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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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use ABlocks\Helper; |
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|
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/** |
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* Performance Suite — image loading optimizations for aBlocks blocks. |
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* |
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* Adds `loading="lazy"` + `decoding="async"` to images, while keeping the first |
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* N images eager with `fetchpriority="high"` so the LCP image isn't deferred. |
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* |
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* Opt-in via `perf_lazy_images`. Operates on rendered block HTML (scoped to |
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* aBlocks blocks) so no per-block markup changes are needed. |
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*/ |
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class ImageOptimizer { |
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|
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private $image_index = 0; |
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private $eager_count = 1; |
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|
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public static function init() { |
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if ( is_admin() ) { |
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return; |
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} |
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$enabled = (bool) apply_filters( |
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'ablocks/perf/perf_lazy_images', |
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(bool) Helper::get_settings( 'perf_lazy_images', true ) |
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); |
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if ( ! $enabled ) { |
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return; |
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} |
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$self = new self(); |
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$self->eager_count = (int) apply_filters( |
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'ablocks/perf/lcp_eager_count', |
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(int) Helper::get_settings( 'perf_lcp_eager_count', 1 ) |
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); |
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add_filter( 'render_block', [ $self, 'process' ], 20, 2 ); |
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} |
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|
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public function process( $content, $block ) { |
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if ( empty( $block['blockName'] ) || false === strpos( $block['blockName'], 'ablocks' ) ) { |
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return $content; |
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} |
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if ( false === strpos( $content, '<img' ) ) { |
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return $content; |
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} |
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|
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return preg_replace_callback( |
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'/<img\b(?![^>]*\bloading=)[^>]*>/i', |
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[ $this, 'rewrite_img' ], |
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$content |
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); |
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} |
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|
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private function rewrite_img( $matches ) { |
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$tag = $matches[0]; |
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$this->image_index++; |
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|
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if ( $this->image_index <= $this->eager_count ) { |
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// Likely-LCP images: load eagerly with high priority. |
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$attrs = ' loading="eager" fetchpriority="high"'; |
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} else { |
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$attrs = ' loading="lazy"'; |
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} |
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|
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if ( false === stripos( $tag, 'decoding=' ) ) { |
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$attrs .= ' decoding="async"'; |
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} |
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|
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return preg_replace( '/^<img\b/', '<img' . $attrs, $tag, 1 ); |
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} |
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} |
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|
