mqtt_client.hpp

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#pragma once

#include "../stdlib/string.hpp"
#include "../connpool/connect_client.hpp"
#include "../stream/socket_stream.hpp"

namespace acl {

class mqtt_header;
class mqtt_message;

/**
 * mqtt communication class in sync mode, used by mqtt client or mqtt server.
 */
class ACL_CPP_API mqtt_client : public connect_client {
public:
        /**
         * used to construct one mqtt client for connecting one mqtt server.
         * @param addr {const char*} the mqtt server's addr with the format
         *  like ip|port or domain|port.
         * @param conn_timeout {int} the timeout for connecting mqtt server.
         * @param rw_timeout {int} the timeout for reading from mqtt connection.
         */
        mqtt_client(const char* addr, int conn_timeout = 10, int rw_timeout = 10);

        /**
         * used to construct one mqtt client for connecting mqtt server, or
         * receiving from mqtt client.
         * @param conn {acl::socket_stream&}
         */
        mqtt_client(acl::socket_stream& conn);

        ~mqtt_client(void);

        /**
         * send ont mqtt message to the peer mqtt.
         * @param message {mqtt_message&} the mqtt message to be sent, where
         *  some viriable method of the mesage will be called, so we can't add
         *  the const limit on it.
         * @return {bool} return true if sending successfully.
         */
        bool send(mqtt_message& message);

        /**
         * read mqtt data from mqtt connection and create the correspondingly
         * mqtt message object with the mqtt type from mqtt header.
         * @return {mqtt_message*} return NULL if reading error or data invalid.
         */
        mqtt_message* get_message(void);

public:
        /**
         * read mqtt header information from mqtt connection.
         * @param header {const mqtt_header&} will store the mqtt headeer info.
         * @return {bool} return true if reading successfully.
         */
        bool read_header(mqtt_header& header);

        /**
         * read mqtt body information from mqtt connection.
         * @param header {const mqtt_header&} used to parse mqtt body.
         * @param body {mqtt_message&} will store mqtt body info.
         * @return {bool} return true if reading successfully.
         */
        bool read_message(const mqtt_header& header, mqtt_message& body);

protected:
        // @override
        bool open(void);

private:
        string addr_;
        int conn_timeout_;
        int rw_timeout_;

        socket_stream* conn_;
        socket_stream* conn_internal_;
};

} // namespace acl