【经验】Z3GatewayHost Mqtt 如何正确处理 string 类型上报数据？

EFR32MG多协议SoC芯片是 SILICON LABS 专门针对 IOT 推出的 ZigBee 方案，高达19.5dbm的发射功率，-102.7dbm的接收灵敏度，在业界内拥有最佳的RF射频性能，具有最全的Zigbee网络协议，被广泛应用在智能家居，工业控制等行业。

在开发 Zigbee Gateway Mqtt时，Gateway 需要将所有设备上报数据给到 Server 端，在现有的 Z3HostGatewayMqtt 工程中没有正确的处理 String Characteristic 类型的数据上报。

bool emberAfReportAttributesCallback(EmberAfClusterId clusterId,

                                     uint8_t * buffer,

                                     uint16_t bufLen)

{

    EmberEUI64 nodeEui64;

    EmberNodeId nodeId = emberAfCurrentCommand()->source;

    emberAfDeviceTableGetEui64FromNodeId(nodeId, nodeEui64);

    uint8_t * bufferTemp;

    uint8_t * bufferPtr = buffer;

    uint8_t i, bufferSize;

    if (bufLen == 0)

    {

        emberAfAppPrintln("Report attributes callback: zero length buffer");

        return false;

    }

    // Buffer [0] is low bits, Buffer [1] is high bits, Buffer [2] is dataType,

    // Buffer [3+] is data

    emberAfAppPrintln("Reporting attributes for cluster: 0x%2x", clusterId);

    for (i = 0; i < bufLen; )

    {

        // Get Length of Attribute Buffer

        bufferSize = emberAfGetDataSize(

                         bufferPtr[ATTRIBUTE_BUFFER_REPORT_DATA_TYPE]);

         //add by sven

#define ATTRIBUTE_BUFFER_REPORT_DATA_LENGTH 3

        if(bufferPtr[ATTRIBUTE_BUFFER_REPORT_DATA_TYPE] == 0x42)        // character string

        {

            bufferSize = bufferPtr[ATTRIBUTE_BUFFER_REPORT_DATA_LENGTH];

        }

        // Add 3 bytes for header size

        bufferSize += 3;

        //Copy buffer to attributeBufferI

        bufferTemp = (uint8_t*)malloc(bufferSize);

        memcpy(bufferTemp, bufferPtr, bufferSize);

        //add by sven

        if(bufferPtr[ATTRIBUTE_BUFFER_REPORT_DATA_TYPE] == 0x42)       // character string

        {

            memcpy(bufferTemp+3, bufferPtr+ATTRIBUTE_BUFFER_REPORT_DATA_LENGTH+1, bufferPtr[ATTRIBUTE_BUFFER_REPORT_DATA_LENGTH]);

        }

        // Set i to point to:

        // [attrLSB,attrMSB,dataT,buffer,nAttrLSB,nAttrMSB,nextDataT,nextBuffer]

        // [       ,       ,     , ..n  ,   X    ,        ,         ,  ..n     ]

        bufferPtr = bufferPtr + bufferSize;

        i = i + bufferSize;

        //add by sven

        if(bufferPtr[-bufferSize + ATTRIBUTE_BUFFER_REPORT_DATA_TYPE ] == 0x42) // character string

        {

            bufferPtr = bufferPtr +1;

            i = i +1;

        }

        emberAfAppPrintln("Reported attribute: 0x%02X%02X, Type: %02X",

                          bufferTemp[ATTRIBUTE_BUFFER_ATTRIBUTEID_HIGH_BITS],

                          bufferTemp[ATTRIBUTE_BUFFER_ATTRIBUTEID_LOW_BITS],

                          bufferTemp[ATTRIBUTE_BUFFER_REPORT_DATA_TYPE]);

        publishMqttAttributeReport(nodeEui64,

                                   clusterId,

                                   bufferTemp,

                                   bufferSize);

        free(bufferTemp);

    }

    return false;

}

修改过的处理函数增加了对 string 类型的判断及长度截取