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<?php |
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/** |
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* Remote fetcher for stylesheets and font binaries. |
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* |
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* @package EasyFonts |
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*/ |
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|
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namespace EasyFonts\Fonts; |
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|
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defined( 'ABSPATH' ) || exit; |
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|
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/** |
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* Downloads Google/Bunny CSS and font files. |
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*/ |
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class Downloader { |
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|
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/** |
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* Whether remote font-binary downloads are allowed in the current request. |
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* Set to false during a normal visitor render (so the page is never blocked |
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* by synchronous downloads); true during admin/CLI/warm (probe) requests. |
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* |
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* @var bool |
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*/ |
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private static bool $allow_fonts = true; |
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|
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/** |
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* Allow/disallow remote font-binary downloads for this request. |
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* |
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* @param bool $allow Allowed? |
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* @return void |
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*/ |
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public static function set_allow_fonts( bool $allow ): void { |
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self::$allow_fonts = $allow; |
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} |
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|
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/** |
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* Are remote font-binary downloads currently allowed? |
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* |
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* @return bool |
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*/ |
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public static function fonts_allowed(): bool { |
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return self::$allow_fonts; |
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} |
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|
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/** |
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* Modern desktop UA so the API returns woff2. |
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*/ |
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const UA_WOFF2 = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:124.0) Gecko/20100101 Firefox/124.0'; |
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|
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/** |
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* Old UA that makes the API return TTF (used for metric extraction only). |
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*/ |
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const UA_TTF = 'Mozilla/5.0 (Windows NT 6.1; rv:27.0) Gecko/20100101 Firefox/27.0'; |
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|
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/** |
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* Content-Type => extension. |
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*/ |
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const MIME = array( |
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'font/woff2' => 'woff2', |
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'application/font-woff2' => 'woff2', |
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'font/woff' => 'woff', |
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'application/font-woff' => 'woff', |
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'font/ttf' => 'ttf', |
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'application/x-font-ttf' => 'ttf', |
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'font/sfnt' => 'ttf', |
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'application/font-sfnt' => 'ttf', |
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'font/otf' => 'otf', |
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'application/x-font-opentype' => 'otf', |
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'application/vnd.ms-fontobject' => 'eot', |
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); |
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|
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/** |
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* SSRF guard for stylesheet fetches. Unlike font binaries (locked to a |
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* provider allow-list), CSS may legitimately be fetched from ANY public host |
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* — that's how fonts hidden in third-party/CDN stylesheets are detected. So |
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* here we don't allow-list hosts; we deny-list internal targets: non-HTTP(S) |
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* schemes and any host that resolves to a private, reserved, loopback or |
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* link-local address (e.g. 127.0.0.1, 10/8, 192.168/16, 169.254.169.254). |
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* This blocks pointing the fetcher at internal services without affecting |
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* any real public stylesheet. Filterable for intranet installs. |
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* |
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* @param string $url Absolute URL. |
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* @return bool |
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*/ |
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public static function is_public_url( string $url ): bool { |
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/** |
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* Allow fetching from private/internal hosts (intranet installs). |
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* |
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* @param bool $allow Default false. |
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* @param string $url The URL under test. |
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*/ |
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if ( apply_filters( 'easyfonts_allow_private_fetch', false, $url ) ) { |
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return true; |
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} |
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|
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$parts = wp_parse_url( $url ); |
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$scheme = strtolower( (string) ( $parts['scheme'] ?? '' ) ); |
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$host = (string) ( $parts['host'] ?? '' ); |
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|
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if ( ( 'http' !== $scheme && 'https' !== $scheme ) || '' === $host ) { |
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return false; |
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} |
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|
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// Collect candidate IPs: literal host, or resolved A/AAAA records. |
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$ips = array(); |
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|
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if ( filter_var( $host, FILTER_VALIDATE_IP ) ) { |
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$ips[] = $host; |
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} else { |
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$v4 = gethostbynamel( $host ); |
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|
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if ( is_array( $v4 ) ) { |
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$ips = array_merge( $ips, $v4 ); |
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} |
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|
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if ( function_exists( 'dns_get_record' ) ) { |
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$v6 = @dns_get_record( $host, DNS_AAAA ); // phpcs:ignore WordPress.PHP.NoSilencedErrors |
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|
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if ( is_array( $v6 ) ) { |
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foreach ( $v6 as $rec ) { |
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if ( ! empty( $rec['ipv6'] ) ) { |
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$ips[] = $rec['ipv6']; |
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} |
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} |
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} |
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} |
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} |
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|
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// Couldn't resolve → not a known-internal target; let the HTTP layer |
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// deal with it (it simply won't connect). |
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if ( empty( $ips ) ) { |
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return true; |
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} |
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|
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foreach ( $ips as $ip ) { |
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if ( ! filter_var( $ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE ) ) { |
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return false; // private / reserved / loopback / link-local. |
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} |
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} |
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|
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return true; |
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} |
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|
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/** |
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* Fetch CSS text from a font-provider URL. |
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* |
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* @param string $url Stylesheet URL. |
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* @return string|null |
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*/ |
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public function fetch_css( string $url ): ?string { |
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$url = \EasyFonts\Detect\Providers::normalize_url( $url ); |
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|
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// Cache the fetched CSS so font detection doesn't hit the network on every |
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// page render. Keyed by URL + cache-buster, so any settings/font change |
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// (which bumps the buster) transparently refreshes it. |
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$cache_key = 'easyfonts_css_' . md5( $url . '|' . \EasyFonts\Settings::buster() ); |
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$cached = get_transient( $cache_key ); |
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|
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if ( is_string( $cached ) && '' !== $cached ) { |
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return $cached; |
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} |
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|
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// SSRF guard: never fetch a stylesheet from an internal/private address. |
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if ( ! self::is_public_url( $url ) ) { |
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return null; |
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} |
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|
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$response = wp_remote_get( |
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$url, |
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array( |
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'timeout' => 10, |
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'user-agent' => apply_filters( 'easyfonts_css_user_agent', self::UA_WOFF2 ), |
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) |
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); |
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|
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if ( is_wp_error( $response ) || 200 !== (int) wp_remote_retrieve_response_code( $response ) ) { |
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return null; |
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} |
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|
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$body = wp_remote_retrieve_body( $response ); |
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|
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if ( '' === $body ) { |
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return null; |
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} |
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|
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set_transient( $cache_key, $body, 7 * DAY_IN_SECONDS ); |
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|
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return $body; |
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} |
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|
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/** |
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* Download a font binary into the cache and return [filename, ext, size]. |
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* |
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* @param string $url Font file URL. |
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* @param string $basename Cache basename (without extension). |
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* @param Storage $storage Storage. |
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* @return array{file:string,ext:string,size:int}|null |
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*/ |
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public function fetch_font( string $url, string $basename, Storage $storage ): ?array { |
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// Never download a font binary during a normal visitor page render — that |
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// is what could stall the request and white-screen the site. On the render |
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// path we serve only already-cached fonts; missing ones are fetched by a |
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// background warm (probe) request. Admin/CLI/warm requests set this true. |
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if ( ! self::$allow_fonts ) { |
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return null; |
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} |
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|
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$url = \EasyFonts\Detect\Providers::normalize_url( $url ); |
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|
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// SSRF guard: only fetch font binaries from recognised provider hosts |
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// (or the site's own origin). A crafted @font-face can otherwise point |
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// src at an internal address; this blocks that without affecting any |
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// legitimate Google/Bunny/wp.com font. Filterable for niche providers. |
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if ( ! self::host_allowed( $url ) ) { |
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return null; |
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} |
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|
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$response = wp_remote_get( |
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$url, |
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array( |
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'timeout' => 10, |
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'user-agent' => self::UA_WOFF2, |
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) |
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); |
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|
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if ( is_wp_error( $response ) ) { |
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return null; |
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} |
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|
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$code = (int) wp_remote_retrieve_response_code( $response ); |
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|
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if ( $code < 200 || $code >= 300 ) { |
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return null; |
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} |
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|
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$body = wp_remote_retrieve_body( $response ); |
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|
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if ( '' === $body ) { |
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return null; |
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} |
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|
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$ct = strtolower( trim( explode( ';', (string) wp_remote_retrieve_header( $response, 'content-type' ) )[0] ) ); |
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$ext = self::MIME[ $ct ] ?? $this->ext_from_url( $url ); |
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|
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$filename = $basename . '.' . $ext; |
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|
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if ( ! $storage->write( $filename, $body ) ) { |
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return null; |
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} |
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|
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return array( |
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'file' => $filename, |
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'ext' => $ext, |
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'size' => strlen( $body ), |
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); |
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} |
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|
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/** |
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* Fetch the raw bytes of a TTF copy of a Google Fonts family for metrics. |
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* Returns the binary, never writes it to disk. |
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* |
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* @param string $css_url Original CSS URL. |
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* @return string|null |
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*/ |
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public function fetch_ttf_bytes( string $css_url ): ?string { |
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$response = wp_remote_get( |
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$css_url, |
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array( |
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'timeout' => 20, |
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'user-agent' => self::UA_TTF, |
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) |
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); |
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|
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if ( is_wp_error( $response ) || 200 !== (int) wp_remote_retrieve_response_code( $response ) ) { |
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return null; |
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} |
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|
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$css = wp_remote_retrieve_body( $response ); |
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|
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if ( ! preg_match( '/src\s*:\s*[^;]*?url\(\s*[\'"]?([^\'")]+\.(?:ttf|otf))[\'"]?\s*\)/i', $css, $m ) ) { |
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return null; |
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} |
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|
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// The font URL comes out of fetched CSS — guard it the same way. |
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if ( ! self::is_public_url( $m[1] ) ) { |
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return null; |
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} |
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|
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$font = wp_remote_get( $m[1], array( 'timeout' => 20 ) ); |
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|
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if ( is_wp_error( $font ) || 200 !== (int) wp_remote_retrieve_response_code( $font ) ) { |
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return null; |
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} |
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|
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$bytes = wp_remote_retrieve_body( $font ); |
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|
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return '' === $bytes ? null : $bytes; |
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} |
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|
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/** |
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* Fetch TTF bytes for a specific Google family/weight purely for metric |
| 302 |
* extraction. Source-independent: we construct a css2 request from the |
| 303 |
* family name, so it works whether the font came from a <link>, @import, or |
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* an inline @font-face. Returns binary, never written to disk. |
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* |
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* @param string $family Family name (e.g. "Open Sans"). |
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* @param string $weight Representative numeric weight. |
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* @return string|null |
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*/ |
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public function fetch_family_ttf( string $family, string $weight = '400' ): ?string { |
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$weight = (string) absint( $weight ); |
| 312 |
|
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if ( '' === $weight || '0' === $weight ) { |
| 314 |
$weight = '400'; |
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} |
| 316 |
|
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$url = 'https://fonts.googleapis.com/css2?family=' |
| 318 |
. rawurlencode( $family ) . ':wght@' . $weight . '&display=swap'; |
| 319 |
$url = str_replace( '%20', '+', $url ); |
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|
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return $this->fetch_ttf_bytes( $url ); |
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} |
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|
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/** |
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* Is this URL host allowed for font-binary downloads? Provider font hosts |
| 326 |
* plus the site's own origin. Filterable via `easyfonts_font_src_hosts`. |
| 327 |
* |
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* @param string $url Absolute URL. |
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* @return bool |
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*/ |
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private static function host_allowed( string $url ): bool { |
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$host = strtolower( (string) wp_parse_url( $url, PHP_URL_HOST ) ); |
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|
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if ( '' === $host ) { |
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return false; |
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} |
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|
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$own = strtolower( (string) wp_parse_url( home_url(), PHP_URL_HOST ) ); |
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|
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/** |
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* Allowed host suffixes for downloading font binaries. |
| 342 |
* |
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* @param string[] $hosts |
| 344 |
*/ |
| 345 |
$allowed = apply_filters( |
| 346 |
'easyfonts_font_src_hosts', |
| 347 |
array( |
| 348 |
'fonts.gstatic.com', |
| 349 |
'fonts.googleapis.com', |
| 350 |
'fonts.bunny.net', |
| 351 |
'fonts.wp.com', |
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'fonts-api.wp.com', |
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's.w.org', |
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'i0.wp.com', |
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'i1.wp.com', |
| 356 |
'i2.wp.com', |
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) |
| 358 |
); |
| 359 |
|
| 360 |
if ( '' !== $own ) { |
| 361 |
$allowed[] = $own; |
| 362 |
} |
| 363 |
|
| 364 |
foreach ( $allowed as $candidate ) { |
| 365 |
$candidate = strtolower( trim( (string) $candidate ) ); |
| 366 |
|
| 367 |
if ( '' === $candidate ) { |
| 368 |
continue; |
| 369 |
} |
| 370 |
|
| 371 |
// Exact host or a subdomain of an allowed host. |
| 372 |
if ( $host === $candidate || substr( $host, -strlen( '.' . $candidate ) ) === '.' . $candidate ) { |
| 373 |
return true; |
| 374 |
} |
| 375 |
} |
| 376 |
|
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return false; |
| 378 |
} |
| 379 |
|
| 380 |
/** |
| 381 |
* Guess an extension from a URL path. |
| 382 |
* |
| 383 |
* @param string $url URL. |
| 384 |
* @return string |
| 385 |
*/ |
| 386 |
private function ext_from_url( string $url ): string { |
| 387 |
$ext = strtolower( (string) pathinfo( (string) wp_parse_url( $url, PHP_URL_PATH ), PATHINFO_EXTENSION ) ); |
| 388 |
|
| 389 |
return in_array( $ext, array( 'woff2', 'woff', 'ttf', 'otf', 'eot' ), true ) ? $ext : 'woff2'; |
| 390 |
} |
| 391 |
} |
| 392 |
|
