<?php
  
  /**
   * This is an authentication backend that uses a file to manage passwords.
   *
   * The backend file must conform to Apache's htdigest format
   *
   * @package Sabre
   * @subpackage DAV
   * @copyright Copyright (C) 2007-2013 Rooftop Solutions. All rights reserved.
   * @author Evert Pot (http://www.rooftopsolutions.nl/) 
   * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
   */
  class Sabre_DAV_Auth_Backend_PDO extends Sabre_DAV_Auth_Backend_AbstractDigest {
  
      /**
       * Reference to PDO connection
       *
       * @var PDO
       */
      protected $pdo;
  
      /**
       * PDO table name we'll be using
       *
       * @var string
       */
      protected $tableName;
  
  
      /**
       * Creates the backend object.
       *
       * If the filename argument is passed in, it will parse out the specified file fist.
       *
       * @param PDO $pdo
       * @param string $tableName The PDO table name to use
       */
      public function __construct(PDO $pdo, $tableName = 'users') {
  
          $this->pdo = $pdo;
          $this->tableName = $tableName;
  
      }
  
      /**
       * Returns the digest hash for a user.
       *
       * @param string $realm
       * @param string $username
       * @return string|null
       */
      public function getDigestHash($realm,$username) {
  
          $stmt = $this->pdo->prepare('SELECT username, digesta1 FROM '.$this->tableName.' WHERE username = ?');
          $stmt->execute(array($username));
          $result = $stmt->fetchAll();
  
          if (!count($result)) return;
  
          return $result[0]['digesta1'];
  
      }
  
  }