True public / private download option for filefield (Peer review request)

---------------------------- filefield_private.info -----------------------------

; $Id$
name = FileField Private Downloads
description = "Adds private file download options when using FileField."
core = 6.x
package = CCK
dependencies[] = filefield

-------------------------- filefield_private.module ----------------------------

<?php
// $Id$

/**
 * Implementation of hook_widget_settings_alter().
 */
function filefield_private_field_settings_alter(&$settings, $op, $widget) {
  // Only support modules that implement hook_filefield_private_file_widgets().
  $widget_type = isset($widget['widget_type']) ? $widget['widget_type'] : $widget['type'];
  if (!in_array($widget_type, array_keys(filefield_private_file_widgets()))) {
    return;
  }

  // Add our new options to the list of settings to be saved.
  if ($op == 'save') {
    $settings = array_merge($settings, array('filefield_private_downloads'));
  }

  // Add the additional settings to the form.
  if ($op == 'form') {
    $settings['filefield_private_downloads'] = array(
      '#type' => 'checkbox',
      '#title' => t('Private downloads'),
      '#default_value' => (bool) $widget['filefield_private_downloads'],
      '#description' => t('Enables private downloads.'),
    );
  }
}

function filefield_private_file_widgets($reset = FALSE) {
  static $widgets;
  if (!isset($widgets) || $reset) {
    $widgets = module_invoke_all('filefield_private_file_widgets');
  }
  return $widgets;
}

/**
 * Implementation of hook_filefield_private_file_widgets().
 */
function filefield_private_filefield_private_file_widgets() {
  return array(
    'filefield_widget', 'imagefield_widget',
  );
}


function filefield_private_file_fields($reset = FALSE) {
  static $widgets;
  if (!isset($widgets) || $reset) {
    $widgets = module_invoke_all('filefield_private_file_fields');
  }
  return $widgets;
}

/**
 * Implementation of hook_filefield_private_file_fields().
 */
function filefield_private_filefield_private_file_fields() {
  return array(
    'filefield',
  );
}

/**
* Implementation of hook_theme().
*/
function filefield_private_theme($existing, $type, $theme, $path) {
  return array(
    'filefield_private_file' => array('arguments' => array('element' => NULL))
  );
}

/**
 * Theme function for overriden field formatter theme callback.
 */
function theme_filefield_private_file($element) {
  global $conf;
  $system_directory_path = $conf['file_directory_path'];
  $system_file_downloads = $conf['file_downloads'];
  $filefield_private_directory_path = variable_get('filefield_private_directory_path', $system_directory_path);
  $filefield_private_file_downloads = FILE_DOWNLOADS_PRIVATE;

  $conf['file_directory_path'] = $filefield_private_directory_path;
  $conf['file_downloads'] = $filefield_private_file_downloads;

  if (isset($element['#old-theme']) && isset($element['#old-formatter'])) {
    $element['#theme'] = $element['#old-theme'];
    $element['#formatter'] = $element['#old-formatter'];
  }
  // Stop recursion
  if ($element['#formatter'] == 'private_file_download') {
    $element['#formatter'] = 'default';
    $element['#theme'] = 'filefield_formatter_default';
  }
  $output = theme($element['#theme'], $element);
  if (preg_match_all('/(href|src)="([^"]*)'. preg_quote(basename($element['#item']['filepath'])) .'"/', $output, $matches)) {
    foreach ($matches[0] as $index => $link) {
      $private_link = $matches[1][$index] .'="'. url('filefield-private/files/'.
          $element['#node']->nid .'/'.
          $element['#field_name'] .'/'.
          $element['#item']['fid'], array('absolute' => TRUE)) .'"';
      $output = str_replace($matches[0][$index], $private_link, $output);
    }
  }
  else {
    // No match, possible error
    $output = '';
  }
  $conf['file_directory_path'] = $system_directory_path;
  $conf['file_downloads'] = $system_file_downloads;

  return $output;
}


/**
* Implementation of hook_menu().
*/
function filefield_private_menu() {
  $items = array();
  $items['filefield-private/files/%node/%/%'] = array(
    'title' => 'File download',
    'page callback' => 'filefield_private_download',
    'page arguments' => array(2, 3, 4),
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
  );
  return $items;
}

function filefield_private_form_alter(&$form, $from_state, $form_id) {
  switch ($form_id) {
    case 'system_file_system_settings':
      $form['filefield_private_directory_path'] = array(
        '#type' => 'textfield',
        '#title' => t('Custom directory for user application files'),
        '#default_value' => variable_get('filefield_private_directory_path', file_directory_path()),
        '#maxlength' => 255,
        '#description' => t('A file system path where the files will be stored if the %type option above is selected. This directory must exist and be writable by Drupal. The download method will be treated as private.',
            array('%type' => t('Private downloads for user application files?'))),
        '#after_build' => array('system_check_directory'),
      );
  }
}

/**
 * Implements hook_nodeapi().
 */
function filefield_private_nodeapi(&$node, $op, $a3 = NULL, $a4 = NULL) {
  if ($op == 'view') {
    $content_type = content_types($node->type);
    $file_fields = filefield_private_file_fields();
    foreach ($content_type['fields'] as $field) {
      if (!empty($field['filefield_private_downloads']) && in_array($field['type'], $file_fields) && isset($node->content[$field['field_name']])
        && is_array($node->content[$field['field_name']])) {
        $instance = $node->content[$field['field_name']];
        foreach ($node->content[$field['field_name']]['field']['items'] as $delta => $item) {
          $item['#old-theme'] = $item['#theme'];
          $item['#old-formatter'] = $item['#formatter'];
          $item['#theme'] = 'filefield_private_file';
          $item['#formatter'] = NULL;
          $node->content[$field['field_name']]['field']['items'][$delta] = $item;
        }
      }
    }
  }
  elseif ($op == 'insert' || $op == 'update') {
    filefield_private_move_files($node);
  }
}

function filefield_private_move_files(&$node) {
  global $conf;
  if (is_object($node)) {
    $files = array();

    $system_directory_path = $conf['file_directory_path'];
    $real_system_directory_path = realpath($system_directory_path);

    $filefield_private_directory_path = variable_get('filefield_private_directory_path', $system_directory_path);
    $real_filefield_private_directory_path = realpath($filefield_private_directory_path);

    $content_type = content_types($node->type);
    $file_fields = filefield_private_file_fields();

    foreach ($content_type['fields'] as $field) {
      if (!empty($field['filefield_private_downloads']) && in_array($field['type'], $file_fields) && isset($node->$field['field_name']) && is_array($node->$field['field_name'])) {
        foreach ($node->$field['field_name'] as $file) {
          if (file_exists($file['filepath'])) {
            $file['realpath'] = realpath($file['filepath']);
            // If within the application path, ignore the file
            if (strpos($file['realpath'], $real_filefield_private_directory_path) !== 0) {
              $file['relative_path'] = ltrim(substr($file['realpath'], strlen($real_system_directory_path)), '\\/');
              $file['dest'] = rtrim($filefield_private_directory_path, '\\/') . DIRECTORY_SEPARATOR . $file['relative_path'];
              $files [$file['fid']] = $file;
            }
          }
        }
      }
    }
    $conf['file_directory_path'] = $filefield_private_directory_path;
    foreach ($files as $file) {
      $src = $file['filepath'];
      if (file_move($src, dirname($file['dest']), FILE_EXISTS_RENAME)) {
        // update db
        db_query("UPDATE {files} SET filepath = '%s' WHERE filepath = '%s'", $src, $file['filepath']);
      }
    }
    $conf['file_directory_path'] = $system_directory_path;
  }
}

/**
 * Call modules that implement hook_file_download() to find out if a file is
 * accessible and what headers it should be transferred with. If a module
 * returns -1 drupal_access_denied() will be returned. If one or more modules
 * returned headers the download will start with the returned headers. If no
 * modules respond drupal_not_found() will be returned.
 */
function filefield_private_download($node, $field_name, $fid) {
  global $conf;
  if (!node_access('view', $node)) {
    return drupal_access_denied();
  }
  $filepath = '';
  if (!empty($node->$field_name)) {
    foreach ($node->$field_name as $file) {
      if (file_exists($file['filepath'])) {
        $filepath = $file['filepath'];
        break;
      }
    }
  }
  if (file_exists($filepath)) {
    $headers = module_invoke_all('file_download', $filepath);
    $headers = array_merge($headers, module_invoke_all('file_private_download', $filepath));
    if (in_array(-1, $headers)) {
      return drupal_access_denied();
    }
    if (count($headers)) {
      $filefield_private_directory_path = variable_get('filefield_private_directory_path', $system_directory_path);
      $system_directory_path = $conf['file_directory_path'];
      $conf['file_directory_path'] = $filefield_private_directory_path;
      file_transfer($filepath, $headers);
      $conf['file_directory_path'] = $system_directory_path;
    }
  }
  return drupal_not_found();
}

function filefield_private_file_private_download ($filepath) {
  return array(
    'Content-Disposition: attachment; filename="'. basename($filepath) .'"'
  );
}

?>