pathologic.module in Pathologic 8

Pathologic text filter for Drupal.

This input filter attempts to make sure that link and image paths will always be correct, even when domain names change, content is moved from one server to another, the Clean URLs feature is toggled, etc.

@todo for Pathlogic 8.x-2.x

• Account for new way dirty URLs are done (no more clean_url variable)
• - We can now tell url() to create clean or dirty URLs regardless of current status!
• - (lol jk no more url() - but maybe the equivalent code is still there)
• - Our path parsing code needs to account for both new and old dirty URL styles
• - Option to force output of clean or dirty URLs?
• Move _pathologic_filter() code into the actual filter class
• Do DOM object manipulation instead of preg_replace(). It's what core filters are doing now.
• UrlHelper::Parse() instead of parse_url()?
• Alter hook alters Drupal\Core\Url object instead of method parameters.

File

pathologic.module

<?php

/**
 * @file
 * Pathologic text filter for Drupal.
 *
 * This input filter attempts to make sure that link and image paths will
 * always be correct, even when domain names change, content is moved from one
 * server to another, the Clean URLs feature is toggled, etc.
 *
 * @todo for Pathlogic 8.x-2.x
 * - Account for new way dirty URLs are done (no more clean_url variable)
 * - - We can now tell url() to create clean or dirty URLs regardless of current
 *     status!
 * - - (lol jk no more url() - but maybe the equivalent code is still there)
 * - - Our path parsing code needs to account for both new and old dirty URL
 *     styles
 * - - Option to force output of clean or dirty URLs?
 * - Move _pathologic_filter() code into the actual filter class
 * - Do DOM object manipulation instead of preg_replace(). It's what core
 *   filters are doing now.
 * - UrlHelper::Parse() instead of parse_url()?
 * - Alter hook alters Drupal\Core\Url object instead of method parameters.
 */
use Drupal\Component\Utility\Html;
use Drupal\Component\Utility\Unicode;
use Drupal\Core\Url;

/**
 * Pathologic filter callback.
 *
 * @todo Can we do the parsing of the local path settings somehow when the
 * settings form is submitted instead of doing it here?
 */
function _pathologic_filter($text, $settings, $hash) {

  // Get the base URL and explode it into component parts. We add these parts
  // to the exploded local paths settings later.
  global $base_url;
  $base_url_parts = parse_url($base_url . '/');

  // Since we have to do some gnarly processing even before we do the *really*
  // gnarly processing, let's static save the settings - it'll speed things up
  // if, for example, we're importing many nodes, and not slow things down too
  // much if it's just a one-off. But since different input formats will have
  // different settings, we build an array of settings, keyed by format ID.
  $cached_settings =& drupal_static(__FUNCTION__, []);
  if (!isset($cached_settings[$hash])) {
    $settings['local_paths_exploded'] = [];
    if ($settings['local_paths'] !== '') {

      // Build an array of the exploded local paths for this format's settings.
      // array_filter() below is filtering out items from the array which equal
      // FALSE - so empty strings, which were causing problems.
      // @see http://drupal.org/node/1727492
      $local_paths = array_filter(array_map('trim', explode("\n", $settings['local_paths'])));
      foreach ($local_paths as $local) {
        $parts = parse_url($local);

        // Okay, what the hellish "if" statement is doing below is checking to
        // make sure we aren't about to add a path to our array of exploded
        // local paths which matches the current "local" path. We consider it
        // not a match, if…
        // @todo: This is pretty horrible. Can this be simplified?
        if (isset($parts['host']) && ($parts['host'] !== $base_url_parts['host'] || ((isset($parts['path']) xor isset($base_url_parts['path'])) || isset($parts['path']) && isset($base_url_parts['path']) && $parts['path'] !== $base_url_parts['path'])) || !isset($parts['host']) && (!isset($parts['path']) || !isset($base_url_parts['path']) || $parts['path'] !== $base_url_parts['path'])) {

          // Add it to the list.
          $settings['local_paths_exploded'][] = $parts;
        }
      }
    }

    // Now add local paths based on "this" server URL.
    $settings['local_paths_exploded'][] = [
      'path' => $base_url_parts['path'],
    ];
    $settings['local_paths_exploded'][] = [
      'path' => $base_url_parts['path'],
      'host' => $base_url_parts['host'],
    ];

    // We'll also just store the host part separately for easy access.
    $settings['base_url_host'] = $base_url_parts['host'];
    $cached_settings[$hash] = $settings;
  }

  // Take note of which settings in the settings array should apply.
  $cached_settings['current_settings'] =& $cached_settings[$hash];

  // Now that we have all of our settings prepared, attempt to process all
  // paths in href, src, action or longdesc HTML attributes. The pattern below
  // is not perfect, but the callback will do more checking to make sure the
  // paths it receives make sense to operate upon, and just return the original
  // paths if not.
  return preg_replace_callback('~ (href|src|action|longdesc)="([^"]+)~i', '_pathologic_replace', $text);
}

/**
 * Process and replace paths. preg_replace_callback() callback.
 */
function _pathologic_replace($matches) {

  // Get the base path.
  global $base_path;

  // Get the settings for the filter. Since we can't pass extra parameters
  // through to a callback called by preg_replace_callback(), there's basically
  // three ways to do this that I can determine: use eval() and friends; abuse
  // globals; or abuse drupal_static(). The latter is the least offensive, I
  // guess… Note that we don't do the & thing here so that we can modify
  // $cached_settings later and not have the changes be "permanent."
  $cached_settings = drupal_static('_pathologic_filter');

  // If it appears the path is a scheme-less URL, prepend a scheme to it.
  // parse_url() cannot properly parse scheme-less URLs. Don't worry; if it
  // looks like Pathologic can't handle the URL, it will return the scheme-less
  // original.
  // @see https://drupal.org/node/1617944
  // @see https://drupal.org/node/2030789
  if (strpos($matches[2], '//') === 0) {
    if (\Drupal::request()
      ->isSecure()) {
      $matches[2] = 'https:' . $matches[2];
    }
    else {
      $matches[2] = 'http:' . $matches[2];
    }
  }

  // Now parse the URL after reverting HTML character encoding.
  // @see http://drupal.org/node/1672932
  $original_url = htmlspecialchars_decode($matches[2]);

  // …and parse the URL
  $parts = parse_url($original_url);

  // Do some more early tests to see if we should just give up now.
  if (empty($parts) || isset($parts['scheme']) && !in_array($parts['scheme'], \Drupal::config('pathologic.settings')
    ->get('scheme_whitelist')) || isset($parts['fragment']) && count($parts) === 1) {

    // Give up by "replacing" the original with the same.
    return $matches[0];
  }
  if (isset($parts['path'])) {

    // Undo possible URL encoding in the path.
    // @see http://drupal.org/node/1672932
    $parts['path'] = rawurldecode($parts['path']);
  }
  else {
    $parts['path'] = '';
  }

  // Check to see if we're dealing with a file.
  // @todo Should we still try to do path correction on these files too?
  if (isset($parts['scheme']) && $parts['scheme'] === 'files') {

    // Path Filter "files:" support. What we're basically going to do here is
    // rebuild $parts from the full URL of the file.
    $new_parts = parse_url(file_create_url(\Drupal::config('system.file')
      ->get('default_scheme') . '://' . $parts['path']));

    // If there were query parts from the original parsing, copy them over.
    if (!empty($parts['query'])) {
      $new_parts['query'] = $parts['query'];
    }
    $new_parts['path'] = rawurldecode($new_parts['path']);
    $parts = $new_parts;

    // Don't do language handling for file paths.
    $cached_settings['is_file'] = TRUE;
  }
  else {
    $cached_settings['is_file'] = FALSE;
  }

  // Let's also bail out of this doesn't look like a local path.
  $found = FALSE;

  // Cycle through local paths and find one with a host and a path that matches;
  // or just a host if that's all we have; or just a starting path if that's
  // what we have.
  foreach ($cached_settings['current_settings']['local_paths_exploded'] as $exploded) {

    // If a path is available in both…
    if (isset($exploded['path']) && isset($parts['path']) && strpos($parts['path'], $exploded['path']) === 0 && (isset($exploded['host']) && isset($parts['host']) && $exploded['host'] === $parts['host'] || !isset($exploded['host']) && !isset($parts['host']))) {

      // Remove the shared path from the path. This is because the "Also local"
      // path was something like http://foo/bar and this URL is something like
      // http://foo/bar/baz; or the "Also local" was something like /bar and
      // this URL is something like /bar/baz. And we only care about the /baz
      // part.
      $parts['path'] = mb_substr($parts['path'], mb_strlen($exploded['path']));
      $found = TRUE;

      // Break out of the foreach loop
      break;
    }
    elseif (isset($parts['host']) && !isset($exploded['path']) && isset($exploded['host']) && $exploded['host'] === $parts['host']) {

      // No further editing; just continue
      $found = TRUE;

      // Break out of foreach loop
      break;
    }
    elseif (!isset($parts['host']) && (!isset($exploded['path']) || $exploded['path'] === $base_path)) {
      $found = TRUE;
    }
  }

  // If the path is not within the drupal root return original url, unchanged
  if (!$found) {
    return $matches[0];
  }

  // Okay, format the URL.
  // If there's still a slash lingering at the start of the path, chop it off.
  $parts['path'] = ltrim($parts['path'], '/');

  // Examine the query part of the URL. Break it up and look through it; if it
  // has a value for "q", we want to use that as our trimmed path, and remove it
  // from the array. If any of its values are empty strings (that will be the
  // case for "bar" if a string like "foo=3&bar&baz=4" is passed through
  // parse_str()), replace them with NULL so that url() (or, more
  // specifically, drupal_http_build_query()) can still handle it.
  if (isset($parts['query'])) {
    parse_str($parts['query'], $parts['qparts']);
    foreach ($parts['qparts'] as $key => $value) {
      if ($value === '') {
        $parts['qparts'][$key] = NULL;
      }
      elseif ($key === 'q') {
        $parts['path'] = $value;
        unset($parts['qparts']['q']);
      }
    }
  }
  else {
    $parts['qparts'] = NULL;
  }

  // If we don't have a path yet, bail out.
  if (!isset($parts['path'])) {
    return $matches[0];
  }

  // If this looks like a D8-style unclean URL, crop off the "index.php/" from
  // the beginning.
  if (strpos($parts['path'], 'index.php/') === 0) {
    $parts['path'] = substr($parts['path'], 10);
  }

  // If we didn't previously identify this as a file, check to see if the file
  // exists now that we have the correct path relative to DRUPAL_ROOT
  if (!$cached_settings['is_file']) {
    $cached_settings['is_file'] = !empty($parts['path']) && is_file(DRUPAL_ROOT . '/' . $parts['path']);
  }

  // Okay, deal with language stuff.
  // Let's see if we can split off a language prefix from the path.
  if (\Drupal::moduleHandler()
    ->moduleExists('language')) {

    // This logic is based on
    // \Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrl::getLangcode().
    $languages = \Drupal::languageManager()
      ->getLanguages();
    $config = \Drupal::config('language.negotiation')
      ->get('url');
    $request_path = urldecode(trim($parts['path'], '/'));
    $path_args = explode('/', $request_path);
    $prefix = array_shift($path_args);

    // Search for prefix within added languages.
    foreach ($languages as $language) {
      if (isset($config['prefixes'][$language
        ->getId()]) && $config['prefixes'][$language
        ->getId()] == $prefix) {
        $parts['path'] = implode('/', $path_args);
        $parts['language_obj'] = $language;
        break;
      }
    }
  }

  // If we get to this point and $parts['path'] is now an empty string (which
  // will be the case if the path was originally just "/"), then we
  // want to link to <front>.
  if ($parts['path'] === '') {
    $parts['path'] = '<front>';
  }

  // Build the parameters we will send to url()
  $url_params = [
    'path' => $parts['path'],
    'options' => [
      'query' => $parts['qparts'],
      'fragment' => isset($parts['fragment']) ? $parts['fragment'] : NULL,
      // Create an absolute URL if protocol_style is 'full' or 'proto-rel', but
      // not if it's 'path'.
      'absolute' => $cached_settings['current_settings']['protocol_style'] !== 'path',
      // If we seem to have found a language for the path, pass it along to
      // url(). Otherwise, ignore the 'language' parameter.
      'language' => isset($parts['language_obj']) ? $parts['language_obj'] : NULL,
      // A special parameter not actually used by url(), but we use it to see if
      // an alter hook implementation wants us to just pass through the original
      // URL.
      'use_original' => FALSE,
    ],
  ];

  // Add the original URL to the parts array
  $parts['original'] = $original_url;

  // Now alter!
  // @see http://drupal.org/node/1762022
  \Drupal::moduleHandler()
    ->alter('pathologic', $url_params, $parts, $cached_settings);

  // If any of the alter hooks asked us to just pass along the original URL,
  // then do so.
  if ($url_params['options']['use_original']) {
    return $matches[0];
  }

  // Now to build the URL. Drumroll, please…
  if ($parts['path'] == '<front>') {
    $url = Url::fromRoute('<front>', [], $url_params['options'])
      ->toString();
  }
  else {
    try {
      $url = Url::fromUri('base://' . $url_params['path'], $url_params['options'])
        ->toString();
    } catch (\Exception $e) {

      // In case of an error, e.g. completely invalid URL, return it unchanged.
      return $matches[0];
    }
  }

  // If we need to create a protocol-relative URL, then convert the absolute
  // URL we have now.
  if ($cached_settings['current_settings']['protocol_style'] === 'proto-rel') {

    // Now, what might have happened here is that url() returned a URL which
    // isn't on "this" server due to a hook_url_outbound_alter() implementation.
    // We don't want to convert the URL in that case. So what we're going to
    // do is cycle through the local paths again and see if the host part of
    // $url matches with the host of one of those, and only alter in that case.
    $url_parts = parse_url($url);
    if (!empty($url_parts['host']) && $url_parts['host'] === $cached_settings['current_settings']['base_url_host']) {
      $url = _pathologic_url_to_protocol_relative($url);
    }
  }

  // Apply HTML character encoding, as is required for HTML attributes.
  // @see http://drupal.org/node/1672932
  $url = Html::escape($url);

  // $matches[1] will be the tag attribute; src, href, etc.
  return " {$matches[1]}=\"{$url}";
}

/**
 * Convert a full URL with a protocol to a protocol-relative URL.
 *
 * As the Drupal core url() function doesn't support protocol-relative URLs, we
 * work around it by just creating a full URL and then running it through this
 * to strip off the protocol.
 *
 * Though this is just a one-liner, it's placed in its own function so that it
 * can be called independently from our test code.
 */
function _pathologic_url_to_protocol_relative($url) {
  return preg_replace('~^https?://~', '//', $url);
}

Functions

Name	Description
_pathologic_filter	Pathologic filter callback.
_pathologic_replace	Process and replace paths. preg_replace_callback() callback.
_pathologic_url_to_protocol_relative	Convert a full URL with a protocol to a protocol-relative URL.