几步实现stm32上面移植mqtt

最近项目需要，stm32上面使用到mqtt了，百度了下，发现网上资料还是挺少的，虽然有几份相关的资料，下载下来之后，看到了mqtt的底层代码竟然还有错误，这个问题导致了我后面一直调试不通，后来，我直接从官方下载了mqtt的源码用比较器比较后找到了原因，最后果断将官方的mqtt底层代码移植上来，mqtt的发布还是比较顺利，订阅虽然可以收到消息，但是由于没有移植os，发布消息时，订阅接受有时无法收到消息，这个还在优化，我使用的是stm32f103c8t6平台+w5500.其实只要带以太网接口就行。首先我们从mqtt官方下载源码
http://git.eclipse.org/c/paho/org.eclipse.paho.mqtt.embedded-c.git/refs/
下载后将MQTTPacket下面的src文件都加入到自己的MDK工程中。


如果采用W5500的话，最好先用官方的TCP例子将TCP调试通，而且能保证访问外网，可以借鉴下网上那个STM32F405+W5500的例子，我觉得那个还是挺好的，我也是主要借鉴了那个例子，不过我还是不太喜欢他把TCP的建立封装到mqtt里面，一开始我也是采用他那种方法，不过一直出错，后来我采用了状态机实现，先让TCP和mqtt服务器建立TCP连接在调用mqtt的连接，发布等API，这样比较好调试。调试的话，我采用的是下面那个页面调试的http://m2m.demos.ibm.com/mqttclient/#log

其实真正要你实现的mqtt接口，主要是transport.c里面的几个API
int transport_sendPacketBuffer(unsigned char* buf, int buflen)
{
return send(SOCK_MQTT,buf,buflen);
}
/**
* @brief×èè?·?ê??óê?TCP·t???÷·￠?íμ?êy?Y
* @parambuf êy?Y′?′￠ê×μ??·
* @paramcount êy?Y?o3???3¤?è
* @retval D?óú0±íê??óê?êy?Y꧰ü
*/
int transport_getdata(unsigned char* buf, int count)
{
return recv(SOCK_MQTT,buf,count);
}


/**
* @brief′ò?aò???socket2￠á??óμ?·t???÷
* @param?T
* @retval D?óú0±íê?′ò?a꧰ü
*/
int transport_open(void)
{
int32_t ret;
//D??¨ò???Socket2￠°ó?¨±?μ????ú5000
ret = socket(SOCK_MQTT,Sn_MR_TCP,4500,Sn_MR_ND);
if(ret != SOCK_OK){
printf("%d:Socket Errorrn",SOCK_MQTT);
}else{
printf("%d:Openedrn",SOCK_MQTT);
}

//á??óTCP·t???÷
ret = connect(SOCK_MQTT,domain_ip,1883);//???ú±?D??a1883
if(ret != SOCK_OK){
printf("%d:Socket Connect Errorrn",SOCK_MQTT);
}else{
printf("%d:Connectedrn",SOCK_MQTT);
}
return ret;
}
/**
* @brief1?±?socket
* @param?T
* @retval D?óú0±íê?1?±?꧰ü
*/
int transport_close(void)
{
close(SOCK_MQTT);
return 0;
}

以上的其实transport_open(void)我没调用，让状态机来实现了这步。
int mqtt_publish(char *pTopic,char *pMessage)
{
int32_t len,rc;
MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
unsigned char buf[200];
MQTTString topicString = MQTTString_initializer;
int msglen = strlen(pMessage);
int buflen = sizeof(buf);
data.clientID.cstring = "Client74925";
data.keepAliveInterval = 15;
data.cleansession = 1;
len = MQTTSerialize_connect(buf, buflen, &data); /* 1 */
topicString.cstring = pTopic;
len += MQTTSerialize_publish(buf + len, buflen - len, 0, 0, 0, 0, topicString, (unsigned char*)pMessage, msglen); /* 2 */
len += MQTTSerialize_disconnect(buf + len, buflen - len); /* 3 */
rc = transport_sendPacketBuffer(buf,len);
if (rc == len)
printf("Successfully publishednr");
else
printf("Publish failednr");
return 0;
}

=========================================

void do_tcp_client(void)
{
uint8 connect_State = 0;
uint16 len1;
switch(getSn_SR(SOCK_MQTT)) /*??è?socketμ?×′ì?*/
{
case SOCK_CLOSED: /*socket′|óú1?±?×′ì?*/
socket(SOCK_MQTT,Sn_MR_TCP,local_port++,Sn_MR_ND);
break;
case SOCK_INIT: /*socket′|óú3?ê??ˉ×′ì?*/
connect(SOCK_MQTT,domain_ip,1883); /*socketá??ó·t???÷*/
break;
case SOCK_ESTABLISHED: /*socket′|óúá??ó?¨á￠×′ì?*/
memset(buff,0,500);
#if 0
connect_State=mqtt_subscrib("planets/earth",buff);
if(connect_State)
{
printf("%s",buff);

}
#endif
if(heartbeatflag>=TIME_5S)
{
heartbeatflag=0;
mqtt_publish("planets/earth","firstName: Brett, lastName:McLaughlin,email:aaaa");
}
break;
case SOCK_CLOSE_WAIT: /*socket′|óúμè′y1?±?×′ì?*/
close(SOCK_MQTT);
break;

}
}
上面的发布我每5s发送一条消息，公司的电脑加密了，无法截图，只能copy下网页测试的数据
============================================================================
(06:23:57.487) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa(06:24:02.492) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa(06:24:02.810) >> [planets/earth][retained] Hello world!(06:24:02.810) Subscribed to [planets/earth][qos 0](06:24:07.501) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa(06:24:12.497) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa(06:24:17.490) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa(06:24:22.490) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa(06:24:27.491) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa(06:24:32.481) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa(06:24:37.490) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa(06:24:42.497) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa(06:24:47.491) >> [planets/earth] firstName: Brett, lastName:McLaughlin,email:aaaa
订阅消息的函数目前暂且不公布，主要是还在优化，其次我觉得有点鸡肋，以其误导大伙，还不如不公开～～～～～～～～～～～～，如果大伙觉得有意思，可以把mqtt的ping也加上去，如果实用的话，这个还需要加入很多容错机制～～～～～～～～～～～～