Highcharts: reading data from a dictionary stored in a text file-CodePudding

I'm trying to figure out how to get sensor data from a python script output into Highcharts. Rather than write all my code directly in javascript, I decided to save the python sensor data as a dictionary in a text file. My data.txt file looks like this:

    {'outdoor_temp': 45.7, 'outdoor_humid': 91.8}

The relevant portion of my Highcharts code looks like this:

    load: function () {
    var series = this.series[0];
    setInterval(function () {
      var x = (new Date()).getTime(), 
      file=fopen(data.txt,0)
      y = (file["outdoor_temp"]);
      series.addPoint([x, y], true, true);
    }, 2000);

Why doesn't this read the dictionary value stored in data.txt?

CodePudding user response：

If you want to store your data in files I would recommend you use JSON. JSON is supported out of the box by both Python and JavaScript and is very easy to work with.

Write file using Python

import json

data = {'outdoor_temp': 45.7, 'outdoor_humid': 91.8}

with open("data.json", "w") as f:
    json.dump(data, f)

The created data.json file then looks like this:

{"outdoor_temp": 45.7, "outdoor_humid": 91.8}

Read file using Node and JavaScript

You can then read the created file using the following Node program:

import { readFile } from "fs/promises";

// await can only be used in an async function 
(async () => {
  const file = await readFile("data.json", { encoding: "utf-8"});
  const parsed = JSON.parse(file);
  // log all data
  console.log(parsed);
  // log outdoor temperature
  console.log(parsed.outdoor_temp)
})()

Please note: You will need to implement some error handling for the above programs yourself.

Remarks

If you want to store the data and maybe do some calculations, do more visualizations etc. I recommend you use a database such as MongoDB or a timeseries database such as InfluxDB instead of single files. Grafana has integrations for them as well if you are looking for some nice visualization tool for your data.