]*>.*?#is'; protected const BLOCK_BOUNDARY_PATTERN = '#]*>|#i'; protected const SENTENCE_BOUNDARY_PATTERN = '/(?<=[.!?])\s+|(?<=[.!?]["\')\]])\s+|(?<=[。！？])/u'; protected const SENTENCE_END_PATTERN = '/\p{L}.*[.!?。！？]["\')\]]?$/u'; protected const DECODED_MARKUP_PATTERN = '#]+))*\s*/?>#i'; protected const WHITESPACE_PATTERN = '/[\s\p{Z}]+/u'; protected const LEGACY_PUNCTUATION_ENCODING = 'Windows-1252'; protected const UTF8_SEQUENCE_PATTERN = '/ [\x00-\x7F] | [\xC2-\xDF][\x80-\xBF] | \xE0[\xA0-\xBF][\x80-\xBF] | [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2} | \xED[\x80-\x9F][\x80-\xBF] | \xF0[\x90-\xBF][\x80-\xBF]{2} | [\xF1-\xF3][\x80-\xBF]{3} | \xF4[\x80-\x8F][\x80-\xBF]{2} | (?.) /xs'; public function get_summary( WP_Post $post ): string { $excerpt = $this->to_plain_text( $post->post_excerpt ); if ( $excerpt !== '' ) { return $excerpt; } return $this->get_content_summary( $post ); } protected function get_content_summary( WP_Post $post ): string { $body_html = $this->replace_or_keep( self::HEADING_PATTERN, '', do_blocks( $post->post_content ) ); foreach ( $this->split_into_text_blocks( $body_html ) as $text_block ) { $summary = $this->take_leading_sentences( $text_block ); if ( $summary !== '' ) { return $summary; } } return ''; } protected function take_leading_sentences( string $text ): string { $sentences = preg_split( self::SENTENCE_BOUNDARY_PATTERN, $text, -1, PREG_SPLIT_OFFSET_CAPTURE ); if ( ! is_array( $sentences ) ) { return ''; } $summary = ''; foreach ( $sentences as $sentence ) { list( $sentence_text, $sentence_offset ) = $sentence; if ( ! $this->is_complete_sentence( $sentence_text ) ) { break; } $candidate = trim( substr( $text, 0, $sentence_offset + strlen( $sentence_text ) ) ); if ( $this->has_enough_text( $summary ) && $this->character_count( $candidate ) > self::TARGET_LENGTH ) { break; } $summary = $candidate; } return $this->has_enough_text( $summary ) ? $summary : ''; } protected function is_complete_sentence( string $sentence ): bool { return (bool) preg_match( self::SENTENCE_END_PATTERN, $sentence ); } protected function has_enough_text( string $summary ): bool { if ( $this->character_count( $summary ) >= self::MINIMUM_CHARACTERS ) { return true; } $words = preg_split( self::WHITESPACE_PATTERN, $summary, -1, PREG_SPLIT_NO_EMPTY ); if ( ! is_array( $words ) ) { return false; } return count( $words ) >= self::MINIMUM_WORDS; } /** * Core's mb_strlen() polyfill counts bytes unless it is given an encoding. */ protected function character_count( string $text ): int { return mb_strlen( $text, 'UTF-8' ); } protected function to_plain_text( string $html ): string { return implode( ' ', $this->split_into_text_blocks( $html ) ); } protected function split_into_text_blocks( string $html ): array { $chunks = preg_split( self::BLOCK_BOUNDARY_PATTERN, $html ); if ( ! is_array( $chunks ) ) { return array(); } $text_blocks = array(); foreach ( $chunks as $chunk ) { $text = $this->strip_markup( $chunk ); if ( $text !== '' ) { $text_blocks[] = $text; } } return $text_blocks; } protected function strip_markup( string $html ): string { $text = $this->to_valid_utf8( $html ); $decoded = html_entity_decode( wp_strip_all_tags( strip_shortcodes( $text ) ), ENT_QUOTES | ENT_HTML5, 'UTF-8' ); $plain = $this->replace_or_keep( self::DECODED_MARKUP_PATTERN, '', $decoded ); return trim( $this->replace_or_keep( self::WHITESPACE_PATTERN, ' ', $plain ) ); } protected function to_valid_utf8( string $text ): string { if ( $this->is_valid_utf8( $text ) ) { return $text; } if ( function_exists( 'mb_convert_encoding' ) ) { $repaired = $this->repair_invalid_bytes( $text ); if ( $repaired !== '' && $this->is_valid_utf8( $repaired ) ) { return $repaired; } } return wp_check_invalid_utf8( $text, true ); } /** * Only the invalid bytes are converted; converting the whole string would re-encode * punctuation that is already correct. */ protected function repair_invalid_bytes( string $text ): string { $repaired = preg_replace_callback( self::UTF8_SEQUENCE_PATTERN, static function ( array $matches ): string { if ( ! isset( $matches['invalid'] ) ) { return $matches[0]; } return (string) mb_convert_encoding( $matches['invalid'], 'UTF-8', self::LEGACY_PUNCTUATION_ENCODING ); }, $text ); return $repaired ?? $text; } /** * wp_check_invalid_utf8() answers on the site's blog_charset rather than on the bytes, * and wp_is_valid_utf8() only exists from WordPress 6.9 while this plugin supports 5.5. */ protected function is_valid_utf8( string $text ): bool { return preg_match( '//u', $text ) === 1; } protected function replace_or_keep( string $pattern, string $replacement, string $subject ): string { return preg_replace( $pattern, $replacement, $subject ) ?? $subject; } }