Filters

Introduction

Filters in Botble CMS are hooks that allow you to modify data during the execution of the application. Unlike actions, which simply execute code at specific points, filters are designed to transform data and return a modified version.

Filters are used throughout Botble CMS to allow plugins and themes to modify content, settings, and other data without changing core files. They provide a powerful way to customize the behavior of the CMS in a modular and maintainable way.

Using Filters

Adding a Filter

To hook into a filter, use the add_filter() function:

add_filter(string|array $tag, callable $callback, int $priority = 20, int $accepted_args = 1)

Parameters

• $tag: (string|array) The name of the filter(s) to hook into. Can be a single filter name or an array of filter names.
• $callback: (callable) The function or method to be called when the filter is applied.
• $priority: (int) Optional. Used to specify the order in which callbacks are executed. Lower numbers = earlier execution. Default is 20.
• $accepted_args: (int) Optional. The number of arguments your callback accepts. Default is 1.

Example

// In a service provider's boot method or theme functions.php
add_filter('base_filter_public_single_data', function ($data, $model) {
    if ($model instanceof \Botble\Blog\Models\Post) {
        // Modify post data
        $data['custom_field'] = get_meta_data($model, 'custom_field', true);
    }

    return $data;
}, 20, 2);

Applying a Filter

To apply a filter (usually done in core code), use the apply_filters() function:

$modified_value = apply_filters(string $tag, mixed $value, ...$args)

Parameters

• $tag: (string) The name of the filter to apply.
• $value: (mixed) The value to filter.
• $args: (mixed) Optional. Additional arguments to pass to the callbacks hooked to the filter.

Example

// In a controller or service
public function getData($id)
{
    $post = Post::findOrFail($id);
    $data = $post->toArray();

    // Apply a filter to the data
    $data = apply_filters('blog_post_data', $data, $post);

    return $data;
}

Removing a Filter

To remove a previously added filter, use the remove_filter() function:

remove_filter(string $tag)

Example

// Remove all callbacks for a filter
remove_filter('base_filter_public_single_data');

Common Filter Hooks

Botble CMS provides many filter hooks that you can use in your plugins and themes. Here are some of the most commonly used ones:

Content Filters

• BASE_FILTER_PUBLIC_SINGLE_DATA: Modify data for a single item on the front end.

  add_filter(BASE_FILTER_PUBLIC_SINGLE_DATA, function ($data, $model) {
      // Modify single item data
      return $data;
  }, 20, 2);

• BASE_FILTER_BEFORE_GET_SINGLE: Modify query before getting a single item.

  add_filter(BASE_FILTER_BEFORE_GET_SINGLE, function ($query, $model) {
      // Modify query
      return $query;
  }, 20, 2);

• BASE_FILTER_BEFORE_GET_BY_SLUG: Modify query before getting an item by slug.

  add_filter(BASE_FILTER_BEFORE_GET_BY_SLUG, function ($query, $model, $slug) {
      // Modify query
      return $query;
  }, 20, 3);

Form Filters

• BASE_FILTER_BEFORE_RENDER_FORM: Modify form before rendering.

  add_filter(BASE_FILTER_BEFORE_RENDER_FORM, function ($form, $data) {
      // Modify form
      return $form;
  }, 20, 2);

• BASE_FILTER_AFTER_FORM_CREATED: Modify form after creation.

  add_filter(BASE_FILTER_AFTER_FORM_CREATED, function ($form, $data) {
      // Modify form
      return $form;
  }, 20, 2);

• BASE_FILTER_FORM_EDITOR_BUTTONS: Modify editor buttons.

  add_filter(BASE_FILTER_FORM_EDITOR_BUTTONS, function ($buttons) {
      // Add or remove buttons
      $buttons[] = 'myCustomButton';
      return $buttons;
  }, 20, 1);

Dashboard Filters

• DASHBOARD_FILTER_ADMIN_LIST: Modify dashboard widgets.

  add_filter(DASHBOARD_FILTER_ADMIN_LIST, function ($widgets, $widgetSettings) {
      // Add or modify dashboard widgets
      return $widgets;
  }, 20, 2);

• DASHBOARD_FILTER_ADMIN_NOTIFICATIONS: Modify dashboard notifications.

  add_filter(DASHBOARD_FILTER_ADMIN_NOTIFICATIONS, function ($notifications) {
      // Add or modify notifications
      return $notifications . '<div class="alert alert-info">Custom notification</div>';
  }, 20, 1);

Table Filters

• BASE_FILTER_TABLE_HEADINGS: Modify table headings.

  add_filter(BASE_FILTER_TABLE_HEADINGS, function ($headings, $table) {
      // Modify table headings
      return $headings;
  }, 20, 2);

• BASE_FILTER_TABLE_BUTTONS: Modify table buttons.

  add_filter(BASE_FILTER_TABLE_BUTTONS, function ($buttons, $table) {
      // Add or modify table buttons
      return $buttons;
  }, 20, 2);

• BASE_FILTER_GET_LIST_DATA: Modify data for tables.

  add_filter(BASE_FILTER_GET_LIST_DATA, function ($data, $model) {
      // Modify list data
      return $data;
  }, 20, 2);

Menu Filters

• BASE_FILTER_DASHBOARD_MENU: Modify dashboard menu.

  add_filter(BASE_FILTER_DASHBOARD_MENU, function ($menu) {
      // Modify dashboard menu
      return $menu;
  }, 20, 1);

• BASE_FILTER_APPEND_MENU_NAME: Append text to menu names.

  add_filter(BASE_FILTER_APPEND_MENU_NAME, function ($name, $menuId) {
      // Append text to menu name
      if ($menuId === 'cms-plugins-blog') {
          return $name . ' <span class="badge badge-success">New</span>';
      }
      return $name;
  }, 20, 2);

Enum Filters

• BASE_FILTER_ENUM_ARRAY: Modify enum values.

  add_filter(BASE_FILTER_ENUM_ARRAY, function ($values, $class) {
      if ($class === \Botble\Base\Enums\BaseStatusEnum::class) {
          $values['PENDING'] = 'pending';
      }
      return $values;
  }, 20, 2);

• BASE_FILTER_ENUM_LABEL: Modify enum labels.

  add_filter(BASE_FILTER_ENUM_LABEL, function ($label, $class, $value) {
      if ($class === \Botble\Base\Enums\BaseStatusEnum::class && $value === 'pending') {
          return 'Waiting for approval';
      }
      return $label;
  }, 20, 3);

Best Practices

1. Always Return a Value: Filters must always return a value, even if you don't modify it.

2. Use Appropriate Priority: Choose a priority that makes sense for your filter. Lower numbers run earlier.

3. Accept Only Needed Arguments: Only specify the number of arguments your callback actually needs.

4. Check Types: Always check the type of data you're filtering to avoid errors.

5. Document Your Filters: If you're creating new filter hooks, document them clearly for other developers.

6. Use Service Providers: Register your filter hooks in service providers' boot methods for better organization.

Creating Custom Filter Hooks

You can create your own filter hooks in your plugins or themes:

// In your controller or service
public function getData($id)
{
    $data = YourModel::findOrFail($id)->toArray();

    // Apply a custom filter
    $data = apply_filters('my_plugin_get_data', $data, $id);

    return $data;
}

Other developers can then hook into your custom filter:

add_filter('my_plugin_get_data', function ($data, $id) {
    // Modify the data
    $data['custom_field'] = 'Custom value';

    return $data;
}, 20, 2);