图解连接阿里云(二)使用Paho-MQTT(支持FreeRTOS版本、Linux版本)连接1MQTT测试服务器 2阿里云物联网平台

前沿提要：

MQTT是什么不知道？

看这一篇：https://www.cnblogs.com/happybirthdaytoyou/p/10362336.html

阿里云官网玩不转？

看这一篇： https://www.cnblogs.com/happybirthdaytoyou/p/14065294.html

不会用代码连接阿里云？

看这一篇：https://www.cnblogs.com/happybirthdaytoyou/p/14074606.html

Paho-MQTT

前往下载  https://gitee.com/mirrors/paho.mqtt.embedded-c?_from=gitee_search

我当前使用版本：

链接：https://pan.baidu.com/s/1pkUyD2mcQlQQur2GZHryCw
提取码：kcpo

0. 简介

Paho嵌入式C工程提供了以下三个子项目：

• MQTTPacket： 这里提供MQTT数据包的序列化与反序列化，以及部分辅助函数。
• 它们是高级库的基础，但也可以单独使用。主要取决于您对网络的读写，大概意思就是如果你对MQTT源码很熟悉，你可以直接使用MQTTPacket的接口。
• MQTTClient：  封装MQTTPacket生成的高级别C++客户端程序。
• MQTTClient-C：封装MQTTPacket生成的高级别C客户端程序。

• MQTTClient-C中包含：

  ├──  CMakeLists.txt
  ├──  samples
  │   ├──  CMakeLists.txt
  │   ├──  FreeRTOS
  │   └──  linux
  ├──  src
  │   ├──  CMakeLists.txt
  │   ├──  FreeRTOS
  │   ├──  MQTTClient.c
  │   ├──  MQTTClient.h
  │   ├──  cc3200
  │   └──  linux
  └──  test
      ├──  CMakeLists.txt
      └──  test1.c

  • samples目录提供FreeRTOS和linux两个例程，分别支持FreeRTOS和Linux系统。
  • src目录提供MQTTClient的代码实现能力，以及用于移植到FreeRTOS、cc3200和Linux的网络驱动。

代码编译方法

mkdir mybuild
cd mybuild
cmake ..
make

添加两个源文件，然后修改CMakeLists.txt

修改后的CMakeLists.txt：

add_executable(
  aiot_c_demo
  aiot_c_demo.c
  aiot_mqtt_sign.c
)

target_link_libraries(aiot_c_demo paho-embed-mqtt3cc paho-embed-mqtt3c)
target_include_directories(aiot_c_demo PRIVATE "../../src" "../../src/linux")
target_compile_definitions(aiot_c_demo PRIVATE MQTTCLIENT_PLATFORM_HEADER=MQTTLinux.h)

1. 连接MQTT测试服务器

使用的测试服务器：

aiot_c_demo.c  这是你主要编写的代码，你可以参考我下面的

/**
这个例子是发布消息到MQTT测试服务器 test.mosquitto.org 上去。
我windows上的MQTT客户端软件订阅了该主题，所以可以收到这里发送的消息。
**/

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

#define ADDRESS     "test.mosquitto.org"    // MQTT Test Server For Free
#define PORT         1883
#define CLIENTID                          // 客户端ID

const char *subTopic = "/publish/TEST/111";
const char *pubTopic = "/publish/TEST/000";

char clientId[150] = {0};
char username[65]  = {0};
char password[65]  = {0};

unsigned char sendbuf[1000];
unsigned char readbuf[1000];

void messageArrived(MessageData* md)
{
    MQTTMessage* message = md->message;

    printf("\nIOT Cloud Message Arrived! \n");
    printf("%.*s\n", md->topicName->lenstring.len,  md->topicName->lenstring.data);
    printf("%.*s\n\n", (int)message->payloadlen,     (char*)message->payload);
}

int main(int argc, char* argv[])
{
    Network net;
    MQTTClient client;
    char *host = ADDRESS;
    short port = PORT;

    /* network init and establish network  */
    NetworkInit(&net);

    int rc = NetworkConnect(&net, host, port);
    if(!rc){
        printf("\nNetworkConnect Success \n");
    }
    else{
        printf("\nNetworkConnect ERR \n\n");
    }

    /**************MQTT Client Init***************/
    MQTTClientInit(&client, &net, 1000, sendbuf, sizeof(sendbuf), readbuf, sizeof(readbuf));
    /* set the default message handler */
    client.defaultMessageHandler = messageArrived;

    /**************MQTTConnect***************/
    /* set mqtt connect parameter */
    MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
    data.willFlag = 0;
    //data.MQTTVersion = 3; 版本号不要指定，要不然连接服务器(执行MQTTConnect时)会返回失败
    data.clientID.cstring = clientId; //clientId;
    data.username.cstring = username;
    data.password.cstring = password;
    data.keepAliveInterval = 60;
    data.cleansession = 1;
    printf("......Try to Connect to %s %d, ......\n", host, port);

    rc = MQTTConnect(&client, &data);
    if(!rc)
        printf("MQTTConnect %d, Connect MQTT IoT Cloud Success!\n", rc);
    else
        printf("MQTTConnect %d, Connect ERR!\n", rc);

    /**************MQTTSubscribe***************/
    rc = MQTTSubscribe(&client, subTopic, 1, messageArrived);
    if(!rc)
        printf("MQTTSubscribe %d, MQTTSubscribe MQTT IoT Cloud Success!\n", rc);
    else
        printf("MQTTSubscribe %d, MQTTSubscribe ERR!\n", rc);

    /**************MQTTPublish***************/
    #define mqttdata "hello mqtt"

    MQTTMessage msg = {
        QOS1,
        1,             //  retained .
        0,
        0,            //  id
        mqttdata,
        strlen(mqttdata),
    };
    msg.id++;
    rc = MQTTPublish(&client, pubTopic, &msg);
    if(!rc)
        printf("MQTTPublish %d, id = %d MQTTPublish MQTT IoT Cloud Success! \n", rc, msg.id);
    else
        printf("MQTTPublish %d, MQTTPublish ERR!\n", rc);

    while(1){

        MQTTYield(&client, 1000); // 在需要接收数据时, 都需要主动调用该函数
        printf("---1s--- \n ");

    }

    return rc;
}

aiot_mqtt_sign.c 暂时为空文件即可， 连接阿里云时才会使用到。

先填好通信猫软件上的参数

注意，这里填写的发布和订阅的主题是和aiot_c_demo.c内的发布订阅的主题对应的。 MQTT，依靠主题来建立不同客户端的关联。

PS：通信猫软件下载地址

 

ubuntu内编译程序，准备运行

运行结果:

2. 连接阿里云物联网平台

这里会使用到aiot_mqtt_sign.c

aiot_mqtt_sign.c加上内容吧， 赋值黏贴拿去使用即可，这里面的代码可以不用关心，主要是提供一个计算密码的功能函数：

/*
 * Copyright (C) 2015-2019 Alibaba Group Holding Limited
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>

#define PRODUCTKEY_MAXLEN           (20)
#define DEVICENAME_MAXLEN           (32)
#define DEVICESECRET_MAXLEN         (64)

#define SIGN_SOURCE_MAXLEN          (200)
#define CLIENTID_MAXLEN             (150)
#define USERNAME_MAXLEN             (64)
#define PASSWORD_MAXLEN             (65)

#define TIMESTAMP_VALUE             "2524608000000"
#define MQTT_CLINETID_KV            "|timestamp=2524608000000,_v=paho-c-1.0.0,securemode=3,signmethod=hmacsha256,lan=C|"

static void utils_hmac_sha256(const uint8_t *msg, uint32_t msg_len, const uint8_t *key, uint32_t key_len, uint8_t output[32]);

static void _hex2str(uint8_t *input, uint16_t input_len, char *output)
{
    char *zEncode = "0123456789ABCDEF";
    int i = 0, j = 0;

    for (i = 0; i < input_len; i++) {
        output[j++] = zEncode[(input[i] >> 4) & 0xf];
        output[j++] = zEncode[(input[i]) & 0xf];
    }
}

int aiotMqttSign(const char *productKey, const char *deviceName, const char *deviceSecret,
                     char clientId[150], char username[64], char password[65])
{
    char deviceId[PRODUCTKEY_MAXLEN + DEVICENAME_MAXLEN + 2] = {0};
    char macSrc[SIGN_SOURCE_MAXLEN] = {0};
    uint8_t macRes[32] = {0};
    int res;

    /* check parameters */
    if (productKey == NULL || deviceName == NULL || deviceSecret == NULL ||
        clientId == NULL || username == NULL || password == NULL) {
        return -1;
    }
    if ((strlen(productKey) > PRODUCTKEY_MAXLEN) || (strlen(deviceName) > DEVICENAME_MAXLEN) ||
        (strlen(deviceSecret) > DEVICESECRET_MAXLEN)) {
        return -1;
    }

    /* setup deviceId */
    memcpy(deviceId, deviceName, strlen(deviceName));
    memcpy(deviceId + strlen(deviceId), "&", strlen("&"));
    memcpy(deviceId + strlen(deviceId), productKey, strlen(productKey));

    /* setup clientid */
    memcpy(clientId, deviceId, strlen(deviceId));
    memcpy(clientId + strlen(deviceId), MQTT_CLINETID_KV, strlen(MQTT_CLINETID_KV));
    memset(clientId + strlen(deviceId) + strlen(MQTT_CLINETID_KV), 0, 1);

    /* setup username */
    memcpy(username, deviceId, strlen(deviceId));
    memset(username + strlen(deviceId), 0, 1);

    /* setup password */
    memcpy(macSrc, "clientId", strlen("clientId"));
    memcpy(macSrc + strlen(macSrc), deviceId, strlen(deviceId));
    memcpy(macSrc + strlen(macSrc), "deviceName", strlen("deviceName"));
    memcpy(macSrc + strlen(macSrc), deviceName, strlen(deviceName));
    memcpy(macSrc + strlen(macSrc), "productKey", strlen("productKey"));
    memcpy(macSrc + strlen(macSrc), productKey, strlen(productKey));
    memcpy(macSrc + strlen(macSrc), "timestamp", strlen("timestamp"));
    memcpy(macSrc + strlen(macSrc), TIMESTAMP_VALUE, strlen(TIMESTAMP_VALUE));

    utils_hmac_sha256((uint8_t *)macSrc, strlen(macSrc), (uint8_t *)deviceSecret,
                      strlen(deviceSecret), macRes);

    memset(password, 0, PASSWORD_MAXLEN);
    _hex2str(macRes, sizeof(macRes), password);
    return 0;
}

/******************************
 * hmac-sha256 implement below
 ******************************/
#define SHA256_KEY_IOPAD_SIZE   (64)
#define SHA256_DIGEST_SIZE      (32)

/**
 * \brief          SHA-256 context structure
 */
typedef struct {
    uint32_t total[2];          /*!< number of bytes processed  */
    uint32_t state[8];          /*!< intermediate digest state  */
    unsigned char buffer[64];   /*!< data block being processed */
    int is224;                  /*!< 0 => SHA-256, else SHA-224 */
} iot_sha256_context;

typedef union {
    char sptr[8];
    uint64_t lint;
} u_retLen;

/*
 * 32-bit integer manipulation macros (big endian)
 */
#ifndef GET_UINT32_BE
#define GET_UINT32_BE(n,b,i)                                \
    do {                                                    \
        (n) = ( (uint32_t) (b)[(i)    ] << 24 )             \
              | ( (uint32_t) (b)[(i) + 1] << 16 )           \
              | ( (uint32_t) (b)[(i) + 2] <<  8 )           \
              | ( (uint32_t) (b)[(i) + 3]       );          \
    } while( 0 )
#endif

#ifndef PUT_UINT32_BE
#define PUT_UINT32_BE(n,b,i)                                \
    do {                                                    \
        (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
        (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
        (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
        (b)[(i) + 3] = (unsigned char) ( (n)       );       \
    } while( 0 )
#endif

static void utils_sha256_zeroize(void *v, uint32_t n)
{
    volatile unsigned char *p = v;
    while (n--) {
        *p++ = 0;
    }
}

void utils_sha256_init(iot_sha256_context *ctx)
{
    memset(ctx, 0, sizeof(iot_sha256_context));
}

void utils_sha256_free(iot_sha256_context *ctx)
{
    if (NULL == ctx) {
        return;
    }

    utils_sha256_zeroize(ctx, sizeof(iot_sha256_context));
}

void utils_sha256_starts(iot_sha256_context *ctx)
{
    int is224 = 0;
    ctx->total[0] = 0;
    ctx->total[1] = 0;

    if (is224 == 0) {
        /* SHA-256 */
        ctx->state[0] = 0x6A09E667;
        ctx->state[1] = 0xBB67AE85;
        ctx->state[2] = 0x3C6EF372;
        ctx->state[3] = 0xA54FF53A;
        ctx->state[4] = 0x510E527F;
        ctx->state[5] = 0x9B05688C;
        ctx->state[6] = 0x1F83D9AB;
        ctx->state[7] = 0x5BE0CD19;
    }

    ctx->is224 = is224;
}

static const uint32_t K[] = {
    0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5,
    0x3956C25B, 0x59F111F1, 0x923F82A4, 0xAB1C5ED5,
    0xD807AA98, 0x12835B01, 0x243185BE, 0x550C7DC3,
    0x72BE5D74, 0x80DEB1FE, 0x9BDC06A7, 0xC19BF174,
    0xE49B69C1, 0xEFBE4786, 0x0FC19DC6, 0x240CA1CC,
    0x2DE92C6F, 0x4A7484AA, 0x5CB0A9DC, 0x76F988DA,
    0x983E5152, 0xA831C66D, 0xB00327C8, 0xBF597FC7,
    0xC6E00BF3, 0xD5A79147, 0x06CA6351, 0x14292967,
    0x27B70A85, 0x2E1B2138, 0x4D2C6DFC, 0x53380D13,
    0x650A7354, 0x766A0ABB, 0x81C2C92E, 0x92722C85,
    0xA2BFE8A1, 0xA81A664B, 0xC24B8B70, 0xC76C51A3,
    0xD192E819, 0xD6990624, 0xF40E3585, 0x106AA070,
    0x19A4C116, 0x1E376C08, 0x2748774C, 0x34B0BCB5,
    0x391C0CB3, 0x4ED8AA4A, 0x5B9CCA4F, 0x682E6FF3,
    0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208,
    0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2,
};

#define  SHR(x,n) ((x & 0xFFFFFFFF) >> n)
#define ROTR(x,n) (SHR(x,n) | (x << (32 - n)))

#define S0(x) (ROTR(x, 7) ^ ROTR(x,18) ^  SHR(x, 3))
#define S1(x) (ROTR(x,17) ^ ROTR(x,19) ^  SHR(x,10))

#define S2(x) (ROTR(x, 2) ^ ROTR(x,13) ^ ROTR(x,22))
#define S3(x) (ROTR(x, 6) ^ ROTR(x,11) ^ ROTR(x,25))

#define F0(x,y,z) ((x & y) | (z & (x | y)))
#define F1(x,y,z) (z ^ (x & (y ^ z)))

#define R(t)                                        \
    (                                               \
            W[t] = S1(W[t -  2]) + W[t -  7] +      \
                   S0(W[t - 15]) + W[t - 16]        \
    )

#define P(a,b,c,d,e,f,g,h,x,K)                      \
    {                                               \
        temp1 = h + S3(e) + F1(e,f,g) + K + x;      \
        temp2 = S2(a) + F0(a,b,c);                  \
        d += temp1; h = temp1 + temp2;              \
    }

void utils_sha256_process(iot_sha256_context *ctx, const unsigned char data[64])
{
    uint32_t temp1, temp2, W[64];
    uint32_t A[8];
    unsigned int i;

    for (i = 0; i < 8; i++) {
        A[i] = ctx->state[i];
    }

    for (i = 0; i < 64; i++) {
        if (i < 16) {
            GET_UINT32_BE(W[i], data, 4 * i);
        } else {
            R(i);
        }

        P(A[0], A[1], A[2], A[3], A[4], A[5], A[6], A[7], W[i], K[i]);

        temp1 = A[7];
        A[7] = A[6];
        A[6] = A[5];
        A[5] = A[4];
        A[4] = A[3];
        A[3] = A[2];
        A[2] = A[1];
        A[1] = A[0];
        A[0] = temp1;
    }

    for (i = 0; i < 8; i++) {
        ctx->state[i] += A[i];
    }
}
void utils_sha256_update(iot_sha256_context *ctx, const unsigned char *input, uint32_t ilen)
{
    size_t fill;
    uint32_t left;

    if (ilen == 0) {
        return;
    }

    left = ctx->total[0] & 0x3F;
    fill = 64 - left;

    ctx->total[0] += (uint32_t) ilen;
    ctx->total[0] &= 0xFFFFFFFF;

    if (ctx->total[0] < (uint32_t) ilen) {
        ctx->total[1]++;
    }

    if (left && ilen >= fill) {
        memcpy((void *)(ctx->buffer + left), input, fill);
        utils_sha256_process(ctx, ctx->buffer);
        input += fill;
        ilen  -= fill;
        left = 0;
    }

    while (ilen >= 64) {
        utils_sha256_process(ctx, input);
        input += 64;
        ilen  -= 64;
    }

    if (ilen > 0) {
        memcpy((void *)(ctx->buffer + left), input, ilen);
    }
}

static const unsigned char sha256_padding[64] = {
    0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

void utils_sha256_finish(iot_sha256_context *ctx, uint8_t output[32])
{
    uint32_t last, padn;
    uint32_t high, low;
    unsigned char msglen[8];

    high = (ctx->total[0] >> 29)
           | (ctx->total[1] <<  3);
    low  = (ctx->total[0] <<  3);

    PUT_UINT32_BE(high, msglen, 0);
    PUT_UINT32_BE(low,  msglen, 4);

    last = ctx->total[0] & 0x3F;
    padn = (last < 56) ? (56 - last) : (120 - last);

    utils_sha256_update(ctx, sha256_padding, padn);
    utils_sha256_update(ctx, msglen, 8);

    PUT_UINT32_BE(ctx->state[0], output,  0);
    PUT_UINT32_BE(ctx->state[1], output,  4);
    PUT_UINT32_BE(ctx->state[2], output,  8);
    PUT_UINT32_BE(ctx->state[3], output, 12);
    PUT_UINT32_BE(ctx->state[4], output, 16);
    PUT_UINT32_BE(ctx->state[5], output, 20);
    PUT_UINT32_BE(ctx->state[6], output, 24);

    if (ctx->is224 == 0) {
        PUT_UINT32_BE(ctx->state[7], output, 28);
    }
}

void utils_sha256(const uint8_t *input, uint32_t ilen, uint8_t output[32])
{
    iot_sha256_context ctx;

    utils_sha256_init(&ctx);
    utils_sha256_starts(&ctx);
    utils_sha256_update(&ctx, input, ilen);
    utils_sha256_finish(&ctx, output);
    utils_sha256_free(&ctx);
}

static void utils_hmac_sha256(const uint8_t *msg, uint32_t msg_len, const uint8_t *key, uint32_t key_len, uint8_t output[32])
{
    iot_sha256_context context;
    uint8_t k_ipad[SHA256_KEY_IOPAD_SIZE];    /* inner padding - key XORd with ipad  */
    uint8_t k_opad[SHA256_KEY_IOPAD_SIZE];    /* outer padding - key XORd with opad */
    int32_t i;

    if ((NULL == msg) || (NULL == key) || (NULL == output)) {
        return;
    }

    if (key_len > SHA256_KEY_IOPAD_SIZE) {
        return;
    }

    /* start out by storing key in pads */
    memset(k_ipad, 0, sizeof(k_ipad));
    memset(k_opad, 0, sizeof(k_opad));
    memcpy(k_ipad, key, key_len);
    memcpy(k_opad, key, key_len);

    /* XOR key with ipad and opad values */
    for (i = 0; i < SHA256_KEY_IOPAD_SIZE; i++) {
        k_ipad[i] ^= 0x36;
        k_opad[i] ^= 0x5c;
    }

    /* perform inner SHA */
    utils_sha256_init(&context);                                      /* init context for 1st pass */
    utils_sha256_starts(&context);                                    /* setup context for 1st pass */
    utils_sha256_update(&context, k_ipad, SHA256_KEY_IOPAD_SIZE);     /* start with inner pad */
    utils_sha256_update(&context, msg, msg_len);                      /* then text of datagram */
    utils_sha256_finish(&context, output);                            /* finish up 1st pass */

    /* perform outer SHA */
    utils_sha256_init(&context);                              /* init context for 2nd pass */
    utils_sha256_starts(&context);                            /* setup context for 2nd pass */
    utils_sha256_update(&context, k_opad, SHA256_KEY_IOPAD_SIZE);    /* start with outer pad */
    utils_sha256_update(&context, output, SHA256_DIGEST_SIZE);     /* then results of 1st hash */
    utils_sha256_finish(&context, output);                       /* finish up 2nd pass */
}

aiot_c_demo.c 这是你主要编写的代码，你可以参考我下面的

#include <stdio.h>
#include <memory.h>
#include "MQTTClient.h"

#include <stdio.h>
#include <signal.h>
#include <sys/time.h>

#define Aliyun  

#define EXAMPLE_PRODUCT_KEY            "a11B0MP4tDp"
#define EXAMPLE_DEVICE_NAME            "1st_device_mqttfx"
#define EXAMPLE_DEVICE_SECRET          "04dfa2d5fe80a9d993e6c59d6523fe43"

/* declare the external function aiotMqttSign() */
extern int aiotMqttSign(const char *productKey, const char *deviceName, const char *deviceSecret,
                         char clientId[150], char username[65], char password[65]);

volatile int toStop = 0;

void cfinish(int sig)
{
    signal(SIGINT, NULL);
    toStop = 1;
}

/*-----------------------------------------------
    printf("%*s", 10, s);
    意思是输出字符串s，但至少占10个位置，不足的在字符串s左边补空格，这里等同于printf("%10s", s);
-----------------------------------------------*/
void messageArrived(MessageData* md)
{
    MQTTMessage* message = md->message;

    printf("\nmessageArrived!! \n");
    printf("%.*s\t", md->topicName->lenstring.len, md->topicName->lenstring.data);
    printf("%.*s\n", (int)message->payloadlen, (char*)message->payload);
}

/* main function */
int main(int argc, char** argv)
{
    int rc = 0;

    /* setup the buffer, it must big enough for aliyun IoT platform */
    unsigned char buf[1000];
    unsigned char readbuf[1000];

    Network n;
    MQTTClient c;

#ifdef Aliyun
    char *host = EXAMPLE_PRODUCT_KEY".iot-as-mqtt.cn-shanghai.aliyuncs.com";
    short port =  443;

    const char *subTopic = "/"EXAMPLE_PRODUCT_KEY"/"EXAMPLE_DEVICE_NAME"/service/property/set";
    const char *pubTopic = "/sys/"EXAMPLE_PRODUCT_KEY"/"EXAMPLE_DEVICE_NAME"/thing/event/property/post";

#else

    char *host = "47.105.141.172";        // "test.mosquitto.org";
    short port = 1883; 

    const char *subTopic = "guest/talk";  // "/publish/TEST/111";
    const char *pubTopic = "guest/talk";  // "/publish/TEST/000";

#endif

    /* invoke aiotMqttSign to generate mqtt connect parameters */
    char clientId[150] = {0};
    char username[65]  = {0};
    char password[65]  = {0};

#ifdef Aliyun
    if ((rc = aiotMqttSign(EXAMPLE_PRODUCT_KEY, EXAMPLE_DEVICE_NAME, EXAMPLE_DEVICE_SECRET, clientId, username, password) < 0)) {
        printf("aiotMqttSign -%0x4x\n", -rc);
        return -1;
    }
    printf("clientid: %s\n", clientId);
    printf("username: %s\n", username);
    printf("password: %s\n", password);

#endif

    signal(SIGINT, cfinish);
    signal(SIGTERM, cfinish);

    /* network init and establish network to aliyun IoT platform */
    NetworkInit(&n);
    rc = NetworkConnect(&n, host, port);
    printf("NetworkConnect %d\n", rc);

    /* init mqtt client */
    MQTTClientInit(&c, &n, 1000, buf, sizeof(buf), readbuf, sizeof(readbuf));

    /* set the default message handler */
    c.defaultMessageHandler = messageArrived;

    /* set mqtt connect parameter */
    MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
    data.willFlag = 0;
    //data.MQTTVersion = 3;  版本号不要指定，要不然连接服务器(执行MQTTConnect时)会返回失败
    data.clientID.cstring = clientId;
    data.username.cstring = username;
    data.password.cstring = password;
    data.keepAliveInterval = 60;
    data.cleansession = 1;
    printf("Connecting to %s %d\n", host, port);

    rc = MQTTConnect(&c, &data);
    if(!rc)
    printf("MQTTConnect %d, Connect aliyun IoT Cloud Success!\n", rc);

    printf("Subscribing to %s\n", subTopic);
    rc = MQTTSubscribe(&c, subTopic, 1, messageArrived);
    printf("MQTTSubscribe %d\n", rc);

    int cnt = 0;
    unsigned int msgid = 0;

    char mqttdata[] = {"{\"method\":\"thing.event.property.post\",\"id\":\"1371514638\",\"params\":{\"Humidity\":76},\"version\":\"1.0.0\"}"};
    printf("mqttdata==> %s\n\n", mqttdata);

    while (!toStop)
    {
        // MQTT_Yield会block住timeout的时间去尝试接收数据，直到timeout才会退出
        MQTTYield(&c, 1000); // 在需要接收数据时, 都需要主动调用该函数    

        if (++cnt % 20 == 0) { // every 5 seconds, will do this
            MQTTMessage msg = {
                QOS0,
                1, // 0 ?
                0,
                0,
                mqttdata,
                strlen(mqttdata),
            };
                   msg.id = ++msgid;
           rc = MQTTPublish(&c, pubTopic, &msg);
           printf("MQTTPublish %d, msgid %d\n", rc, msgid);
        }
    }

    printf("Stopping\n");

    MQTTDisconnect(&c);
    NetworkDisconnect(&n);

    return 0;
}

结果

.