SSEDistributor.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
 * 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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 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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#ifndef MQTTBRIDGE_LIB_SSEDISTRIBUTOR_H
#define MQTTBRIDGE_LIB_SSEDISTRIBUTOR_H
 
namespace express {
    class Response;
}
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#include <chrono>
#include <core/timer/Timer.h>
#include <cstdint>
#include <list>
#include <memory>
#include <nlohmann/json_fwd.hpp>
#include <string>
 
#endif // DOXYGEN_SHOULD_SKIP_THIS
 
namespace mqtt::bridge::lib {
 
    class SSEDistributor {
    private:
        class EventReceiver {
        public:
            EventReceiver(const std::shared_ptr<express::Response>& response);
 
            ~EventReceiver();
 
            std::shared_ptr<express::Response> getResponse() const;
 
            bool operator==(const EventReceiver& other);
 
        private:
            std::weak_ptr<express::Response> response;
 
            core::timer::Timer heartbeatTimer;
        };
 
        class Event {
        public:
            Event(const std::string& data, const std::string& event, const std::string& id);
 
            Event(const Event&) = delete;
            Event(Event&&) = delete;
 
            Event& operator=(const Event&) = delete;
            Event& operator=(Event&&) = delete;
 
            const std::string& getData() const;
            const std::string& getEvent() const;
            const std::string& getId() const;
 
        private:
            std::string data;
            std::string event;
            std::string id;
        };
 
        SSEDistributor();
 
    public:
        static SSEDistributor& instance();
 
        SSEDistributor(const SSEDistributor&) = delete;
        SSEDistributor& operator=(const SSEDistributor&) = delete;
 
        SSEDistributor(SSEDistributor&&) = delete;
        SSEDistributor& operator=(SSEDistributor&&) = delete;
 
        ~SSEDistributor() = default;
 
        void addEventReceiver(const std::shared_ptr<express::Response>& response, const std::string& lastEventId);
 
        void bridgesStarting();
        void bridgesStarted();
 
        void bridgesStopping();
        void bridgesStopped();
 
        void bridgeDisabled(const std::string& bridgeName);
        void bridgeStarting(const std::string& bridgeName);
        void bridgeStarted(const std::string& bridgeName);
 
        void bridgeStopping(const std::string& bridgeName);
        void bridgeStopped(const std::string& bridgeName);
 
        void brokerDisabled(const std::string& bridgeName, const std::string& instanceName);
        void brokerConnecting(const std::string& bridgeName, const std::string& instanceName);
        void brokerConnected(const std::string& bridgeName, const std::string& instanceName);
 
        void brokerDisconnecting(const std::string& bridgeName, const std::string& instanceName);
        void brokerDisconnected(const std::string& bridgeName, const std::string& instanceName);
 
    private:
        static void sendEvent(const std::shared_ptr<express::Response>& response,
                              const std::string& data,
                              const std::string& event,
                              const std::string& id);
 
        static void sendJsonEvent(const std::shared_ptr<express::Response>& response,
                                  const nlohmann::json& json,
                                  const std::string& event = "",
                                  const std::string& id = "");
        void sendEvent(const std::string& data, const std::string& event = "", const std::string& id = "");
        void sendJsonEvent(const nlohmann::json& json, const std::string& event = "", const std::string& id = "");
 
        static std::string timePointToString(const std::chrono::time_point<std::chrono::system_clock>& timePoint);
        static std::string
        durationToString(const std::chrono::time_point<std::chrono::system_clock>& bevore,
                         const std::chrono::time_point<std::chrono::system_clock>& later = std::chrono::system_clock::now());
 
        std::string bridgesStartedAt() const;
 
        std::list<EventReceiver> eventReceiverList;
        std::chrono::time_point<std::chrono::system_clock> onlineSinceTimePoint;
        std::chrono::time_point<std::chrono::system_clock> bridgesStartTimePoint;
        uint64_t id = 0;
 
        std::list<Event> replayEvents;
    };
 
} // namespace mqtt::bridge::lib
 
#endif // MQTTBRIDGE_LIB_SSEDISTRIBUTOR_H