Class Index

vision/textDetection.js:34–129

* State manager for text processing. Stores and reads results from Redis.

 * State manager for text processing.  Stores and reads results from Redis.
 */
class Index {
  /**
   * Create a new Index object.
   */
  constructor() {
    // Connect to a redis server.
    const TOKEN_DB = 0;
    const DOCS_DB = 1;
    const PORT = process.env.REDIS_PORT || '6379';
    const HOST = process.env.REDIS_HOST || '127.0.0.1';

    this.tokenClient = redis
      .createClient({url: `redis://${HOST}:${PORT}`, db: TOKEN_DB})
      .on('error', err => {
        console.error('ERR:REDIS: ' + err);
        throw err;
      });
    this.docsClient = redis
      .createClient({url: `redis://${HOST}:${PORT}`, db: DOCS_DB})
      .on('error', err => {
        console.error('ERR:REDIS: ' + err);
        throw err;
      });

    (async () => {
      await this.tokenClient.connect();
      await this.docsClient.connect();
    })();
  }

  /**
   * Close all active redis server connections.
   */
  quit() {
    this.tokenClient.quit();
    this.docsClient.quit();
  }

  /**
   * Tokenize the given document.
   * @param {string} filename - key for the storage in redis
   * @param {string} document - Collection of words to be tokenized
   * @returns {Promise<void>}
   */
  async add(filename, document) {
    const PUNCTUATION = ['.', ',', ':', ''];
    const tokenizer = new natural.WordTokenizer();
    const tokens = tokenizer.tokenize(document);
    // filter out punctuation, then add all tokens to a redis set.
    await Promise.all(
      tokens
        .filter(token => PUNCTUATION.indexOf(token) === -1)
        .map(token => this.tokenClient.sAdd(token, filename))
    );
    await this.docsClient.set(filename, document);
  }

  /**