patriksimek/node-mssql

const fs = require('fs');
const os = require('os');
const mssql = require('mssql');

class Database {

  /**
   * Ottieni il riferimento alla libreria di riferimento
   *
   * @static
   * @returns
   *
   * @memberof Database
   */
  static getLib() {
    return mssql;
  }

  /**
   * Apri connessione al database usando le configurazioni impostate.
   *
   * @private
   * @static
   * @param {string} [username]
   * @param {string} [password]
   * @param {string} [server]
   * @param {string} [database]
   * @returns
   *
   * @memberof Database
   */
  static openConnection(username, password, server, database) {
    if (Object.prototype.hasOwnProperty.call(this, 'connectionPromise') === true && this.connectionPromise !== null) {
      return this.connectionPromise;
    }

    const configuration = this.getConfiguration(username, password, server, database);

    if (!this.enable) {
      return Promise.reject('Database disabled.');
    }


    this.connectionPool = new mssql.ConnectionPool(configuration);
    this.connectionPromise = this.connectionPool.connect();

    return this.connectionPromise;
  }

  static closeConnection() {
    this.connectionPool.close();
  }

  /**
   * Promessa alla connessione del database, che verrà avviata non appena viene richiesta la prima volta.
   *
   * @public
   * @static
   * @returns {Promise} <ConnectionPool>
   *
   * @memberof Database
   */
  static willConnect() {
    if (Object.prototype.hasOwnProperty.call(this, 'connectionPromise') === false || this.connectionPromise === null) {
      try {
        return this.openConnection();
      } catch (err) {
        console.error('willConnect: Database not connected.');
        throw new Error(err);
      }
    }

    return this.connectionPromise;
  }

  static getConnectionPool() {
    return this.connectionPool;
  }

  /**
   * Ottieni l'oggetto di configurazione per la connessione al database.
   *
   * @private
   * @static
   * @param {string} [username]
   * @param {string} [password]
   * @param {string} [server]
   * @param {string} [database]
   * @memberof Database
   */
  static getConfiguration(username, password, server, database) {
    let storedUsername = null;
    let storedPassword = null;
    let storedServer = null;
    let storedDatabase = null;
    let storedTimeout = null;

    try {
      fs.accessSync(`${__dirname}/../../config.js`);

      const config = require(`${__dirname}/../../config`);

      this.enable = config[this.configKey] ? config[this.configKey].enable : this.enable;
      storedUsername = config[this.configKey] ? config[this.configKey].username : null;
      storedPassword = config[this.configKey] ? config[this.configKey].password : null;
      storedServer = config[this.configKey] ? config[this.configKey].server : null;
      storedDatabase = config[this.configKey] ? config[this.configKey].database : null;
      storedTimeout = config[this.configKey] ? config[this.configKey].timeout : null;
    } catch (err) {
      console.warn(err);
    }

    return {
      user: storedUsername || username || '',
      password: storedPassword || password || '',
      server: storedServer || server || 'localhost',
      database: storedDatabase || database || '',
      connectionTimeout: storedTimeout || '15000',
      requestTimeout: storedTimeout || '15000',
      options: {
        appName: os.hostname(),
      },
    };
  }