如何使用cloudamqp用C语言验证paho mqtt订户客户端？

Question

我想将mqtt订户c客户端连接到cloudamqp，但不知道如何使用C程序进行身份验证？是否还有其他具有示例功能的C语言客户端。我正在使用linux。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "MQTTClient.h"

#define ADDRESS     "tcp://buck.rmq.cloudamqp.com:1883"
#define CLIENTID    "ExampleClientSub"
#define PAYLOAD     "Hello World!"
#define QOS         1
#define TIMEOUT     10000L
#define USERNAME    "sakhdjs"
#define PASSWORD    "B7JnaMNF2evJmWpT_WZn"

char TOPIC[12];



volatile MQTTClient_deliveryToken deliveredtoken;

void delivered(void *context, MQTTClient_deliveryToken dt)
{
    printf("Message with token value %d delivery confirmed\n", dt);
    deliveredtoken = dt;
}

int msgarrvd(void *context, char *topicName, int topicLen, MQTTClient_message *message)
{
    int i;
    char* payloadptr;

    printf("Message arrived\n");
    printf("     topic: %s\n", topicName);
    printf("   message: ");

    payloadptr = message->payload;
    for(i=0; i<message->payloadlen; i++)
    {
        putchar(*payloadptr++);
    }
    putchar('\n');
    MQTTClient_freeMessage(&message);
    MQTTClient_free(topicName);
    return 1;
}

void connlost(void *context, char *cause)
{
    printf("\nConnection lost\n");
    printf("     cause: %s\n", cause);
}

int main(int argc, char* argv[])
{
    MQTTClient client;
    MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
    int rc;
    int ch;
    printf("Enter toic name to subscribe ");
    scanf("%s", TOPIC);
    //printf("Enter host adderss with format like tcp://localhost:1883 ");
   // scanf("%s", ADDRESS);
   
    MQTTClient_create(&client, ADDRESS, CLIENTID,
        MQTTCLIENT_PERSISTENCE_NONE,NULL);
    conn_opts.keepAliveInterval = 20;
    conn_opts.cleansession = 1;

    MQTTClient_setCallbacks(client, NULL, connlost, msgarrvd, delivered);

    if ((rc = MQTTClient_connect(client, &conn_opts ,USERNAME,PASSWORD)) != MQTTCLIENT_SUCCESS)
    {
        printf("Failed to connect, return code %d\n", rc);
        exit(EXIT_FAILURE);
    }
    printf("Subscribing to topic %s\nfor client %s using QoS%d\n\n"
           "Press Q<Enter> to quit\n\n", TOPIC, CLIENTID, QOS);
    MQTTClient_subscribe(client, TOPIC, QOS);

    do 
    {
        ch = getchar();
    } while(ch!='Q' && ch != 'q');

    MQTTClient_unsubscribe(client, TOPIC);
    MQTTClient_disconnect(client, 10000);
    MQTTClient_destroy(&client);
    return rc;
}

如何使用paho mqtt订户进行连接并发布？为此还有其他C语言客户端吗？还是其他任何使用C语言的代码？

Answer 1

在将其传递给username功能之前，请在password结构中设置MQTTClient_connectOptions和MQTTClient_connect()字段。

MQTTClient_create(&client, ADDRESS, CLIENTID,
    MQTTCLIENT_PERSISTENCE_NONE,NULL);
conn_opts.keepAliveInterval = 20;
conn_opts.cleansession = 1;
conn_opts.username = USERNAME
conn_opts.password = PASSWORD