Added: Adapter and CA4 model support

[ileodo]

Description

CA4 model uses miotspec protocol, the schema can be found http://miot-spec.org/miot-spec-v2/instance?type=urn:miot-spec-v2:device:humidifier:0000A00E:zhimi-ca4:2

miotspec communication can't fit in the current code structure easily, so as part of this PR, I introduced two components which can be potentially a alternative code structure.

The idea is have a base Humidifier class devices/MiHumidifierAdapter.js which encapsulate the common Services and Characteristics, then have different models' implementation inherited from it (devices/MiHumidifierCA4.js for CA4).

Inside the implementation code page, the characteristics are defined in a data driven fashion. here is an example.

{
   // id of the characteristic
   id     : 'CurrentHumidifierDehumidifierState',
   // owner service
   service: this.humidifierService,
   // characteristic's name
   type   : Characteristic.CurrentHumidifierDehumidifierState,
   // props of the characteristic, can be null
   props  : { validValues: [0, 2] },
   // define the action of getting characteristic
   get    : {
     // call name of the device call
     call_name        : 'get_properties',
     // a functor generate the payload in the device call
     call_args        : function (_this) {
       return [{ did: _this.device.id, siid: 2, piid: 1, value: null }]
     },
     // a functor to postprocess the response from the device
     response_callback: function (_this, result, callback) {
       callback(null, result[0].value
         ? Characteristic.CurrentHumidifierDehumidifierState.HUMIDIFYING
         : Characteristic.CurrentHumidifierDehumidifierState.INACTIVE)
     },
   },
 },

devices/MiHumidifierAdapter.js has a generic function registerCharacteristic to process the above data driven config.

devices/MiHumidifierFactory.js provided a factory function to instantiate the MiHumidifier based on the model in the config. If the model is not supported by the Factory, a null will be returned. Hence, there is no regression issue for all existing models.

Test

All characteristics have been tested with my CA4 device.

Note

Javascript is not my specialty language, please point me out if there is any js specific mistake I made.

Related issues:

#26

[ileodo]

#16

[ileodo]

newly supported model

[ileodo]

MiHumidifierFactory will return null if the config.model is not supported by the Adapters. so there is no impact on the existing supported models.

[nt0xa]

Hey @ileodo, thanks for the contribution! Looks good to me