BLE Characteristic gives an error: Cannot read property '....' of undefined

[koktaildotcom]

I did a rewrite for the app com.mi.flora that can read out sensor information from the xiaomi mi flora devices. It all works fine except for the second (and all other) timeout to read sensor information again.

I've searched for hours through my code but it looks something in core. The second time i want the sensors to read (i've disconnected the BlePeripheral correctly the first time) i cannot call write to the characteristic.

{ Error: Cannot read property '00001a0000001000800000805f9b34fb' of undefined 
   at Object.JSON.parse (/opt/homey-client/system/helpers/jsonfns.js:1:1190) 
   at JSON.parse (<anonymous>) 
   at jsonToObject (/opt/homey-client/system/helpers/jsonfns.js:1:1083) 
   at function.e.data.map.e (/opt/homey-client/system/manager/ManagerApps/bootstrap/sdk/v2/lib/HomeyClient.js:1:1379) 
   at Array.map (<anonymous>) 
   at HomeyClient._onMessage (/opt/homey-client/system/manager/ManagerApps/bootstrap/sdk/v2/lib/HomeyClient.js:1:1372) 
   at emitTwo (events.js:126:13) 
   at process.emit (events.js:214:7) 
   at emit (internal/child_process.js:762:12) 
   at _combinedTickCallback (internal/process/next_tick.js:142:11) 
 message: 'Cannot read property \'00001a0000001000800000805f9b34fb\' of undefined' } 
update device Philodendron erubescens 
(node:30900) UnhandledPromiseRejectionWarning: Error: Error: TypeError: Cannot read property 'read' of undefined 
   at /lib/MiFloraDriver.js:335:39 
   at <anonymous> 
   at process._tickCallback (internal/process/next_tick.js:189:7)

[koktaildotcom]

Can this be related to: #7 ?

[WeeJeWel]

What ID is 00001a0000001000800000805f9b34fb. Characteristic, service, etc?

[koktaildotcom]

Thats the data write characteristic.

[koktaildotcom]

If you have a 'xiaomi mi flora' device you can try this branch: https://github.com/koktaildotcom/homey-mi-flora/tree/feature/v2-rewrite?files=1

It accur the second time the sensor is read.

[koktaildotcom]

I've tried the branch on rc3 with all devices removed. Thought there could be a difference. But the same error occur.

[koktaildotcom]

Still an issue on rc4

[koktaildotcom]

Still an issue with rc7

[koktaildotcom]

@WeeJeWel any idea when you can take a look at this issue?

[koktaildotcom]

Still an issue with 2.0.0

[koktaildotcom]

The issue is verified by multiple alpha users.

[WeeJeWel]

We will address this issue in a 2.x release. Sorry for the delay!

[gerrit1968]

We will address this issue in a 2.x release. Sorry for the delay!

@WeeJeWel any idea when the problem with the BLE will be solved?

[WeeJeWel]

This issue has been resolved in Homey v2.0.5. Thank you for reporting!

[koktaildotcom]

This is still an issue on Homey v2.0.5

[koktaildotcom]

Sorry, wrong issue.

[koktaildotcom]

This issue: #7 is still a problem

[koktaildotcom]

Now i encounter this issue on Homey v2.0.5 (after PTP and reboot twice)

The log "already in realtime mode" is a test log to don't break on the error but notify that the service is cached and already in realtime mode. Can this be the problem? I can imagine that if you store an service in cache the state is static. But the BLE service of the Mi Flora is changed because you need to set the device in a 'real time data' state to be able to read data from the device.

return service.write(REALTIME_CHARACTERISTIC_UUID, Buffer.from([0xA0, 0x1F]), false).then(() => {
                        return service;
                    }).catch((error) => {
                        console.log(' ----- already in realtime mode!');
                        console.log(error);
                        return service;
                    });

Gives an error:

 ----- already in realtime mode!
{ Error: Cannot read property '00001a0000001000800000805f9b34fb' of undefined
    at Object.JSON.parse (/opt/homey-client/system/helpers/jsonfns.js:1:1190)
    at JSON.parse (<anonymous>)
    at jsonToObject (/opt/homey-client/system/helpers/jsonfns.js:1:1083)
    at function.e.data.map.e (/opt/homey-client/system/manager/ManagerApps/bootstrap/sdk/v2/lib/HomeyClient.js:1:1379)
    at Array.map (<anonymous>)
    at HomeyClient._onMessage (/opt/homey-client/system/manager/ManagerApps/bootstrap/sdk/v2/lib/HomeyClient.js:1:1372)
    at emitTwo (events.js:126:13)
    at process.emit (events.js:214:7)
    at emit (internal/child_process.js:762:12)
    at _combinedTickCallback (internal/process/next_tick.js:142:11)
  message: 'Cannot read property \'00001a0000001000800000805f9b34fb\' of undefined' }

[koktaildotcom]

I've been searching for a sollution for hours yesterday, but i've always get this exact error. I've tried to change the strategy into the 'foreach characteristic`.

It looks like internally the service is saved but the service of the device is changed. The first iteration of the update sequence works 100% of the time. The seconds one fails 100% of the time.

Can you have a look at the core if you run the branch: https://github.com/koktaildotcom/homey-mi-flora/tree/feature/v2-rewrite?files=1?

[koktaildotcom]

return service.write(REALTIME_CHARACTERISTIC_UUID, Buffer.from([0xA0, 0x1F]), false).then(() => {
                        return service;
                    }).catch((error) => {
                        console.log(' ----- already in realtime mode!');
                        console.log(error);
                        return service;
                    });

At this point the service is a data service from the discovery. The realtime characteristic cannot be found on the object once it is stored internally so it looks to me.

[koktaildotcom]

Looks related to: #73

[WeeJeWel]

I cannot seem to reproduce the issue. Could you please point me to a branch of your repository where this does occur?

[koktaildotcom]

1. Checkout: https://github.com/koktaildotcom/homey-mi-flora/tree/feature/v2-rewrite?files=1 and run the code.
2. Add a new device (or use an existing)
3. Wait until the second iteration kicks in, this is the point the error occur.

In lib/MiFloraDriver.js you van change the update interval (search for interval)

[WeeJeWel]

Fixed in v2.1.2-rc.4