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

Checks whether a comment passes internal checks to be allowed to add.

Description

If manual comment moderation is set in the administration, then all checks, regardless of their type and substance, will fail and the function will return false.

If the number of links exceeds the amount in the administration, then the check fails. If any of the parameter contents contain any disallowed words, then the check fails.

If the comment author was approved before, then the comment is automatically approved.

If all checks pass, the function will return true.

Parameters

$authorstringrequired
Comment author name.
$emailstringrequired
Comment author email.
$urlstringrequired
Comment author URL.
$commentstringrequired
Content of the comment.
$user_ipstringrequired
Comment author IP address.
$user_agentstringrequired
Comment author User-Agent.
$comment_typestringrequired
Comment type, either user-submitted comment, trackback, or pingback.

Return

bool If all checks pass, true, otherwise false.

More Information

Returns false if in Comment_Moderation:

* The Administrator must approve all messages,
* The number of external links is too high, or
* Any banned word, name, URL, e-mail, or IP is found in any parameter except $comment_type.

Returns true if the Administrator does not have to approve all messages and:

* $comment_type parameter is a trackback or pingback and part of the blogroll, or
* $author and $email parameters have been approved previously.

Returns true in all other cases.

Source

function check_comment( $author, $email, $url, $comment, $user_ip, $user_agent, $comment_type ) {
	global $wpdb;

	// If manual moderation is enabled, skip all checks and return false.
	if ( 1 == get_option( 'comment_moderation' ) ) {
		return false;
	}

	/** This filter is documented in wp-includes/comment-template.php */
	$comment = apply_filters( 'comment_text', $comment, null, array() );

	// Check for the number of external links if a max allowed number is set.
	$max_links = get_option( 'comment_max_links' );
	if ( $max_links ) {
		$num_links = preg_match_all( '/<a [^>]*href/i', $comment, $out );

		/**
		 * Filters the number of links found in a comment.
		 *
		 * @since 3.0.0
		 * @since 4.7.0 Added the `$comment` parameter.
		 *
		 * @param int    $num_links The number of links found.
		 * @param string $url       Comment author's URL. Included in allowed links total.
		 * @param string $comment   Content of the comment.
		 */
		$num_links = apply_filters( 'comment_max_links_url', $num_links, $url, $comment );

		/*
		 * If the number of links in the comment exceeds the allowed amount,
		 * fail the check by returning false.
		 */
		if ( $num_links >= $max_links ) {
			return false;
		}
	}

	$mod_keys = trim( get_option( 'moderation_keys' ) );

	// If moderation 'keys' (keywords) are set, process them.
	if ( ! empty( $mod_keys ) ) {
		$words = explode( "\n", $mod_keys );

		foreach ( (array) $words as $word ) {
			$word = trim( $word );

			// Skip empty lines.
			if ( empty( $word ) ) {
				continue;
			}

			/*
			 * Do some escaping magic so that '#' (number of) characters in the spam
			 * words don't break things:
			 */
			$word = preg_quote( $word, '#' );

			/*
			 * Check the comment fields for moderation keywords. If any are found,
			 * fail the check for the given field by returning false.
			 */
			$pattern = "#$word#iu";
			if ( preg_match( $pattern, $author ) ) {
				return false;
			}
			if ( preg_match( $pattern, $email ) ) {
				return false;
			}
			if ( preg_match( $pattern, $url ) ) {
				return false;
			}
			if ( preg_match( $pattern, $comment ) ) {
				return false;
			}
			if ( preg_match( $pattern, $user_ip ) ) {
				return false;
			}
			if ( preg_match( $pattern, $user_agent ) ) {
				return false;
			}
		}
	}

	/*
	 * Check if the option to approve comments by previously-approved authors is enabled.
	 *
	 * If it is enabled, check whether the comment author has a previously-approved comment,
	 * as well as whether there are any moderation keywords (if set) present in the author
	 * email address. If both checks pass, return true. Otherwise, return false.
	 */
	if ( 1 == get_option( 'comment_previously_approved' ) ) {
		if ( 'trackback' !== $comment_type && 'pingback' !== $comment_type && '' !== $author && '' !== $email ) {
			$comment_user = get_user_by( 'email', wp_unslash( $email ) );
			if ( ! empty( $comment_user->ID ) ) {
				$ok_to_comment = $wpdb->get_var( $wpdb->prepare( "SELECT comment_approved FROM $wpdb->comments WHERE user_id = %d AND comment_approved = '1' LIMIT 1", $comment_user->ID ) );
			} else {
				// expected_slashed ($author, $email)
				$ok_to_comment = $wpdb->get_var( $wpdb->prepare( "SELECT comment_approved FROM $wpdb->comments WHERE comment_author = %s AND comment_author_email = %s and comment_approved = '1' LIMIT 1", $author, $email ) );
			}
			if ( ( 1 == $ok_to_comment ) &&
				( empty( $mod_keys ) || ! str_contains( $email, $mod_keys ) ) ) {
					return true;
			} else {
				return false;
			}
		} else {
			return false;
		}
	}
	return true;
}

Hooks

apply_filters( ‘comment_max_links_url’, int $num_links, string $url, string $comment )

Filters the number of links found in a comment.

apply_filters( ‘comment_text’, string $comment_text, WP_Comment|null $comment, array $args )

Filters the text of a comment to be displayed.

Changelog

VersionDescription
1.2.0Introduced.

User Contributed Notes

  1. Skip to note 2 content

    Simple use case

    $author = "John Charles Smith";
    $email = "jsmith@example.com";
    $url = "http://example.com&quot;;
    $comment = "Excellent...";
    $user_ip = "12.34.56.78";
    $user_agent = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.79 Safari/535.11";
    $comment_type = "comment";
    
    if ( check_comment( $author, $email, $url, $comment, $user_ip, $user_agent, $comment_type ) ) {
    	echo "The Comment robot says: Thank you for your comment.";
    } else {
    	echo "The Comment robot says: This comment is NOT valid!";
    }

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