Howto: Read a #VSCP mdf file with node.js

The Module Description file is a XML file that all VSCP devices must have and which describe the device. It can either be stored on the device itself or more common linked by the device and stored on some external server storage. Software that wants to configure a device can fetch this file to get the knowledge to do so. Typically a user interface use this file to guide a user through device configuration. A good thing is that one software can handle and configure any device.

A sample MDF file is here an here.

Read a mdf file from a device, parse it and display the module name. A device can consist of several modules, there will always be one and result.vscp.module[0] will always refer to the first. Most devices contains only one module. You can get the number of modules with result.vscp.module.length

Below are some Javascript examples on how to get information from the MDF-file.

Display the module name

const axios = require('axios');
const xml2js = require('xml2js');

let parser = new xml2js.Parser();

axios.get('https://www.eurosource.se/ntc10KA_3.xml')  
  .then((response) => {
      parser.parseString(response.data,
                         (err, result) => {
        console.dir(result.vscp.module[0].name);    
      });
  })  
  .catch((err) => {    
    console.log(err);  
  });

Similar to above sample get a link to the manual for a device

console.log(result.vscp.module[0].manual[0].$.path);

List all registers with

console.dir(result.vscp.module[0].registers[0].reg);

Iterate through all registers an display there names

axios.get('https://www.eurosource.se/ntc10KA_3.xml')
  .then((response) => {
    parser.parseString(response.data, (err, result) => {
      for (let reg of result.vscp.module[0].registers[0].reg) {
        console.log(reg.name[0]._);
      }
    });

  })
  .catch((err) => {
    console.log(err);
  });

List register descriptions with

console.log(reg.description[0]._);

You get the language code for a register name or a register description with

console.log(reg.name[0].$.lang);

List abstractions with

axios.get('https://www.eurosource.se/ntc10KA_3.xml')
  .then((response) => {
    parser.parseString(response.data, (err, result) => {
      for (let reg of result.vscp.module[0].registers[0].reg) {
        console.dir(result.vscp.module[0].abstractions[0].abstraction);
      }
    });

  })
  .catch((err) => {
    console.log(err);
  });



List number of events the module can generate and the events

console.dir('# events: ' + result.vscp.module[0].events[0].event.length);
console.dir(result.vscp.module[0].events[0].event);

If you want an url to a picture of the module

console.log(result.vscp.module[0].picture[0].$.path);

If you want the manual

console.log(result.vscp.module[0].manual[0].$.path);

or a firmware image

console.log(result.vscp.module[0].firmware[0].$.path);

The number of firmware images available

axios.get('http://www.eurosource.se/paris_010.xml')
  .then((response) => {
    parser.parseString(response.data, (err, result) => {
  console.log(result.vscp.module[0].firmware.length);
    });
  })
  .catch((err) => {
    console.log(err);
  });

The release date for a specific firmware

console.log(result.vscp.module[0].firmware[3].$.date);

The way this works should be obvious by now. Enjoy!

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