Hooks and Filters

Lesson 10 of 15 4 min read
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The plugin provides several WordPress filters for customizing behavior.

md_page_blocks_builder_post_types

Controls which post types the builder is available on.

add_filter( 'md_page_blocks_builder_post_types', function( $post_types ) {
    $post_types[] = 'product';
    $post_types[] = 'landing_page';
    return $post_types;
} );

Parameters

  • $post_types (array) – Array of post type slugs. Default includes whatever is configured in the plugin settings (defaults to ['post', 'page']).

Return value

An array of post type slugs. The array is sanitized after filtering: each value is passed through sanitize_key, empty values are removed, and duplicates are stripped.

When it runs

This filter runs every time the plugin needs to check allowed post types: when rendering the admin bar link, when validating builder access, and when checking if the Gutenberg block should be available for a post type.

md_page_blocks_builder_preview_injection

Injects custom HTML, CSS, and JavaScript into the visual builder’s preview iframe. This is useful for adding framework CSS, custom fonts, analytics scripts, or any other assets that your sections depend on but aren’t part of the theme.

add_filter( 'md_page_blocks_builder_preview_injection', function( $injection, $post_id ) {
    // Add a custom meta tag to the preview head
    $injection['headHtml'] .= '<meta name="pb-preview" content="1">';

    // Add custom CSS
    $injection['css'] .= '.pb-preview-note { display: none; }';

    // Add a JavaScript variable available in the preview
    $injection['jsHead'] .= 'window.PB_PREVIEW = true;';

    // Load a custom stylesheet
    $injection['headHtml'] .= '<link rel="stylesheet" href="https://example.com/custom.css">';

    // Add HTML at the start of the preview body
    $injection['bodyStartHtml'] .= '<div class="preview-wrapper">';

    // Add HTML at the end of the preview body
    $injection['bodyEndHtml'] .= '</div>';

    // Add JavaScript that runs after all content
    $injection['jsFooter'] .= 'console.log("Preview loaded");';

    return $injection;
}, 10, 2 );

Parameters

  • $injection (array) – An associative array with these keys, all defaulting to empty strings.
    • headHtml – Raw HTML injected into the <head> of the preview document.
    • bodyStartHtml – Raw HTML injected at the start of the <body>.
    • bodyEndHtml – Raw HTML injected at the end of the <body>.
    • css – CSS injected as an inline <style> tag in the head.
    • jsHead – JavaScript injected as an inline <script> in the head.
    • jsFooter – JavaScript injected as an inline <script> at the end of the body.
  • $post_id (int) – The ID of the post being edited.

Return value

The modified injection array. All values are cast to strings.

When it runs

This filter runs when the visual builder loads and the injection data is passed to JavaScript as part of the localized script configuration.

gt_page_blocks_can_execute_php

Controls whether PHP code execution is allowed in a Page Block’s content.

// Disable PHP execution entirely
add_filter( 'gt_page_blocks_can_execute_php', '__return_false' );

// Only allow PHP execution for specific users
add_filter( 'gt_page_blocks_can_execute_php', function( $can_execute, $content ) {
    return current_user_can( 'manage_options' );
}, 10, 2 );

Parameters

  • $can_execute (bool) – Whether PHP execution is allowed. The default logic allows execution if the current user has manage_options capability OR if the request is a frontend page load (not admin, not AJAX, not REST API).
  • $content (string) – The raw HTML content that contains PHP code.

Return value

A boolean. If false, PHP tags in the content are stripped (removed) before rendering.

When it runs

This filter runs every time a Page Block with phpExec enabled is rendered, both on the frontend and during preview requests.

WordPress Standard Hooks

The plugin also interacts with several standard WordPress hooks.

block_categories_all

The plugin adds a “Marketers Delight” block category if it doesn’t already exist. If you’re using the Marketers Delight theme (which already registers this category), the plugin detects the existing category and doesn’t duplicate it.

theme_page_templates

The plugin registers its two page templates (“Page Blocks Builder” and “Full Page Builder”) so they appear in the template selector for all supported post types.

template_include

The plugin intercepts template loading at two levels.

  • Priority 0: Checks for the builder route (?build=page-blocks) and loads the builder shell template.
  • Default priority: Checks if the post uses a plugin-provided page template and loads it from the plugin’s templates/ directory.

admin_bar_menu

The plugin adds the “Page Blocks Builder” link to the admin bar at priority 80, nested under the “Edit” node when available.

wp_footer

The plugin outputs queued footer scripts during wp_footer at priority 99.

AJAX Actions

The plugin registers two AJAX actions.

md_page_blocks_builder_apply

Saves sections from the visual builder to the post content. Requires a valid builder nonce and edit_post capability.

md_page_blocks_builder_preview

Renders a server-side preview of sections. Requires a valid preview nonce and edit_post capability.

Both actions are authenticated-only (registered via wp_ajax_ hooks, not wp_ajax_nopriv_).