Handling AMP Legacy Themes

Although the plugin provides capabilities that enable you to power your whole site with AMP in any of the three template modes, the plugin also provides the legacy theme used for Reader mode for backwards compatibility.

Customizer Panel #

The plugin adds an “AMP” panel in the Customizer, which you can use to tweak various parts of the default template like colors.

Disabling the AMP Customizer Settings #

If you’re using a completely custom template, you may want to disable the AMP Customizer Settings:

add_filter( 'amp_customizer_is_enabled', '__return_false' );Code language: JavaScript (javascript)

Note that this needs to be called before the after_setup_theme hook to work.

Where to Put Your Code #

The code snippets below and any other code-level customizations should happen in one of the following locations.

If you’re using an off-the-shelf theme (like from the WordPress.org Theme Directory):

• A child theme.
• A custom plugin that you activate via the Dashboard.
• An mu-plugin.

If you’re using a custom theme:

• functions.php (or via a ‘require’ call to files that load from functions.php).
• Any of the options above.

Theme Mods #

The default template will attempt to draw from various theme mods, such as site icon, if supported by the active theme.

Site Icon #

If you add a site icon, we will automatically replace the WordPress logo in the template. Or if you’d prefer you can do it programmatically:

add_filter(
	'amp_post_template_data', 
	function ( $data ) {
		// Ideally a 32x32 image
		$data['site_icon_url'] = get_stylesheet_directory_uri() . '/images/amp-site-icon.png';
		return $data;
	}
);Code language: PHP (php)

Logo Only #

If you want to hide the site text and just show a logo, use the amp_post_template_css action. The following colors the title bar black, hides the site title, and replaces it with a centered logo:

add_action(
	'amp_post_template_css',
	function () {
		// only CSS here please...
		?>
		header.amp-wp-header {
			padding: 12px 0;
			background: #000;
		}
		header.amp-wp-header a {
			background-image: url( 'https://example.com/path/to/logo.png' );
			background-repeat: no-repeat;
			background-size: contain;
			display: block;
			height: 28px;
			width: 94px;
			margin: 0 auto;
			text-indent: -9999px;
		}
		<?php
	}
);Code language: PHP (php)

Note: you will need to adjust the colors and sizes based on your brand.

Template Tweaks #

Featured Image #

The default template displays the featured image. If you don’t want to display the featured image in your amp page, use the following code:

add_filter( 
	'amp_post_template_data', 
	function ( $data ) {
		$data['featured_image'] = false;
		return $data;
	} 
);Code language: PHP (php)

Content Width #

By default, your theme’s $content_width value will be used to determine the size of the amp content well. You can change this:

add_filter( 'amp_content_max_width', function () {
	return 1200;
} );Code language: JavaScript (javascript)

Template Data #

Use the amp_post_template_data filter to override default template data. The following changes the placeholder image used for iframes to a file located in the current theme:

add_filter( 'amp_post_template_data', function ( $data ) {
	$data[ 'placeholder_image_url' ] = get_stylesheet_directory_uri() . '/images/amp-iframe-placeholder.png';
	return $data;
} );Code language: PHP (php)

Note: The path must pass the default criteria set out by validate_file and must be somewhere in a subfolder of WP_CONTENT_DIR.

Schema.org (JSON) Metadata #

The plugin adds some default metadata to enable “Rich Snippet” support. You can modify this using the amp_post_template_metadata filter. The following changes the type annotation to NewsArticle (from the default BlogPosting) and overrides the default Publisher Logo.

add_filter( 'amp_post_template_metadata', function ( $metadata ) {
	$metadata['@type'] = 'NewsArticle';

	$metadata['publisher']['logo'] = array(
		'@type' => 'ImageObject',
		'url' => get_template_directory_uri() . '/images/my-amp-metadata-logo.png',
		'height' => 60,
		'width' => 600,
	);

	return $metadata;
}, 10, 2 );Code language: PHP (php)

Template Meta (Author, Date, etc.) #

For the meta section of the template (i.e. author, date, taxonomies, etc.), you can override templates for the existing sections, remove them, add new ones.

Example: Override Author Template from Theme

Create a folder in your theme called amp and add a file called meta-author.php with the following:

<li class="xyz-byline">
	<span>Anonymous</span>
</li>
Code language: HTML, XML (xml)

Replace the contents, as needed.

Example: Adding custom templates for homepage and page for posts

As for v0.6 pages are supported by the plugin, including the homepage (page on front) and page for posts (blog). After enabling “page” post type support in the AMP general settings, all pages will be enabled for AMP by default, unless the page is the homepage, the blog page, or a page that is assigned to a custom template. (You can auto opt-in to AMP support for all pages via add_filter( 'amp_post_status_default_enabled', '__return_true' ).) To opt-in these pages for AMP, just enable support via the AMP support toggle in the page’s publish metabox. The homepage can re-use the single.php template as a default, but the page for posts should get a custom template assigned so that the list of posts (The Loop) is present. To modify the template for the homepage or page for posts, put the following in your theme’s functions.php:

add_filter( 'amp_post_template_file', function ( $template, $template_type, $post ) {
	if ( 'page' === $template_type && 'page' === get_option( 'show_on_front' ) ) {
		if ( (int) get_option( 'page_on_front' ) === $post->ID ) {
			$template = dirname( __FILE__ ) . '/amp/home.php';
		} elseif ( (int) get_option( 'page_for_posts' ) === $post->ID ) {
			$template = dirname( __FILE__ ) . '/amp/blog.php';
		}
	}
	return $template;
}, 10, 3 );Code language: PHP (php)

Then you can add an amp/home.php which is basically a fork of the plugin’s bundled single.phpand the same for amp/blog.php with this key addition:

<ul>
	<?php while ( have_posts() ) : the_post(); ?>
		<li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
	<?php endwhile; ?>
</ul>
<?php the_posts_pagination(); ?>Code language: HTML, XML (xml)

Example: Override Taxonomy Template via filter

This will load the file t/meta-custom-tax.php for the taxonomy section:

add_filter( 'amp_post_template_file', functionn( $file, $type, $post ) {
	if ( 'meta-taxonomy' === $type ) {
		$file = dirname( __FILE__ ) . '/t/meta-custom-tax.php';
	}
	return $file;
}, 10, 3 );Code language: PHP (php)

In t/meta-custom-tax.php, you can add something like the following to replace the default category and tags with your custom author taxonomy:

<li class="xyz-tax-authors">
	<?php echo get_the_term_list( $this->get( 'post_id' ), 'xyz-author', '', ', ' ); ?>
</li>Code language: HTML, XML (xml)

Example: Remove Author from header_meta

This will completely remove the author section:

add_filter( 'amp_post_article_header_meta', function ( $meta_parts ) {
	foreach ( array_keys( $meta_parts, 'meta-author', true ) as $key ) {
		unset( $meta_parts[ $key ] );
	}
	return $meta_parts;
} );Code language: PHP (php)

Example: Add Comment Count to footer_meta

This adds a new section to display the comment count:

add_filter( 'amp_post_article_footer_meta', function ( $meta_parts ) {
	$meta_parts[] = 'xyz-meta-comment-count';
	return $meta_parts;
} );

add_filter( 'amp_post_template_file', function ( $file, $type, $post ) {
	if ( 'xyz-meta-comment-count' === $type ) {
		$file = dirname( __FILE__ ) . '/templates/xyz-meta-comment-count.php';
	}
	return $file;
}, 10, 3 );Code language: PHP (php)

Then, in templates/xyz-meta-comment-count.php:

<li>
	<?php printf( _n( '%d comment', '%d comments', $this->get( 'post' )->comment_count, 'xyz-text-domain' ) ); ?>
</li>Code language: HTML, XML (xml)

Custom CSS #

Rule Additions

If you want to append to the existing CSS rules (e.g. styles for a custom embed handler), you can use the amp_post_template_css action:

add_action( 'amp_post_template_css', function ( $amp_template ) {
	// only CSS here please...
	?>
	.amp-wp-byline amp-img {
		border-radius: 0; /* we don't want round avatars! */
	}
	.my-custom-class {
		color: blue;
	}
	<?php
} );Code language: PHP (php)

Completely Override CSS

If you’d prefer to use your own styles, you can either:

• Create a folder in your theme called amp and add a file called style.php with your custom CSS.
• Specify a custom template using the amp_post_template_file filter for 'style' === $type. See the “Override” examples in the “Meta” section for examples.

Note: the file should only include CSS, not the <style> opening and closing tag.

Head and Footer #

If you want to add stuff to the head or footer of the default AMP template, use the amp_post_template_head and amp_post_template_footer actions.

add_action( 'amp_post_template_footer', function ( $amp_template ) {
	$post_id = $amp_template->get( 'post_id' );
	?>
	<amp-pixel src="https://example.com/hi.gif?x=RANDOM"></amp-pixel>
	<?php
} );Code language: PHP (php)

AMP Endpoint #

If you don’t want to use the default /amp endpoint, use the amp_query_var filter to change it to anything else.

add_filter( 'amp_query_var' , function ( $amp_endpoint ) {
	return 'foo';
} );Code language: PHP (php)

Custom Template #

If you want complete control over the look and feel of your AMP content, you can override the default template using the amp_post_template_file filter and pass it the path to a custom template:

add_filter( 'amp_post_template_file', function ( $file, $type ) {
	if ( 'single' === $type ) {
		$file = dirname( __FILE__ ) . '/templates/my-amp-template.php';
	}
	return $file;
}, 10, 3 );Code language: PHP (php)

Note: there are some requirements for a custom template:

You must trigger the amp_post_template_head action in the <head> section:

do_action( 'amp_post_template_head', $this );Code language: JavaScript (javascript)

You must trigger the amp_post_template_footer action right before the </body> tag:

do_action( 'amp_post_template_footer', $this );
Code language: JavaScript (javascript)

Within your amp-custom style tags, you must trigger the amp_post_template_css action:

do_action( 'amp_post_template_css', $this );Code language: JavaScript (javascript)

You must include all required mark-up that isn’t already output via the amp_post_template_head action.

Custom Post Type Support #

By default, the plugin only creates AMP content for posts and (as of 0.6) pages. Also as of 0.6, you can enable AMP support for other post types via the AMP settings admin screen. Just enable the checkbox with each post type which is able to be served as AMP.

You can also add support for other post types by adding add_post_type_support() calls in PHP for the desired post types. For example, assuming our post type is xyz-review you can add AMP support by adding the following to a theme or plugin:

add_action( 'amp_init', function () {
	add_post_type_support( 'xyz-review', amp_get_slug() );
} );Code language: JavaScript (javascript)

You’ll need to flush your rewrite rules after this. You can do this by accessing the Permalinks admin screen or via running wp rewrite flush in WP-CLI.

If you want to add post type support but have AMP be disabled by default, you can use the following plugin code:

add_filter( 'amp_post_status_default_enabled', function ( $default, $post ) {
	if ( 'xyz-review' === $post->post_type ) {
		$default = false;
	}
	return $default;
}, 10, 2 );Code language: PHP (php)

If you want a custom template for your post type:

add_filter( 'amp_post_template_file', function ( $file, $type, $post ) {
	if ( 'single' === $type && 'xyz-review' === $post->post_type ) {
		$file = dirname( __FILE__ ) . '/templates/my-amp-review-template.php';
	}
	return $file;
}, 10, 3 );Code language: PHP (php)

We may provide better ways to handle this in the future.