Reading TwinCAT routes from target system using ads-client Node.js library (https://github.com/jisotalo/ads-client)

read-target-ads-routes.js

/*
Copyright (c) 2021 Jussi Isotalo <[email protected]>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/


//Reads TwinCAT routes from target system using ads-client library
//NOTE: Install ads-client 1.11.0+ first with command "npm i ads-client"
//https://github.com/jisotalo/ads-client
const ads = require('ads-client')

const client = new ads.Client({
  targetAmsNetId: 'localhost',
  targetAdsPort: 851,
  allowHalfOpen: true
})

client.connect()
  .then(async res => {
    console.log(`Connected to the ${res.targetAmsNetId}`)

    //Creates a read request packet
    const createPacket = (entryNumber) => {
      const data = Buffer.alloc(12)
      let pos = 0

      //0..3 IndexGroup
      data.writeUInt32LE(803, pos)
      pos += 4

      //4..7 IndexOffset
      data.writeUInt32LE(entryNumber, pos)
      pos += 4

      //8..11 Read data length
      data.writeUInt32LE(2092, pos)
      pos += 4

      return data
    }


    //Parses the response
    const parseEntry = (data) => {
      let entry = {}, pos = 0

      //0..5 Target AMSNetId
      entry.amsNetId = client.byteArrayToAmsNetIdStr(data.slice(pos, pos + ads.ADS.AMS_NET_ID_LENGTH))
      pos += ads.ADS.AMS_NET_ID_LENGTH

      //Something here (like transport type etc.) 38 bytes
      entry._unknown = data.slice(pos, pos + 38)
      pos += 38

      //Target address (unknown number of bytes)
      entry.address = ''
      do {
        let nextByte = data.slice(pos, pos + 1)
        pos++

        if (nextByte[0] == 0) {
          break

        } else {
          entry.address += nextByte.toString('ascii')
        }
      }
      while (true)


      //Target name (unknown number of bytes)
      entry.name = ''
      do {
        let nextByte = data.slice(pos, pos + 1)
        pos++

        if (nextByte[0] == 0) {
          break

        } else {
          entry.name += nextByte.toString('ascii')
        }
      }
      while (true)

      return entry
    }



    //Getting all entries one by one
    let entries = [], entryNumber = 0

    do {
      try {
        const result = await client.sendAdsCommand(
          ads.ADS.ADS_COMMAND.Read,
          createPacket(entryNumber),
          10000
        )

        entries.push(parseEntry(result.ads.data))
        entryNumber++

      } catch (err) {
        if (err.adsError && err.adsErrorInfo && err.adsErrorInfo.adsErrorCode == 1814) {
          //"No more notification handles" -> all entries received (not really an error)
          console.log('Done!')
        } else {
          console.log('Error:', err)
        }

        //Time to quit
        break
      }
    } while (true)

    console.log(entries)

    return await client.disconnect()
  })
  .then(() => {
    console.log('Disconnected')
  })
  .catch(err => {
    console.log('Something failed:', err)
  })

Updated to work with version 1.11.1