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<?php |
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/** |
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* Cdn_Rewriter — rewrites local-origin asset URLs to a user-supplied |
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* CDN hostname (BunnyCDN, KeyCDN, Cloudflare R2 pull-zone, etc.). |
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* |
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* Assumes pull-zone CDN (CDN fetches from origin on demand); we never |
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* upload anything. The user sets `cdn_url` to e.g. `cdn.example.com` |
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* and we rewrite asset URLs from `https://example.com/wp-content/…` |
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* to `https://cdn.example.com/wp-content/…`. |
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* |
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* Strategy: same buffer-pass approach as Lazy_Loader — regex over |
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* specific tag attributes is ~10× faster than a full DOMDocument round |
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* trip, and CDN rewriting is purely a string substitution on URLs that |
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* point at the site origin. Out-of-origin URLs are left alone. |
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* |
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* Handled attributes: src, href, srcset, data-src, data-srcset, poster. |
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* Honors extension whitelist + glob exclude patterns (reuses |
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* Glob_Matcher so `*.pdf` / `/cart/*` work the same as elsewhere). |
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* |
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* @package XSpeed |
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*/ |
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|
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declare(strict_types=1); |
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|
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namespace XSpeed; |
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|
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defined( 'ABSPATH' ) || exit; |
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|
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final class Cdn_Rewriter { |
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|
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/** @var array|null */ |
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private static $opts = null; |
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/** @var string|null */ |
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private static $home_host = null; |
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/** @var string */ |
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private static $home_scheme = 'https'; |
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|
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public const DEFAULT_EXTENSIONS = array( |
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'jpg', 'jpeg', 'png', 'gif', 'webp', 'avif', 'svg', 'ico', |
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'woff', 'woff2', 'ttf', 'otf', 'eot', |
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'css', 'js', |
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'mp4', 'webm', 'mp3', 'ogg', |
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); |
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|
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public static function reset_state(): void { |
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self::$opts = null; |
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self::$home_host = null; |
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self::$home_scheme = 'https'; |
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} |
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|
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/** |
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* Top-level HTML transform. Returns input unchanged if disabled or |
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* cdn_url is empty. |
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*/ |
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public static function process_html( string $html ): string { |
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if ( '' === $html ) { |
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return $html; |
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} |
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$opts = self::opts(); |
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if ( empty( $opts['enabled'] ) || empty( $opts['cdn_url'] ) ) { |
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return $html; |
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} |
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self::prime_origin(); |
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|
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// Rewrite src, href, poster, data-src. |
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$html = preg_replace_callback( |
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'#\b(src|href|poster|data-src)\s*=\s*([\'"])([^\'"]+)\2#i', |
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static function ( $m ) use ( $opts ) { |
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$rewritten = self::rewrite_url( $m[3], $opts ); |
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return $m[1] . '=' . $m[2] . $rewritten . $m[2]; |
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}, |
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$html |
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); |
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|
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// Rewrite srcset / data-srcset (comma-separated `url 1x, url 2x`). |
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$html = preg_replace_callback( |
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'#\b(srcset|data-srcset)\s*=\s*([\'"])([^\'"]+)\2#i', |
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static function ( $m ) use ( $opts ) { |
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$rewritten = self::rewrite_srcset( $m[3], $opts ); |
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return $m[1] . '=' . $m[2] . $rewritten . $m[2]; |
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}, |
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$html |
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); |
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|
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return $html; |
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} |
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|
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/** |
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* Public for tests + REST validation. Returns the rewritten URL or |
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* the input unchanged. |
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*/ |
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public static function rewrite_url( string $url, array $opts ): string { |
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$url = trim( $url ); |
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if ( '' === $url ) { |
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return $url; |
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} |
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if ( null === self::$home_host ) { |
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self::prime_origin(); |
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} |
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// Skip data:, mailto:, tel:, javascript:, fragments, blob:. |
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if ( preg_match( '#^(data|mailto|tel|javascript|blob|about):#i', $url ) ) { |
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return $url; |
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} |
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if ( '#' === substr( $url, 0, 1 ) ) { |
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return $url; |
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} |
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|
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$abs = self::absolutize( $url ); |
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if ( null === $abs ) { |
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return $url; |
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} |
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|
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// Must be same origin. |
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$parts = wp_parse_url( $abs ); |
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if ( ! is_array( $parts ) || empty( $parts['host'] ) ) { |
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return $url; |
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} |
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if ( strtolower( $parts['host'] ) !== self::$home_host ) { |
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return $url; |
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} |
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|
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$path = (string) ( $parts['path'] ?? '' ); |
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if ( '' === $path ) { |
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return $url; |
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} |
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|
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// Extension whitelist. |
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$included = isset( $opts['included_extensions'] ) && is_array( $opts['included_extensions'] ) |
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? $opts['included_extensions'] |
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: self::DEFAULT_EXTENSIONS; |
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$ext = strtolower( pathinfo( $path, PATHINFO_EXTENSION ) ); |
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if ( '' === $ext || ! in_array( $ext, array_map( 'strtolower', $included ), true ) ) { |
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return $url; |
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} |
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|
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// Excluded path globs (reuse Glob_Matcher for *.pdf, /cart/*). |
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$excluded = isset( $opts['excluded_patterns'] ) && is_array( $opts['excluded_patterns'] ) |
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? $opts['excluded_patterns'] |
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: array(); |
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foreach ( $excluded as $pattern ) { |
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if ( '' === $pattern ) { |
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continue; |
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} |
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if ( class_exists( '\\XSpeed\\Glob_Matcher' ) && Glob_Matcher::matches( $pattern, $path ) ) { |
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return $url; |
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} |
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} |
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|
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$cdn_host = self::normalize_host( (string) $opts['cdn_url'] ); |
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if ( '' === $cdn_host ) { |
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return $url; |
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} |
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|
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$query = isset( $parts['query'] ) ? '?' . $parts['query'] : ''; |
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$fragment = isset( $parts['fragment'] ) ? '#' . $parts['fragment'] : ''; |
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|
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return self::$home_scheme . '://' . $cdn_host . $path . $query . $fragment; |
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} |
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|
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/** |
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* Rewrite each candidate URL inside an srcset descriptor list. |
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*/ |
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public static function rewrite_srcset( string $srcset, array $opts ): string { |
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$parts = preg_split( '#\s*,\s*#', trim( $srcset ) ); |
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if ( ! is_array( $parts ) ) { |
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return $srcset; |
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} |
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$out = array(); |
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foreach ( $parts as $candidate ) { |
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$candidate = trim( $candidate ); |
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if ( '' === $candidate ) { |
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continue; |
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} |
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// `<url> <descriptor>` — descriptor optional (1x, 2x, 800w). |
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$split = preg_split( '#\s+#', $candidate, 2 ); |
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$url = $split[0]; |
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$descr = isset( $split[1] ) ? ' ' . $split[1] : ''; |
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$rewritten = self::rewrite_url( $url, $opts ); |
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$out[] = $rewritten . $descr; |
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} |
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return implode( ', ', $out ); |
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} |
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|
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/** |
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* Convert relative/scheme-relative URLs to absolute against the site |
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* origin. Returns null if we can't make sense of it. |
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*/ |
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private static function absolutize( string $url ): ?string { |
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if ( preg_match( '#^https?://#i', $url ) ) { |
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return $url; |
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} |
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if ( 0 === strpos( $url, '//' ) ) { |
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return self::$home_scheme . ':' . $url; |
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} |
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if ( 0 === strpos( $url, '/' ) ) { |
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return self::$home_scheme . '://' . self::$home_host . $url; |
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} |
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// Bare relative paths like `images/x.png` — these would need a |
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// base URL to resolve. The DOM rendering picked one already; we |
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// can't reliably guess. Leave alone. |
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return null; |
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} |
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|
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/** |
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* Strip scheme + trailing slash from a user-entered CDN URL so the |
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* stored value is just a host (cdn.example.com). Tolerant of |
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* `https://cdn.example.com/`, `//cdn.example.com`, or bare host. |
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*/ |
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public static function normalize_host( string $value ): string { |
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$value = trim( $value ); |
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if ( '' === $value ) { |
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return ''; |
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} |
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$value = preg_replace( '#^https?://#i', '', $value ); |
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$value = preg_replace( '#^//#', '', $value ); |
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$value = rtrim( $value, '/' ); |
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return strtolower( $value ); |
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} |
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|
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private static function prime_origin(): void { |
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$home = function_exists( 'home_url' ) ? home_url() : ''; |
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$p = wp_parse_url( $home ); |
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if ( is_array( $p ) && ! empty( $p['host'] ) ) { |
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self::$home_host = strtolower( $p['host'] ); |
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self::$home_scheme = isset( $p['scheme'] ) ? strtolower( $p['scheme'] ) : 'https'; |
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} |
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} |
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|
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private static function opts(): array { |
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if ( null === self::$opts ) { |
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self::$opts = function_exists( 'get_option' ) |
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? (array) get_option( 'xspeed_module_cdn', array() ) |
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: array(); |
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} |
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return self::$opts; |
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} |
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} |
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|
