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<?php |
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namespace ABlocks\Performance; |
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|
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if ( ! defined( 'ABSPATH' ) ) { |
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exit; |
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} |
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|
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/** |
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* The shared mechanism for stopping a <script> tag from executing, and letting |
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* something on the client release it later. |
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* |
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* Two features need exactly this. `DelayJs` holds aBlocks' own scripts back |
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* until the first user interaction; the cookie-consent addon holds third-party |
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* tags back until consent for their category is granted. Both do the same three |
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* things — decide whether a tag is in scope, rewrite its type so the browser |
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* parses but does not run it, and release it later — so the rewriting lives |
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* here once rather than as two independent regexes over every script on the |
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* page. |
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* |
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* The rewrite is deliberately textual. `script_loader_tag` hands over a string, |
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* and the consent addon's second layer works on already-rendered markup, so a |
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* DOM-based rewrite is not available in either caller. |
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*/ |
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class ScriptGate { |
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|
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/** |
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* Marker type written into the tag, e.g. `ablocks/delayed` or `text/plain`. |
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* |
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* @var string |
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*/ |
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private $type; |
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|
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/** |
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* `( $handle, $src, $tag ) => bool` — whether this tag is in scope. |
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* |
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* @var callable |
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*/ |
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private $in_scope; |
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|
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/** |
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* `( $handle, $src ) => array` — extra attributes to write onto the tag. |
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* |
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* @var callable|null |
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*/ |
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private $attributes; |
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|
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/** |
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* Whether to move `src` out of the way as well as changing the type. |
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* |
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* @var bool |
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*/ |
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private $move_src; |
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|
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public function __construct( $type, callable $in_scope, $attributes = null, $move_src = false ) { |
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$this->type = $type; |
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$this->in_scope = $in_scope; |
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$this->attributes = $attributes; |
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$this->move_src = (bool) $move_src; |
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} |
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|
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/** |
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* Start filtering enqueued script tags. |
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* |
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* @param int $priority Filter priority. |
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*/ |
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public function hook( $priority = 20 ) { |
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add_filter( 'script_loader_tag', [ $this, 'filter_tag' ], $priority, 3 ); |
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} |
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|
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/** |
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* @param string $tag Rendered script tag. |
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* @param string $handle Script handle. |
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* @param string $src Script source. |
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* @return string |
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*/ |
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public function filter_tag( $tag, $handle, $src ) { |
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if ( ! call_user_func( $this->in_scope, $handle, $src, $tag ) ) { |
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return $tag; |
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} |
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$attrs = $this->attributes ? (array) call_user_func( $this->attributes, $handle, $src ) : []; |
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return self::rewrite_tag( $tag, $this->type, $attrs, $this->move_src ); |
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} |
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|
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/** |
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* Rewrite one script tag so the browser will not execute it. |
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* |
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* A `<script>` whose type is not a JavaScript MIME type is parsed as a data |
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* block: it does not run, and — this is the part that matters for consent — |
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* a `src` on it is never fetched either, so no request reaches the third |
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* party before the visitor has decided. |
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* |
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* @param string $tag The full `<script …>` opening tag, or a whole tag pair. |
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* @param string $type Marker type to write. |
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* @param array $attrs Extra attributes, name => value. |
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* @param bool $move_src Whether to rename `src` to `data-ablocks-src`. |
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* @return string |
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*/ |
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public static function rewrite_tag( $tag, $type, array $attrs = [], $move_src = false ) { |
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if ( $move_src ) { |
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$tag = preg_replace( '/\ssrc=/', ' data-ablocks-src=', $tag, 1 ); |
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} |
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|
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$extra = ''; |
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foreach ( $attrs as $name => $value ) { |
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$extra .= sprintf( '%s="%s" ', esc_attr( $name ), esc_attr( $value ) ); |
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} |
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|
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// An existing type is preserved so the release step can restore it — |
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// `type="module"` is not interchangeable with a classic script. |
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if ( preg_match( '/\stype=["\']([^"\']*)["\']/i', $tag, $found ) ) { |
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$extra .= sprintf( 'data-ablocks-type="%s" ', esc_attr( $found[1] ) ); |
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$tag = preg_replace( '/\stype=["\'][^"\']*["\']/i', '', $tag, 1 ); |
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} |
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|
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return preg_replace( |
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'/^<script\s/', |
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sprintf( '<script type="%s" %s', esc_attr( $type ), $extra ), |
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$tag, |
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1 |
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); |
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} |
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|
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/** |
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* Whether a tag has already been gated by either feature. |
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* |
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* @param string $tag Script tag. |
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* @return bool |
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*/ |
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public static function is_gated( $tag ) { |
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return (bool) preg_match( '/\stype=["\'](?:text\/plain|ablocks\/[a-z-]+)["\']/i', $tag ); |
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} |
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} |
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|
