gpio-property.js

// -*- mode: js; js-indent-level:2;  -*-
// SPDX-License-Identifier: MPL-2.0

/**
 *
 * Copyright 2018-present Samsung Electronics France SAS, and other contributors
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.*
 */

const console = require('console');

// Disable logs here by editing to '!console.log'
const log = console.log || function () {};

const { Property, Value } = require('webthing');

const gpio = require('gpio');

class GpioOutProperty extends Property {
  constructor(thing, name, value, metadata, config) {
    super(thing, name, new Value(Boolean(value)), {
      '@type': 'OnOffProperty',
      title: (metadata && metadata.title) || `On/Off: ${name}`,
      type: 'boolean',
      description: (metadata && metadata.description) || `GPIO Actuator on pin=${config.pin}`,
    });
    const self = this;
    this.config = config;
    this.port = gpio.export(config.pin, {
      direction: 'out',
      ready: () => {
        log(`log: GPIO: ${self.getName()}: open:`);
        self.value.valueForwarder = (value) => {
          try {
            log(`log: GPIO: ${self.getName()}: \
writing: ${value}`);
            self.port.set(value);
          } catch (err) {
            console.error(`error: GPIO: 
${self.getName()}: Fail to write: ${err}`);
            return err;
          }
        };
      },
    });
  }

  close() {
    try {
      this.port && this.port.unexport(this.config.pin);
    } catch (err) {
      console.error(`error: GPIO: ${this.getName()}: Fail to close: ${err}`);
      return err;
    }
    log(`log: GPIO: ${this.getName()}: close:`);
  }
}

class GpioInProperty extends Property {
  constructor(thing, name, value, metadata, config) {
    super(thing, name, new Value(Boolean(value)), {
      '@type': 'BooleanProperty',
      title: (metadata && metadata.title) || `On/Off: ${name}`,
      type: 'boolean',
      readOnly: true,
      description: (metadata && metadata.description) || `GPIO Sensor on pin=${config.pin}`,
    });
    const self = this;
    this.config = config;
    const callback = () => {
      log(`log: GPIO: ${self.getName()}: open:`);
      self.port.on('change', (value) => {
        value = Boolean(value);
        log(`log: GPIO: ${self.getName()}: change: ${value}`);
        self.value.notifyOfExternalUpdate(value);
      });
    };
    this.port = gpio.export(config.pin, { direction: 'in', ready: callback });
  }

  close() {
    try {
      this.port && this.port.unexport(this.config.pin);
    } catch (err) {
      console.error(`error: GPIO: ${this.getName()} close:${err}`);
      return err;
    }
    log(`log: GPIO: ${this.getName()}: close:`);
  }
}

function GpioProperty(thing, name, value, metadata, config) {
  if (config.direction === 'out') {
    return new GpioOutProperty(thing, name, value, metadata, config);
  } else if (config.direction === 'in') {
    return new GpioInProperty(thing, name, value, metadata, config);
  }
  throw 'error: Invalid param';
}

module.exports = GpioProperty;