transport.hpp

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#pragma once
 
 
#include <conduit/bus.hpp>
#include <conduit/envelope.hpp>
#include <conduit/exception.hpp>
#include <conduit/listener.hpp>
#include <conduit/serialization.hpp>
#include <conduit/transport.hpp>
 
#include <chrono>
#include <cstdint>
#include <memory>
#include <optional>
#include <string>
 
namespace conduit::mqtt {
 
class MqttError : public conduit::TransportError {
public:
    using conduit::TransportError::TransportError;
};
 
enum class Format : std::uint8_t { Json, Cbor };
 
struct TlsConfig {
    std::string ca_file;
    std::optional<std::string> cert_file;
    std::optional<std::string> key_file;
    bool verify_peer = true;
};
 
struct Config {
    std::string url;        // "tcp://host:1883" or "ssl://host:8883"
    std::string client_id;  // empty -> generated from ULID
    std::optional<std::string> username;
    std::optional<std::string> password;
    std::optional<TlsConfig> tls;
    int qos = 1;  // 0/1/2
    bool clean_session = true;
    std::chrono::seconds keep_alive{60};
    std::chrono::seconds connect_timeout{10};
 
    std::string topic = "conduit/envelope";
 
    Format format = Format::Cbor;
};
 
class Transport : public conduit::Transport {
public:
    explicit Transport(Config config, std::shared_ptr<EventRegistry> registry = {});
 
    Transport(const Transport&) = delete;
    Transport& operator=(const Transport&) = delete;
    Transport(Transport&&) = delete;
    Transport& operator=(Transport&&) = delete;
 
    ~Transport() override;
 
    [[nodiscard]] TransportScope scope() const noexcept override {
        return TransportScope::Remote;
    }
 
    // Overrides `attach_with_sink`; the base `attach(Bus&)` default builds a
    // bus-default sink and delegates here, so wrapping with FilteredTransport
    // (which calls `attach_with_sink` directly) works without any extra glue.
    void attach_with_sink(Bus& bus, InboundSink sink) override;
    void detach() noexcept override;
 
    void dispatch(const EventEnvelopeView& v) override;
    void flush() override;
 
    [[nodiscard]] bool is_connected() const noexcept;
 
private:
    struct Impl;
    std::unique_ptr<Impl> impl_;
};
 
}  // namespace conduit::mqtt