node-red split values from webserver

1
votes

I am trying to node-red to poll the webserver in my Daikin heat pump to get inside and outside temeperatures so I can log them against the schedule I've also configured the unit with.

When polling it for the values, it returns this string of text

"ret=OK,htemp=21.5,hhum=-,otemp=18.0,err=0,cmpfreq=0"

I use this code in a node-red function to split them at the commas

msg.payload = msg.payload.split(",");
return msg;

It returns an array with 6 fields like this:

array[6]
0: "ret=OK"
1: "htemp=21.5"
2: "hhum=-"
3: "otemp=18.0"
4: "err=0"
5: "cmpfreq=0"

This is then put into influxdb by node-red with the numeric fields of the array being the fields created.

I'm unable to analyse this data because it has the text in the fields that end up in the influxdb. I can't work out how to remove the text to the left of and including the = sign without creating errors in node-red.

As a minimum, I'd like the data to be like this:

array[6]
0: "OK"
1: "21.5"
2: "-"
3: "18.0"
4: "0"
5: "0"

Even better would be to use the text to the left of the = sign as the field values in the array so they populate in influxdb. This would make analyics easier.

It would then look like this(extra spaces to line up colons for readability):

    array[6]
    ret: "OK"
  htemp: "21.5"
   hhum: "-"
  otemp: "18.0"
    err: "0"
cmpfreq: "0"

I know the syntax is javascript based, but I'm not strong enough in the area to figure this one out. I've been at it for a day and have had no luck.

Thanks!

P.S. for anyone who owns a Daikin US7 with Wifi and wants to control it over IP, I've been using this repo to get the values I need to send to the webserver.

Updates with requested info

InfluxDB is v0.10.0, webui says go1.6rc1 Node-RED is v.0.16.2 Node-RED is using node-red-contrib-influxdb v0.1.1

When I used this code in the function:

msg.payload = msg.payload.split(",").split("=")[0];
return msg;

I got this error when putting a debug tag on the output of the function:

function : (error)
"TypeError: msg.payload.split(...).split is not a function"

flow layout and error

2
javascriptnode-red
Update the question with what you've tried - hardillb
What version of InfluxDB? (I used old and new, and there are differences in how/what you can post to it) - Hugues M.
Along with the version, also please specify how you write to InfluxDB (manual POST to URL ? Using a contrib plugin for NodeRed ?...). The "line protocol" of InfluxDB expects pretty much a line as your original string (assuming you're ok with all numeric values being floats), so there might be no need to deconstruct/reconstruct it. - Hugues M.

2 Answers

0
votes

According to the doc, the output node expects an Object payload with the properties/values you want to push to InfluxDB.

So you need to split up that input string, and for that your first call to .split(',') is correct. But this returns an Array of Strings, which cannot be split again with .split('=') (hence the error you get).

Here is how you split the second level of key=value pairs and put those in an object:

var o = {}; // new empty Object that will be used for next payload
msg.payload.split(',').forEach(function(kv) { // loop on 'key=value' entries in array
    var pair = kv.split('='); // split entry to isolate key and value
    var key = pair[0];
    var value = pair[1];
    o[key] = value; // save that as new property for our Object
});
msg.payload = o; // Make that object the new payload

(edited with comments)

0
votes

For this you can just leverage the querystring module found in the node core.

const querystring = require('querystring');
const parsed = querystring.parse(msg.payload, ',');
// convert the numbers to numbers instead of strings
Object.keys(parsed).forEach(function (key) {
    const numberValue = +parsed[key];
    // if the value converted to number is Not A Number then don't change it 
    if (isNaN(numberValue)) return;
    parsed[key] = numberValue;
});
msg.payload = parsed;

The second argument to querystring.parse is the separator, check the docs for more info.