MqttMapper.h

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/*
 * MQTTSuite - A lightweight MQTT Integration System
 * Copyright (C) Volker Christian <me@vchrist.at>
 *               2022, 2023, 2024, 2025, 2026
 *
 * 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
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 * 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
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#ifndef MQTTBROKER_LIB_MQTTMAPPER_H
#define MQTTBROKER_LIB_MQTTMAPPER_H
 
namespace iot::mqtt {
    class Topic;
} // namespace iot::mqtt
 
#include <iot/mqtt/packets/Publish.h>
#include <utils/Timeval.h>
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
namespace inja {
    class Environment;
}
 
#include <cstdint>
#include <list>
#include <nlohmann/json.hpp> // IWYU pragma: export
#include <string>
#include <utility>
#include <vector>
 
namespace nlohmann::json_schema {
    class json_validator;
    class basic_error_handler;
} // namespace nlohmann::json_schema
 
// IWYU pragma: no_include <nlohmann/json_fwd.hpp>
 
#endif // DOXYGEN_SHOULD_SKIP_THIS
 
namespace mqtt::lib {
 
    class MqttMapper {
    public:
        struct ScheduledPublish {
            utils::Timeval delay;
            iot::mqtt::packets::Publish publish;
        };
 
        using MappedPublishes = std::pair<std::vector<iot::mqtt::packets::Publish>, std::vector<ScheduledPublish>>;
 
        MqttMapper();
        MqttMapper(const MqttMapper&) = delete;
        MqttMapper& operator=(const MqttMapper&) = delete;
 
        virtual ~MqttMapper();
 
        static const std::string& getSchema();
 
        bool setMapping(nlohmann::json mappingJson); // can throw
        const nlohmann::json& getMapping() const;
 
        std::string dump();
 
        const nlohmann::json& getConnection() const;
 
        std::list<iot::mqtt::Topic> extractSubscriptions() const;
        MappedPublishes getMappings(const iot::mqtt::packets::Publish& publish);
 
        static const nlohmann::json validate(const nlohmann::json& json);
        static const nlohmann::json validate(const nlohmann::json& json, nlohmann::json_schema::basic_error_handler& err);
 
    private:
        static void
        extractSubscription(const nlohmann::json& topicLevelJson, const std::string& topic, std::list<iot::mqtt::Topic>& topicList);
        static void
        extractSubscriptions(const nlohmann::json& mappingJson, const std::string& topic, std::list<iot::mqtt::Topic>& topicList);
 
        nlohmann::json findMatchingTopicLevel(const nlohmann::json& topicLevel, const std::string& topic);
 
        void publishMappedTemplate(const nlohmann::json& templateMapping, nlohmann::json& json, MappedPublishes& mappedPublishes);
        void getTemplateMappings(const nlohmann::json& templateMapping,
                                 nlohmann::json& json,
                                 const iot::mqtt::packets::Publish& publish,
                                 MappedPublishes& mappedPublishes);
 
        static void publishMappedMessage(
            const std::string& topic, const std::string& message, uint8_t qoS, bool retain, double delay, MappedPublishes& mappedPublishes);
        static void publishMappedMessage(const nlohmann::json& staticMapping,
                                         const iot::mqtt::packets::Publish& publish,
                                         MappedPublishes& mappedPublishes);
        static void getStaticMappings(const nlohmann::json& staticMapping,
                                      const iot::mqtt::packets::Publish& publish,
                                      MappedPublishes& mappedPublishes);
 
        nlohmann::json mappingJson;
 
        std::list<void*> pluginHandles;
 
        inja::Environment* injaEnvironment; // We need it as pointer as it must be removed befor unloading the plugin libraries
 
        static const nlohmann::json_schema::json_validator validator;
 
        static const std::string mappingJsonSchemaString;
    };
 
} // namespace mqtt::lib
 
#endif // MQTTBROKER_LIB_MQTTMAPPER_H