extract json with nodered

问题

I want to extract json part in a message with node red

I receive the message in node red but I can't extract the data exemple of a message:

POST / HTTP/1.1

Host: xxx.xx.xxx.5:9000

User-Agent: libcurl-agent/1.0

Content-type: application/json

Accept: application/json

Content-Length: 526   
   {
   "timestamp": 1571997083,
   "data": {
      "temperature": 20.613545532227,
      "humidity": 61.3828125,
      "battery": 3.47
   },
   "frame": "814962xxxx16a1dc5",
   "gatewayID": "AA555Axxxx0xx964",
   "othersGW": [],
   "clientID": "xxxx",
   "DevAddr": "011xxxxb",
   "DevEUI": "8cf9xxx000000xxx",
   "sensorInstallId": "8cf95xxx0000xxxx",
   "loraPort": 8,
   "fcnt": 1607,
   "rxpk": {
      "tmst": 2380181019,
      "time": "2019-10-25T09:51:23.472998Z",
      "chan": 0,
      "rfch": 0,
      "freq": 867.1,
      "stat": 1,
      "modu": "LORA",
      "datr": "SF7BW125",
      "codr": "4/5",
      "lsnr": 9,
      "rssi": -72,
      "size": 22,
      "data": "xxxxxxxxxxxxxxxx/YxWg=="
   }
}

so I would like to have data of temperature etc... and I don't know the node I have to use

Thanks a lot

回答1:

Having got a better view of what you are trying to do from the comments.

Using the TCP-in node is probably not the right approach for this. You will do much better using the HTTP-in/HTTP-out nodes as these will handle dealing with all the HTTP-header and sending a proper response to the client so the connection gets closed.

The HTTP-in node takes a path e.g. /input which will be appended to the Node-RED URL giving something like http://localhost:1880/input. It also takes a HTTP verb which in this case would be POST. You can find more details and lots of examples in the Node-RED cookbook here.

You will need to update the client to point to the correct path and port.

回答2:

You will need JSON node to convert the message string into an object.

Nodered has a very good documentation and hands on examples. See below for some help:

This is great example how to to use the json node
This describes how to work with JSON data

来源：https://stackoverflow.com/questions/58558447/extract-json-with-nodered

标签

json

node-red