AWS iot SDK（aws-iot-device-sdk-embedded-C）添加设备断电后上报离线状态的功能_sigv4-for-aws-iot-embedded-sdk

1.在ESP8266_RTOS_SDK\components\aws_iot\aws-iot-device-sdk-embedded-C\include\aws_iot_shadow_interface.h中添加如下代码：

typedef struct {
	ShadowConnectParameters_t scp;
	unsigned int 		magic;
	unsigned short 		topicLen;
	unsigned short 		msgLen;
	char 				topic[64];
	char 				msg[64];
} HLE_ShadowConnectParameters_t; 
 
#define HLE_LAST_WILL_MSG "{\"state\":{\"reported\":{\"firmwave\":{\"connected\":\"false\",\"socket\":\"null\",\"usb\":\"null\"}}}}"

2.在ESP8266_RTOS_SDK\components\aws_iot\aws-iot-device-sdk-embedded-C\src\aws_iot_shadow.c中添加如下代码：

修改 函数 aws_iot_shadow_connect：

	#if 0 //HLE modify
	ConnectParams.isWillMsgPresent = false;
	#else
	typedef struct {
		unsigned int 		magic;
		unsigned short 		topicLen;
		unsigned short 		msgLen;
		char 				topic[64];
		char 				msg[64];
	} HLE_LASTWILL_PARA;
 
	HLE_LASTWILL_PARA* hlp = (HLE_LASTWILL_PARA*)((void*)pParams+sizeof(ShadowConnectParameters_t));
	if(hlp->magic == 0x19750521)
	{
		ConnectParams.isWillMsgPresent = true;
		ConnectParams.will = iotMqttWillOptionsDefault;
		ConnectParams.will.pTopicName = hlp->topic;
		ConnectParams.will.topicNameLen =  hlp->topicLen;
		ConnectParams.will.pMessage = hlp->msg;
		ConnectParams.will.msgLen = hlp->msgLen;
		ConnectParams.keepAliveIntervalInSec = 10;//30;
	}
	else
	{
		ConnectParams.isWillMsgPresent = false;
	}
	
	#endif