tuyapi: Device returning JSON error

This bug was already mentioned in the TuyApi/Cli repo, but it fits here better, since it seems to fail already within TuyApi itself, not just in cli.

How I run into this Testing TuyApi with the sample code, I let the library find the device using the UDP broadcast, and it finds it, and determines it’s version 3.3 (at least thats what TuyApi returns together with it’s IP address).

Issue at TuyApi/Cli: https://github.com/TuyaAPI/cli/issues/23#issuecomment-525759663

My latest findings in the linked issue (copy from the other issue, to keep it clean):

@codetheweb (2 edits and more testing at the end of this feedback)

This is the response of a custom script against TuyAPI:

  TuyAPI Finding missing IP undefined or ID XXXXXXXXXXXXXXXXX +0ms
  TuyAPI Received UDP message. +77ms
  TuyAPI UDP data: +3ms
  TuyAPI { payload:
  TuyAPI    { ip: '192.168.1.XXX',
  TuyAPI      gwId: 'XXXXXXXXXXXXXXXXX',
  TuyAPI      active: 2,
  TuyAPI      ablilty: 0,
  TuyAPI      encrypt: true,
  TuyAPI      productKey: 'XXXXXXXXXXXXXXXXX',
  TuyAPI      version: '3.3' },
  TuyAPI   leftover: false,
  TuyAPI   commandByte: 19,
  TuyAPI   sequenceN: 0 } +0ms
  TuyAPI Connecting to 192.168.1.XXX... +4ms
  TuyAPI Socket connected. +73ms
Connected to device!
  TuyAPI GET Payload: +1ms
  TuyAPI { gwId: 'XXXXXXXXXXXXXXXXX',
  TuyAPI   devId: 'XXXXXXXXXXXXXXXXX' } +0ms
  TuyAPI Received data: 000055aa000000010000000a0000002c00000001e43a9f9fb09424634104f66db124feee8e3bf2aeee7be51f9590b6b57c1fe62e4f61356e0000aa55 +86ms
  TuyAPI Parsed: +0ms
  TuyAPI { payload: 'json obj data unvalid',
  TuyAPI   leftover: false,
  TuyAPI   commandByte: 10,
  TuyAPI   sequenceN: 1 } +0ms
Data from device: json obj data unvalid

Using this almost unchanged sample code:

const TuyAPI = require('tuyapi');

const device = new TuyAPI({
  id: 'XXXXXXXXXXXXXXXXX',
  key: 'XXXXXXXXXXXXXXXXX'});

let stateHasChanged = false;

// Find device on network
device.find().then(() => {
  // Connect to device
  device.connect();
});

// Add event listeners
device.on('connected', () => {
  console.log('Connected to device!');
});

device.on('disconnected', () => {
  console.log('Disconnected from device.');
});

device.on('error', error => {
  console.log('Error!', error);
});

device.on('data', data => {
  console.log('Data from device:', data);

  console.log(`Boolean status of default property: ${data.dps['1']}.`);

  // Set default property to opposite
  if (!stateHasChanged) {
    device.set({set: !(data.dps['1'])});

    // Otherwise we'll be stuck in an endless
    // loop of toggling the state.
    stateHasChanged = true;
  }
});

// Disconnect after 10 seconds
setTimeout(() => { device.disconnect(); }, 10000);

Command:

DEBUG=* node index.js

// EDIT 1/2 //

In file node_modules/tuyapi/lib/message-parser.js I followed it to getPayload (line 173) and did some console.log’s, in the first try statement I can log the buffer, then after that it does:

data = this.cipher.decrypt(data);

Followed by another console.log which gives me the following (partially cutted unrelated feedback):

  TuyAPI Received data: 000055aa000000010000000a0000002c00000001e43a9f9fb09424634104f66db124feee8e3bf2aeee7be51f9590b6b57c1fe62e4f61356e0000aa55 +13ms
========== BEFORE this.cipher.decrypt ==========
<Buffer e4 3a 9f 9f b0 94 24 63 41 04 f6 6d b1 24 fe ee 8e 3b f2 ae ee 7b e5 1f 95 90 b6 b5 7c 1f e6 2e>
========== AFTER this.cipher.decrypt ==========
json obj data unvalid

No idea how to move further, also no idea if the json obj data unvalid text is really the decrypted text, or an error from cipher (given the spelling error in unvalid).

// EDIT 2/2 //

Tested more in cipher, the weird error is already generated here:

node_modules/tuyapi/lib/cipher.js (line 75)

      const decipher = crypto.createDecipheriv('aes-128-ecb', this.key, '');
      result = decipher.update(data, format, 'utf8');
      result += decipher.final('utf8');

It’s the literal content of result after this part. Tested a bit more on the cipher stuff:

      const decipher = crypto.createDecipheriv('aes-128-ecb', this.key, '');
      result = decipher.update(data, format, 'utf8');
      console.log( 'RESULT 1' );
      console.log( result );
      result += decipher.final('utf8');
      console.log( 'RESULT 2' );
      console.log( result );

Results in:

RESULT 1
json obj data un
RESULT 2
json obj data unvalid

At this point it goes to crypto, and now i’m clueless what I could test more. Looks like the decryption works perfectly, since it fails when I change alghoritm, so the error is the decoded message. Do I guess the JSON payload is not correct or something, for my device:

const payload = {
      gwId: this.device.gwID,
      devId: this.device.id
    };