MQTT-Gateway/mqtt.c
2024-01-22 22:00:14 +01:00

74 lines
1.7 KiB
C

#include <stdio.h>
#include <errno.h>
#include <string.h>
// https://mosquitto.org/api/files/mosquitto-h.html
#include <mosquitto.h>
struct mosquitto *connectMqtt(char *user, char *pass)
{
int err;
struct mosquitto *mqtt;
err = mosquitto_lib_init();
if (err)
{
fprintf(stderr, "Error initalizing mosquitto lib (%d): %s\n", err, mosquitto_strerror(err));
return NULL;
}
mqtt = mosquitto_new(user, true, NULL);
if (mqtt == NULL)
{
fprintf(stderr, "Error creating mosquitto instance (%d): %s\n", errno, strerror(errno));
return NULL;
}
err = mosquitto_username_pw_set(mqtt, user, pass);
if (err)
{
fprintf(stderr, "Error setting username & password (%d): %s\n", err, mosquitto_strerror(err));
return NULL;
}
err = mosquitto_connect(mqtt, "openhab.sugarland.lan", 1883, 10);
if (err)
{
fprintf(stderr, "Error on connection of type ");
if (err == MOSQ_ERR_ERRNO)
{
fprintf(stderr, "system (%d): %s\n", errno, strerror(errno));
}
else
{
fprintf(stderr, "mosquitto (%d): %s\n", err, mosquitto_strerror(err));
}
return NULL;
}
return mqtt;
}
int sendMqtt(struct mosquitto *mqtt, char *topic, char *payload, int payloadLength)
{
int err;
err = mosquitto_publish(mqtt, NULL, topic, payloadLength, payload, 0, false);
if (err)
{
fprintf(stderr, "Error publishing message (%d): %s\n", err, mosquitto_strerror(err));
return -1;
}
else
{
return 0;
}
}
void disconnectMqtt(struct mosquitto *mqtt)
{
// ignore errors
mosquitto_disconnect(mqtt);
mosquitto_destroy(mqtt);
}