Feature Request: User-defined URIs to purge with post cache

[raamdev]

It would be nice if a site-owner could specify a custom list of URIs that should be purged when a post is published/modified.

This would be similar to the URI Exclusion feature, except these URIs would be cached normally and cleared the same way the Home Page and Posts Page caches can be cleared.

Such a feature would be useful in scenarios where the site has pages with custom archive views that need to be cleared when a post is published/modified.

[jaswrks]

Awesome idea! Agree 😺

[raamdev]

Temporary Workaround

If you need to clear a specific Post / Page whenever the cache is automatically cleared, you can do this by adding some code to your theme's functions.php file (or to an MU-Plugin). For more information, please see Clearing the Cache Dynamically.

[martinperreault]

I also would like to see this feature added to the plugin. Thank you!

[raamdev]

Noting here that this feature (User-defined URIs to purge with post cache) would also solve the scenario described below:

@bridgeport writes (in #553 (comment))...

There's an existing option to 'Auto-Clear Designated "Posts Page"', but I think another to clear all "post" types would be useful. An example use case:

Let's say single blogs posts have a sidebar of most recent posts. If a new post is published or modified, it would shift the ordering of these sidebar items. But since ZenCache doesn't automatically purge other posts, their sidebar content would be stale. The entire cache would have to be purged, or deleted via FTP in order for these recent items to be updated.

@raamdev writes (in #553 (comment))...

a better solution to this issue would be to add support for User-Defined URIs to clear whenever a Post is cleared (see #111), and to support wildcards with that feature so that a site owner could, for example, specify /blog/* to clear all cache files for URIs under /blog/ (i.e., all Posts) whenever any Post cache is cleared.

[clavaque]

+1 for this feature. I have a custom archive page with this https://wordpress.org/plugins/clean-my-archives/ and right now need to purge it manually after publishing a new post.

I'll use the dynamic purge workaround you suggested, but think that a box for custom URIs in the Automatic Cache Clearing settings would make a lot of sense.

Thanks!

[jaswrks]

Next Actions

• New feature branch: feature/111 in the websharks/zencache-pro repo.

• After this line add:

  'cache_clear_urls',

• After this line add:

  'cache_clear_urls' => '', // Line-delimited list of URLs.

• In this directory create a new file with the name: WcpUrlUtils.php

  <?php
  /*[pro strip-from="lite"]*/
  namespace WebSharks\ZenCache\Pro;
  
  /*
  * Automatically clears cache files for a list of custom URLs.
  *
  * @since 15xxxx Adding support for a custom list of URLs.
  *
  * @throws \Exception If a clear failure occurs.
  *
  * @return int Total files cleared by this routine (if any).
  *
  * @note Unlike many of the other `auto_` methods, this one is NOT currently
  *    attached to any hooks. However, it is called upon by other routines attached to hooks.
  */
  $self->autoClearUrlsCache = function () use ($self) {
      $counter = 0; // Initialize.
  
      if (!is_null($done = &$self->cacheKey('autoClearUrlsCache'))) {
          return $counter; // Already did this.
      }
      $done = true; // Flag as having been done.
  
      if (!$self->options['enable']) {
          return $counter; // Nothing to do.
      }
      if (!$self->options['cache_clear_urls']) {
          return $counter; // Nothing to do.
      }
      if (!is_dir($cache_dir = $self->cacheDir())) {
          return $counter; // Nothing to do.
      }
      foreach (preg_split('/['."\r\n".']+/', $self->options['cache_clear_urls'], null, PREG_SPLIT_NO_EMPTY) as $_url) {
          if (stripos($_url, 'http') === 0) {
              $_regex = $self->buildHostCachePathRegex($_url);
              $counter += $self->clearFilesFromHostCacheDir($_regex);
          }
      } unset($_url, $_regex); // Housekeeping.
  
      if ($counter && is_admin() && (!IS_PRO || $self->options['change_notifications_enable'])) {
          $self->enqueueNotice('<img src="'.esc_attr($self->url('/src/client-s/images/clear.png')).'" style="float:left; margin:0 10px 0 0; border:0;" />'.
                                sprintf(__('<strong>%1$s:</strong> detected changes. Found %2$s in the cache matching a custom list of URLs; auto-clearing.', SLUG_TD), esc_html(NAME), esc_html($self->i18nFiles($counter))));
      }
      return $counter;
  };
  /*[/pro]*/

• After this line add the following:

  /*[pro strip-from="lite"]*/
  $counter += $self->autoClearUrlsCache();
  /*[/pro]*/

• After this line add the following:

  if (IS_PRO || $this->plugin->isProPreview()) {
      echo '<h4 style="margin-bottom:0;">'.__('Auto-Clear a List of Custom URLs Too?', SLUG_TD).'</h4>'."\n";
      echo '<p style="margin-top:2px;">'.sprintf(__('When you update a Post/Page, approve a Comment, or make other changes where %1$s can detect that a Post/Page cache should be cleared to keep your site up-to-date; then %1$s will also clear a list of custom URLs that you list here. <strong>Please list one URL per line.</strong>', SLUG_TD), esc_html(NAME)).'</p>'."\n";
      echo '<p><textarea name="'.esc_attr(GLOBAL_NS).'[saveOptions][cache_clear_urls]" spellcheck="false" wrap="off" rows="5">'.format_to_edit($this->plugin->options['cache_clear_urls']).'</textarea></p>'."\n";
  }

• Submit PR.

[jaswrks]

@kristineds While working on this issue, you can take note of the fact that ZenCache uses a lot of PHP Closures. You can learn more about Closures here: http://php.net/manual/en/functions.anonymous.php

In the code above, $self->autoClearUrlsCache = function(){}; is a Closure.

[raamdev]

Next Pro Release Changelog:

• New Feature! It's now possible to specify a list of Custom URLs whose cache files should be cleared whenever you update a Post/Page, approve a Comment, or make other changes where ZenCache detects that a Post/Page cache should be cleared to keep your site up-to-date. See ZenCache → Plugin Options → Automatic Cache Clearing → Misc. Auto-Clear Options → Auto-Clear a List of Custom URLs Too? Props @kristineds. See Issue #111.

[raamdev]

ZenCache v151114 has been released and includes changes from this GitHub Issue. See the v151114 announcement for further details.

---

This issue will now be locked to further updates. If you have something to add related to this GitHub Issue, please open a new GitHub Issue and reference this one (#111).