homebridge-xiaomi-roborock-vacuum/miio/lib/tokens.js

Xiaomi Vacuum Cleaner - 1st (Mi Robot), 2nd (Roborock S50 + S55), 3rd Generation (Roborock S6) and S5 Max - plugin for Homebridge.

"use strict";

const fs = require("fs");
const path = require("path");

const mkdirp = require("mkdirp");
const AppDirectory = require("appdirectory");
const dirs = new AppDirectory("miio");

const CHECK_TIME = 1000;
const MAX_STALE_TIME = 120000;

const debug = require("debug")("miio:tokens");

/**
 * Shared storage for tokens of devices. Keeps a simple JSON file synced
 * with tokens connected to device ids.
 */
class Tokens {
  constructor() {
    this._file = path.join(dirs.userData(), "tokens.json");
    this._data = {};
    this._lastSync = 0;
  }

  get(deviceId) {
    const now = Date.now();
    const diff = now - this._lastSync;

    if (diff > CHECK_TIME) {
      return this._loadAndGet(deviceId);
    }

    return Promise.resolve(this._get(deviceId));
  }

  _get(deviceId) {
    return this._data[deviceId];
  }

  _loadAndGet(deviceId) {
    return this._load()
      .then(() => this._get(deviceId))
      .catch(() => null);
  }

  _load() {
    if (this._loading) return this._loading;

    return (this._loading = new Promise((resolve, reject) => {
      debug("Loading token storage from", this._file);
      fs.stat(this._file, (err, stat) => {
        if (err) {
          delete this._loading;
          if (err.code === "ENOENT") {
            debug("Token storage does not exist");
            this._lastSync = Date.now();
            resolve(this._data);
          } else {
            reject(err);
          }

          return;
        }

        if (!stat.isFile()) {
          // tokens.json does not exist
          delete this._loading;
          reject(new Error("tokens.json exists but is not a file"));
        } else if (
          Date.now() - this._lastSync > MAX_STALE_TIME ||
          stat.mtime.getTime() > this._lastSync
        ) {
          debug("Loading tokens");
          fs.readFile(this._file, (err, result) => {
            this._data = JSON.parse(result.toString());
            this._lastSync = Date.now();
            delete this._loading;
            resolve(this._data);
          });
        } else {
          delete this._loading;
          this._lastSync = Date.now();
          resolve(this._data);
        }
      });
    }));
  }

  update(deviceId, token) {
    return this._load().then(() => {
      this._data[deviceId] = token;

      if (this._saving) {
        this._dirty = true;
        return this._saving;
      }

      return (this._saving = new Promise((resolve, reject) => {
        const save = () => {
          debug("About to save tokens");
          fs.writeFile(
            this._file,
            JSON.stringify(this._data, null, 2),
            (err) => {
              if (err) {
                reject(err);
              } else {
                if (this._dirty) {
                  debug("Redoing save due to multiple updates");
                  this._dirty = false;
                  save();
                } else {
                  delete this._saving;
                  resolve();
                }
              }
            }
          );
        };

        mkdirp(dirs.userData(), (err) => {
          if (err) {
            reject(err);
            return;
          }

          save();
        });
      }));
    });
  }
}

module.exports = new Tokens();