Automatic adding of AMP component scrips

[scottblackburn]

I was hoping for some advice regarding an issue we've had since upgrading to 0.7.1.

We use a custom template for our AMP implementation and manually add some amp-ad components into our header and footer. In addition to this, on longer posts we also add amp-ad components into the post content. Our current setup also manually adds the <script async custom-element="amp-ad" src="https://cdn.ampproject.org/v0/amp-ad-0.1.js"></script> into the head.

I understand that the plugin now automatically discovers the required AMP component scripts (#882, #885), but this only seems to work if the amp-ad components are added into post content, this detection doesn't seem to take into account any components added into the templates manually. This causes the following issues:

1. If the template contains a amp-ad and the post content also contains an amp-ad then the amp-ad script is added twice resulting in a validation warning.
2. If we no longer add in the amp-ad script directly to the template but also the post doesn't have any amp-ads appearing in the post content then the ad script doesn't load and the ads fail.

I understand that this issue could be caused by our implementation, but would it be possible to clarify how best to approach this situation?

[westonruter]

Sure thing. Here is the best way to do it to avoid duplication across plugins:

add_filter( 'amp_post_template_data', function( $data ) {
	$data['amp_component_scripts'] = array_merge(
		$data['amp_component_scripts'],
		array(
			'amp-ad' => 'https://cdn.ampproject.org/v0/amp-ad-latest.js',
		)
	);
	return $data;
} );

Ref: https://wordpress.org/support/topic/the-tag-amp-ad-extension-js-script-appears-more-than-once-in-the-document/#post-10262578