如何从IoT中心反序列化已传递给事件中心的事件？

Question

我正在处理与IoT Hub连接的EventHub的消息。我将尝试解释整个过程。

使用终端，将以下命令发送到部署在Azure上的IoT中心组件：

  curl --request POST \
    --url "https://${IOT_HUB}.azure-devices.net/devices/${DEVICE}/messages/events?api-version=2018-06-30" \
    --header "Accept: application/json" \
    --header "Authorization: ${SAS_TOKEN}" \
    --data "{ \"field1\" : \"12345\", \"field2\" : \"abcde\" }" \
    --verbose

[当Azure函数接收事件（curl-> IoT中心-> Event-hub

    @FunctionName("processSensorData")
    public void processSensorData(
            @EventHubTrigger(
                    name = "demo",
                    eventHubName = "", // blank because the value is included in the connection string
                    cardinality = Cardinality.ONE,
                    connection = "EventHubConnectionString")
                    String item,
            final ExecutionContext context) {

        context.getLogger().info("Event hub message received: " + item.toString());

我在控制台中收到以下消息：

    [
    {
       "id":"xxx",
       "topic":"/SUBSCRIPTIONS/xxx/RESOURCEGROUPS/xxxPROVIDERS/MICROSOFT.DEVICES/IOTHUBS/Txxxx",
       "subject":"devices/xxx",

   "eventType":"Microsoft.Devices.DeviceTelemetry",
   "eventTime":"2020-04-13T15:02:15.253Z",
   "data":{
      "properties":{

      },
      "systemProperties":{
         "iothub-content-type":"application/x-www-form-urlencoded",
         "iothub-content-encoding":"",
         "iothub-connection-device-id":"xxx",
         "iothub-connection-auth-method":"{\"scope\":\"device\",\"type\":\"sas\",\"issuer\":\"iothub\",\"acceptingIpFilterRule\":null}",
         "iothub-connection-auth-generation-id":"xxx",
         "iothub-enqueuedtime":"2020-04-13T15:02:15.253Z",
         "iothub-message-source":"Telemetry"
      },
      "body":"yyy"
   },
   "dataVersion":"",
   "metadataVersion":"1"
}]

但主体似乎已加密。

如何解码正文以返回原始请求？

"{ \"field1\" : \"12345\", \"field2\" : \"abcde\" }"

非常感谢

胡安·安东尼奥

Answer 1

正文是base64 URL编码的。您应该在代码中对其进行解码，然后解析出JSON对象。尝试使用以下代码进行解码：

  var base64EncodedBytes = System.Convert.FromBase64String(base64EncodedData);
  var jsonStr = System.Text.Encoding.UTF8.GetString(base64EncodedBytes);