string& mapFilePath) {
        if (!mapFileJsons.contains(mapFilePath)) {
            if (!mapFilePath.empty()) {
                std::ifstream mapFile(mapFilePath);
 
                if (mapFile.is_open()) {
                    VLOG(1) << "MappingFilePath: " << mapFilePath;
 
                    try {
                        mapFile >> mapFileJsons[mapFilePath];
 
                        try {
                            const nlohmann::json_schema::json_validator validator(mappingJsonSchema);
 
                            try {
                                const nlohmann::json defaultPatch = validator.validate(mapFileJsons[mapFilePath]);
 
                                try {
                                    mapFileJsons[mapFilePath] = mapFileJsons[mapFilePath].patch(defaultPatch);
                                } catch (const std::exception& e) {
                                    VLOG(1) << e.what();
                                    VLOG(1) << "Patching JSON with default patch failed:\n" << defaultPatch.dump(4);
                                    mapFileJsons[mapFilePath].clear();
                                }
                            } catch (const std::exception& e) {
                                VLOG(1) << "  Validating JSON failed:\n" << mapFileJsons[mapFilePath].dump(4);
                                VLOG(1) << "    " << e.what();
                                mapFileJsons[mapFilePath].clear();
                            }
                        } catch (const std::exception& e) {
                            VLOG(1) << e.what();
                            VLOG(1) << "Setting root json mapping schema failed:\n" << mappingJsonSchema.dump(4);
                            mapFileJsons[mapFilePath].clear();
                        }
                    } catch (const std::exception& e) {
                        VLOG(1) << "JSON map file parsing failed: " << e.what() << " at " << mapFile.tellg();
                        mapFileJsons[mapFilePath].clear();
                    }
 
                    mapFile.close();
                } else {
                    VLOG(1) << "MappingFilePath: " << mapFilePath << " not found";
                }
            } else {
                VLOG(1) << "MappingFilePath empty";
            }
        }
 
        return mapFileJsons[mapFilePath];
    }
 
} // namespace mqtt::lib