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Drupal example source code file (updater.inc)

This example Drupal source code file (updater.inc) is included in the DevDaily.com "Drupal Source Code Warehouse" project. The intent of this project is to help you "Learn Drupal by Example".

PHP - Drupal tags/keywords

array, directory, file, filetransfer, function, if, info_file, new, php, public, reason, return, source, throw

The updater.inc Drupal example source code

<?php
// $Id: updater.inc,v 1.8 2011/01/02 23:28:16 webchick Exp $

/**
 * @file
 * Classes used for updating various files in the Drupal webroot. These
 * classes use a FileTransfer object to actually perform the operations.
 * Normally, the FileTransfer is provided when the site owner is redirected to
 * authorize.php as part of a multistep process.
 */

/**
 * Interface for a class which can update a Drupal project.
 *
 * An Updater currently serves the following purposes:
 *   - It can take a given directory, and determine if it can operate on it.
 *   - It can move the contents of that directory into the appropriate place
 *     on the system using FileTransfer classes.
 *   - It can return a list of "next steps" after an update or install.
 *   - In the future, it will most likely perform some of those steps as well.
 */
interface DrupalUpdaterInterface {

  /**
   * Checks if the project is installed.
   *
   * @return bool
   */
  public function isInstalled();

  /**
   * Returns the system name of the project.
   *
   * @param string $directory
   *  A directory containing a project.
   */
  public static function getProjectName($directory);

  /**
   * @return string
   *   An absolute path to the default install location.
   */
  public function getInstallDirectory();

  /**
   * Determine if the Updater can handle the project provided in $directory.
   *
   * @todo: Provide something more rational here, like a project spec file.
   *
   * @param string $directory
   *
   * @return bool
   *   TRUE if the project is installed, FALSE if not.
   */
  public static function canUpdateDirectory($directory);

  /**
   * Actions to run after an install has occurred.
   */
  public function postInstall();

  /**
   * Actions to run after an update has occurred.
   */
  public function postUpdate();
}

/**
 * Base class for Updaters used in Drupal.
 */
class Updater {

  /**
   * @var string $source Directory to install from.
   */
  public $source;

  public function __construct($source) {
    $this->source = $source;
    $this->name = self::getProjectName($source);
    $this->title = self::getProjectTitle($source);
  }

  /**
   * Return an Updater of the appropriate type depending on the source.
   *
   * If a directory is provided which contains a module, will return a
   * ModuleUpdater.
   *
   * @param string $source
   *   Directory of a Drupal project.
   *
   * @return Updater
   */
  public static function factory($source) {
    if (is_dir($source)) {
      $updater = self::getUpdaterFromDirectory($source);
    }
    else {
      throw new UpdaterException(t('Unable to determine the type of the source directory.'));
    }
    return new $updater($source);
  }

  /**
   * Determine which Updater class can operate on the given directory.
   *
   * @param string $directory
   *   Extracted Drupal project.
   *
   * @return string
   *   The class name which can work with this project type.
   */
  public static function getUpdaterFromDirectory($directory) {
    // Gets a list of possible implementing classes.
    $updaters = drupal_get_updaters();
    foreach ($updaters as $updater) {
      $class = $updater['class'];
      if (call_user_func(array($class, 'canUpdateDirectory'), $directory)) {
        return $class;
      }
    }
    throw new UpdaterException(t('Cannot determine the type of project.'));
  }

  /**
   * Figure out what the most important (or only) info file is in a directory.
   *
   * Since there is no enforcement of which info file is the project's "main"
   * info file, this will get one with the same name as the directory, or the
   * first one it finds.  Not ideal, but needs a larger solution.
   *
   * @param string $directory
   *   Directory to search in.
   *
   * @return string
   *   Path to the info file.
   */
  public static function findInfoFile($directory) {
    $info_files = file_scan_directory($directory, '/.*\.info$/');
    if (!$info_files) {
      return FALSE;
    }
    foreach ($info_files as $info_file) {
      if (drupal_substr($info_file->filename, 0, -5) == basename($directory)) {
        // Info file Has the same name as the directory, return it.
        return $info_file->uri;
      }
    }
    // Otherwise, return the first one.
    $info_file = array_shift($info_files);
    return $info_file->uri;
  }

  /**
   * Get the name of the project directory (basename).
   *
   * @todo: It would be nice, if projects contained an info file which could
   *        provide their canonical name.
   *
   * @param string $directory
   *
   * @return string
   *   The name of the project.
   */
  public static function getProjectName($directory) {
    return basename($directory);
  }

  /**
   * Return the project name from a Drupal info file.
   *
   * @param string $directory
   *   Directory to search for the info file.
   *
   * @return string
   *   The title of the project.
   */
  public static function getProjectTitle($directory) {
    $info_file = self::findInfoFile($directory);
    $info = drupal_parse_info_file($info_file);
    if (empty($info)) {
      throw new UpdaterException(t('Unable to parse info file: %info_file.', array('%info_file' => $info_file)));
    }
    if (empty($info['name'])) {
      throw new UpdaterException(t("The info file (%info_file) does not define a 'name' attribute.", array('%info_file' => $info_file)));
    }
    return $info['name'];
  }

  /**
   * Store the default parameters for the Updater.
   *
   * @param array $overrides
   *   An array of overrides for the default parameters.
   *
   * @return array
   *   An array of configuration parameters for an update or install operation.
   */
  protected function getInstallArgs($overrides = array()) {
    $args = array(
      'make_backup' => FALSE,
      'install_dir' => $this->getInstallDirectory(),
      'backup_dir'  => $this->getBackupDir(),
    );
    return array_merge($args, $overrides);
  }

  /**
   * Updates a Drupal project, returns a list of next actions.
   *
   * @param FileTransfer $filetransfer
   *   Object that is a child of FileTransfer. Used for moving files
   *   to the server.
   * @param array $overrides
   *   An array of settings to override defaults; see self::getInstallArgs().
   *
   * @return array
   *   An array of links which the user may need to complete the update
   */
  public function update(&$filetransfer, $overrides = array()) {
    try {
      // Establish arguments with possible overrides.
      $args = $this->getInstallArgs($overrides);

      // Take a Backup.
      if ($args['make_backup']) {
        $this->makeBackup($args['install_dir'], $args['backup_dir']);
      }

      if (!$this->name) {
        // This is bad, don't want to delete the install directory.
        throw new UpdaterException(t('Fatal error in update, cowardly refusing to wipe out the install directory.'));
      }

      // Make sure the installation parent directory exists and is writable.
      $this->prepareInstallDirectory($filetransfer, $args['install_dir']);

      // Note: If the project is installed in sites/all, it will not be
      // deleted. It will be installed in sites/default as that will override
      // the sites/all reference and not break other sites which are using it.
      if (is_dir($args['install_dir'] . '/' . $this->name)) {
        // Remove the existing installed file.
        $filetransfer->removeDirectory($args['install_dir'] . '/' . $this->name);
      }

      // Copy the directory in place.
      $filetransfer->copyDirectory($this->source, $args['install_dir']);

      // Make sure what we just installed is readable by the web server.
      $this->makeWorldReadable($filetransfer, $args['install_dir'] . '/' . $this->name);

      // Run the updates.
      // @TODO: decide if we want to implement this.
      $this->postUpdate();

      // For now, just return a list of links of things to do.
      return $this->postUpdateTasks();
    }
    catch (FileTransferException $e) {
      throw new UpdaterFileTransferException(t('File Transfer failed, reason: !reason', array('!reason' => strtr($e->getMessage(), $e->arguments))));
    }
  }

  /**
   * Installs a Drupal project, returns a list of next actions.
   *
   * @param FileTransfer $filetransfer
   *   Object that is a child of FileTransfer.
   * @param array $overrides
   *   An array of settings to override defaults; see self::getInstallArgs().
   *
   * @return array
   *   An array of links which the user may need to complete the install.
   */
  public function install(&$filetransfer, $overrides = array()) {
    try {
      // Establish arguments with possible overrides.
      $args = $this->getInstallArgs($overrides);

      // Make sure the installation parent directory exists and is writable.
      $this->prepareInstallDirectory($filetransfer, $args['install_dir']);

      // Copy the directory in place.
      $filetransfer->copyDirectory($this->source, $args['install_dir']);

      // Make sure what we just installed is readable by the web server.
      $this->makeWorldReadable($filetransfer, $args['install_dir'] . '/' . $this->name);

      // Potentially enable something?
      // @TODO: decide if we want to implement this.
      $this->postInstall();
      // For now, just return a list of links of things to do.
      return $this->postInstallTasks();
    }
    catch (FileTransferException $e) {
      throw new UpdaterFileTransferException(t('File Transfer failed, reason: !reason', array('!reason' => strtr($e->getMessage(), $e->arguments))));
    }
  }

  /**
   * Make sure the installation parent directory exists and is writable.
   *
   * @param FileTransfer $filetransfer
   *   Object which is a child of FileTransfer.
   * @param string $directory
   *   The installation directory to prepare.
   */
  public function prepareInstallDirectory(&$filetransfer, $directory) {
    // Make the parent dir writable if need be and create the dir.
    if (!is_dir($directory)) {
      $parent_dir = dirname($directory);
      if (!is_writable($parent_dir)) {
        @chmod($parent_dir, 0755);
        // It is expected that this will fail if the directory is owned by the
        // FTP user. If the FTP user == web server, it will succeed.
        try {
          $filetransfer->createDirectory($directory);
          $this->makeWorldReadable($filetransfer, $directory);
        }
        catch (FileTransferException $e) {
          // Probably still not writable. Try to chmod and do it again.
          // @todo: Make a new exception class so we can catch it differently.
          try {
            $old_perms = substr(sprintf('%o', fileperms($parent_dir)), -4);
            $filetransfer->chmod($parent_dir, 0755);
            $filetransfer->createDirectory($directory);
            $this->makeWorldReadable($filetransfer, $directory);
            // Put the permissions back.
            $filetransfer->chmod($parent_dir, intval($old_perms, 8));
          }
          catch (FileTransferException $e) {
            $message = t($e->getMessage(), $e->arguments);
            $throw_message = t('Unable to create %directory due to the following: %reason', array('%directory' => $install_location, '%reason' => $message));
            throw new UpdaterException($throw_message);
          }
        }
        // Put the parent directory back.
        @chmod($parent_dir, 0555);
      }
    }
  }

  /**
   * Ensure that a given directory is world readable.
   *
   * @param FileTransfer $filetransfer
   *   Object which is a child of FileTransfer.
   * @param string $path
   *   The file path to make world readable.
   * @param bool $recursive
   *   If the chmod should be applied recursively.
   */
  public function makeWorldReadable(&$filetransfer, $path, $recursive = TRUE) {
    if (!is_executable($path)) {
      // Set it to read + execute.
      $new_perms = substr(sprintf('%o', fileperms($path)), -4, -1) . "5";
      $filetransfer->chmod($path, intval($new_perms, 8), $recursive);
    }
  }

  /**
   * Perform a backup.
   *
   * @todo Not implemented.
   */
  public function makeBackup(&$filetransfer, $from, $to) {
  }

  /**
   * Return the full path to a directory where backups should be written.
   */
  public function getBackupDir() {
    return file_stream_wrapper_get_instance_by_scheme('temporary')->getDirectoryPath();
  }

  /**
   * Perform actions after new code is updated.
   */
  public function postUpdate() {
  }

  /**
   * Perform actions after installation.
   */
  public function postInstall() {
  }

  /**
   * Return an array of links to pages that should be visited post operation.
   *
   * @return array
   *   Links which provide actions to take after the install is finished.
   */
  public function postInstallTasks() {
    return array();
  }

  /**
   * Return an array of links to pages that should be visited post operation.
   *
   * @return array
   *   Links which provide actions to take after the update is finished.
   */
  public function postUpdateTasks() {
    return array();
  }
}

/**
 * Exception class for the Updater class hierarchy.
 *
 * This is identical to the base Exception class, we just give it a more
 * specific name so that call sites that want to tell the difference can
 * specifically catch these exceptions and treat them differently.
 */
class UpdaterException extends Exception {
}

/**
 * Child class of UpdaterException that indicates a FileTransfer exception.
 *
 * We have to catch FileTransfer exceptions and wrap those in t(), since
 * FileTransfer is so low-level that it doesn't use any Drupal APIs and none
 * of the strings are translated.
 */
class UpdaterFileTransferException extends UpdaterException {
}

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