islandora/includes/utilities.inc

<?php

/**
 * @file
 * Contains islandora utility functions
 */

/**
 * Convert bytes to human readable format
 *
 * XXX: Shouldn't Drupal's format_size() be preferred?
 *
 * @param integer bytes Size in bytes to convert
 * @return string
 */
function islandora_convert_bytes_to_human_readable($bytes, $precision = 2) {
  $kilobyte = 1024;
  $megabyte = $kilobyte * 1024;
  $gigabyte = $megabyte * 1024;
  $terabyte = $gigabyte * 1024;

  if (($bytes >= 0) && ($bytes < $kilobyte)) {
    return $bytes . ' B';
  }
  elseif (($bytes >= $kilobyte) && ($bytes < $megabyte)) {
    return round($bytes / $kilobyte, $precision) . ' KB';
  }
  elseif (($bytes >= $megabyte) && ($bytes < $gigabyte)) {
    return round($bytes / $megabyte, $precision) . ' MB';
  }
  elseif (($bytes >= $gigabyte) && ($bytes < $terabyte)) {
    return round($bytes / $gigabyte, $precision) . ' GB';
  }
  elseif ($bytes >= $terabyte) {
    return round($bytes / $terabyte, $precision) . ' TB';
  }
  else {
    return $bytes . ' B';
  }
}

/**
 * Creates a label for control group symbols.
 */
function islandora_control_group_to_human_readable($control_group) {
  switch ($control_group) {
    case 'M':
      return '<b>M</b>anaged';
    case 'X':
      return 'Inline <b>X</b>ML';
    case 'R':
      return '<b>R</b>edirect';
    case 'E':
      return '<b>E</b>xternally Referenced';
    default:
      return $control_group;
  }
}

/**
 * Checks if the given pid is valid.
 *
 * @param string $pid
 *   The object id to check.
 *
 * @return boolean
 *   TRUE if valid, FALSE otherwise.
 */
function islandora_is_valid_pid($pid) {
  return drupal_strlen(trim($pid)) <= 64 && preg_match('/^([A-Za-z0-9]|-|\.)+:(([A-Za-z0-9])|-|\.|~|_|(%[0-9A-F]{2}))+$/', trim($pid));
}

/**
 * Checks if the given datastream id is valid.
 *
 * @param string $dsid
 *   The datastream id to check.
 *
 * @return boolean
 *   TRUE if valid, FALSE otherwise.
 */
function islandora_is_valid_dsid($dsid) {
  return drupal_strlen(trim($dsid)) <= 64 && preg_match('/^[a-zA-Z0-9\_\-\.]+$/', trim($dsid));
}

/**
 * Helper function to describe a Fedora repository.
 *
 * Can be used to check if Fedora is available.
 *
 * @param string $url
 *   A url to a Fedora repository, if NULL the default is used.
 * @return
 *   Returns an array describing the repository. Returns FALSE if Fedora is down
 *   or if the url is incorrect.
 */
function islandora_describe_repository($url = NULL) {
  $url = isset($url) ? $url : variable_get('islandora_base_url', 'http://localhost:8080/fedora');
  $connection = new IslandoraTuque(NULL, $url);
  try {
    $info = $connection->api->a->describeRepository();
    return $info;
  }
  catch (RepositoryException $e) {
    return FALSE;
  }
}

/**
 * Build a list of all the hooks to call.
 *
 * Concatenates the each pid (escaped) to the hook name, for calling in
 * module_invoke_all().
 *
 * @param string $hook
 *   A hook to call.
 * @param array $pids
 *   An array of PIDs (probably content models).
 *
 * @return array
 *   An array with each PID escaped and concatenated with the base hook name,
 *   in addition to the base hook name at the end.
 */
function islandora_build_hook_list($hook, $pids = array()) {
  $hooks = array();

  foreach ($pids as $model) {
    $hooks[] = islandora_escape_pid_for_function($model) . '_' . $hook;
  }
  $hooks[] = $hook;

  return $hooks;
}

/**
 * Escape a Fedora PID to be valid inside of a PHP function name.
 *
 * Originally intended to allow inclusion of a PID in a module_invoke_all()
 * call.
 */
function islandora_escape_pid_for_function($pid) {
  // Apparently, case doesn't matter for function calls in PHP, so let's not
  //   really worry about changing the case.
  return str_replace(
    // Any PID characters which are not valid in the name of a PHP function.
    array(
      ':',
      '-',
    ),
    '_',
    $pid
  );
}

/**
 * Gets the namespace of the given id.
 *
 * @param string $id
 *   Either a PID or namespace to check for accessibility. Any string like those below are fine.
 * @code
 *  'islandora',
 *  'islandora:',
 *  'islandora:1234',
 * @endcode
 *
 * @return string
 *   The namespace portion of the given string.
 */
function islandora_get_namespace($id) {
  $matches = array();
  preg_match('/^([^:]*)/', $id, $matches);
  return $matches[0];
}

/**
 * Checks the given namespace or PID is/has an accessible namespace as defined by the "islandora_pids_allowed" variable.
 *
 * @param string $namespace
 *   Either a PID or namespace to check for accessibility. Any string like those below are fine.
 * @code
 *  'islandora',
 *  'islandora:',
 *  'islandora:1234',
 * @endcode
 *
 * @return boolean
 *   TRUE if accessible, FALSE otherwise.
 */
function islandora_namespace_accessible($id) {
  if (variable_get('islandora_namespace_restriction_enforced', FALSE)) {
    $namespace = islandora_get_namespace($id) . ':';
    $allowed_namespaces = explode(" ", variable_get('islandora_pids_allowed', 'default: demo: changeme: islandora: ilives: islandora-book: books: newspapers: '));
    return in_array($namespace, $allowed_namespaces);
  }
  return TRUE;
}