check_comment( string $author, string $email, string $url, string $comment, string $user_ip, string $user_agent, string $comment_type ): bool

43function check_comment( $author, $email, $url, $comment, $user_ip, $user_agent, $comment_type ) {44	global $wpdb;45 46	// If manual moderation is enabled, skip all checks and return false.47	if ( '1' === get_option( 'comment_moderation' ) ) {48		return false;49	}50 51	/** This filter is documented in wp-includes/comment-template.php */52	$comment = apply_filters( 'comment_text', $comment, null, array() );53 54	// Check for the number of external links if a max allowed number is set.55	$max_links = get_option( 'comment_max_links' );56	if ( $max_links ) {57		$num_links = preg_match_all( '/<a [^>]*href/i', $comment, $out );58 59		/**60		 * Filters the number of links found in a comment.61		 *62		 * @since 3.0.063		 * @since 4.7.0 Added the `$comment` parameter.64		 *65		 * @param int    $num_links The number of links found.66		 * @param string $url       Comment author's URL. Included in allowed links total.67		 * @param string $comment   Content of the comment.68		 */69		$num_links = apply_filters( 'comment_max_links_url', $num_links, $url, $comment );70 71		/*72		 * If the number of links in the comment exceeds the allowed amount,73		 * fail the check by returning false.74		 */75		if ( $num_links >= $max_links ) {76			return false;77		}78	}79 80	$mod_keys = trim( get_option( 'moderation_keys' ) );81 82	// If moderation 'keys' (keywords) are set, process them.83	if ( ! empty( $mod_keys ) ) {84		$words = explode( "\n", $mod_keys );85 86		foreach ( (array) $words as $word ) {87			$word = trim( $word );88 89			// Skip empty lines.90			if ( empty( $word ) ) {91				continue;92			}93 94			/*95			 * Do some escaping magic so that '#' (number of) characters in the spam96			 * words don't break things:97			 */98			$word = preg_quote( $word, '#' );99 100			/*101			 * Check the comment fields for moderation keywords. If any are found,102			 * fail the check for the given field by returning false.103			 */104			$pattern = "#$word#iu";105			if ( preg_match( $pattern, $author ) ) {106				return false;107			}108			if ( preg_match( $pattern, $email ) ) {109				return false;110			}111			if ( preg_match( $pattern, $url ) ) {112				return false;113			}114			if ( preg_match( $pattern, $comment ) ) {115				return false;116			}117			if ( preg_match( $pattern, $user_ip ) ) {118				return false;119			}120			if ( preg_match( $pattern, $user_agent ) ) {121				return false;122			}