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Domoticzmochad bridgeassistant for dim/bright packets

A Python3 script to handle X10 bright/dim packets for dimmable devices in Domoticz

Version 0.5 (2024-03-10)

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FR : Le billet intituléDes appareils sans fil X10 refusent de mourir contient plus d'information sur ce sujet.

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mochad is "a Linux TCP gateway daemon for the X10 CM15A RF (radio frequency) and PL (power line) controller and the CM19A RF controller"source. All X10 power line and wireless packets received by a controller are retransmitted through TCP socket connections bymochad. However, theDomoticzMochad CM15Pro/CM19A bridge with LAN interface decodes only the On and Off packets received frommochad. Dim and Bright packets result in a decode error:

Error: Mochad: Cannot decode 'Rx RF House: J Func: Bright'

This script contains a user-defined dictionary of X10 units numbers and corresponding Domoticiz idx numbers for dimmable devices. It also keeps track of the last used X10 unit number. When a Dim/Bright packet is received, it attempts to decrease/increase the level of the last used X10 unit. It does this by obtaining the current light level of the corresponding device using theDomoticz HTTP/JSON API and then sets the new modified light level using the same API.

Themochas add-on service has been used with a CM15A controller which handles RF packets only. Consequently, RF packets from the CM19A should work, but no test has been done with PL packets that could be sent bymochad if that controller is used. Assuming that the only difference between RF and PL packets generated bymochad is the two-letter source label,

02/01 18:57:11 Rx RF HouseUnit: J1 Func: On02/01 18:57:15 Rx PL HouseUnit: J3 Func: On

then, starting with version 0.4,mochas should also work with power line X10 packets sent bymochad if connected to a CM15A. Again, this has not been tested.

Starting with version 0.5mochas offers support for thesecurity provisions introduced in Domoticz 2023.1.

It remains the case that only IPv4 host addresses are used.

Testing was done on a first generation Raspberry Pi B circa 2011 running bothmochas andmochad. The operation system was Raspberry Pi OS Lite (32-bit) (2024-01-25) for armhf with a 6.1.0 Linux kernel.

By default,mochas assumes Domoticz security settings are set at the lowest possible level. No user name and password are provided when using the Domoticz API with plain text HTTP requests. For this to workDomoticz andmochas must be on the same subnet which, in turn, must be included in theTrusted Networks (no username/password) in theDomoticz Security settings.

With version 0.5,mochas no longer needs to be on a trusted network. In that case, HTTP or HTTPS requests sent to Domoticz must contain the name and password of aDomoticz user with admin rights. The credentials must be a "username:password" base64 encoded string specified as an option in themochas.json configuration file.

"CREDS64":"cG9uZG1pc3Q6c2VhYnJlYXpl"

Insecure HTTP requests (the default inmochas) with credentials will be ignored by Domoticz unless
  [] Allow Basic-Auth authentication over plain HTTP (API only)
is checked inAPI Protection of theDomoticz Security settings.

In no way should base64 encoding be viewed as secure. It iseasily verified that the above example corresponds to the string "pondmist:seabreaze". Consequently if that option is used with HTTP requests, it amounts to sending the credentials as plain text in an HTTP header.

Starting with version 0.5, secure HTTP requests are enabled with

"TLS":true

in themochas.json configuration file. Because the digital certificate supplied with Domoticz is self-signed, verification will fail unless the self-signed certificate is replaced with a certificate from a recognized authority or if CA verification is disabled inmochas with the

"VERIFY":false

option in themochas.json configuration file.

• mochas - the executable Python3 script that should be installed in/usr/local/bin/.
• mochas.json.template - a model JSON configuration file that should be modified and installed in/etc/mochas/ asmochas.json.
• mochad.service - the systemd service file that could be installed in/etc/systemd/system/.

Ifmochas is installed in a directory other than the one suggested,ExecStart inmochad.service must be modified accordingly.

Onlyroot, the owner ofmochas in/usr/local/bin, should have read, write, and execute permissions over the script:
# sudo chmod 700 mochas

The configuration file is JSON formatted. Here is the template which will have to be edited.

{"LOGLEVEL":"error","HOST":"192.168.168.168","PORT":1099,"HOUSE":"J","DELTA":15,"CREDS64":"","TLS":false,"VERIFY":true,"DOMOTICZ":"192.168.168.168:8080","DEVICES": {"6":66,"7":177,"8":288    }}

If installingmochad on a recent Linux distribution withsystemd, such as Raspberry Pi OS, thenhttps://github.com/sigmdel/mochad might be a good fork to try.