1<?php
2class Fetcher {
3  /**
4   * Fetches the data identified by $data_id, wraps it into FetchedData object together with
5   * any auxiliary information (like HTTP response headers, number of redirect, fetched file information
6   * or something else) and returns this object.
7   *
8   * @param String $data_id unique identifier of the data to be fetched (URI, file path, primary key of the database record or something else)
9   *
10   * @return FetchedData object containing the fetched file contents and auxiliary information, if exists.
11   */
12  function get_data($data_id) {
13    die("Oops. Inoverridden 'get_data' method called in ".get_class($this));
14  }
15
16  /**
17   * @return String value of base URL to use for resolving relative links inside the document
18   */
19  function get_base_url() {
20    die("Oops. Inoverridden 'get_base_url' method called in ".get_class($this));
21  }
22
23  function error_message() {
24    die("Oops. Inoverridden 'error_message' method called in ".get_class($this));
25  }
26}
27?>