How to filter links and SQL statements in WordPress

: This article describes how to filter links and SQL statements in WordPress. For more information about PHP tutorials, see. Esc_url () (filter link)
Many URLs have small errors. Using the esc_url () function can block or correct these errors and reject insecure protocols.

Work content of the esc_url () function:

The default DENY is not the URL of the following protocol: defaulting to http, https, ftp, ftps, mailto, news, irc, gopher, nntp, feed, and telnet.
Delete invalid and dangerous characters
Convert characters into HTML entity characters
Usage

esc_url( $url, $protocols, $_context );

Parameters

$ Url

(String) (required) the URL to be filtered.

Default value: None

$ Protocols

(Array) (optional) an array that can receive protocols. If no protocol is set, the default value is: defaulting to http, https, ftp, ftps, mailto, news, irc, gopher, nntp, feed, and telnet.

Default value: None

$ _ Context

(String) (optional) how to return a URL.

Default value: (string) display

Return value

(String) returns the filtered link.

Example

<? Php echo esc_url ('www .endskin.com '); // output: http://www.endskin.com?>

More

This function is located in: wp-includes/formatting. php

Esc_ SQL () (filter SQL statements)
Esc_ SQL () is used to filter the strings to be added to SQL statements to prevent SQL injection and exceptions caused by data interference.

Usage

esc_sql( $data );

Parameters

$ Data

(String) (required) the string to be filtered.

Default value: None

Return value

(String) the filtered string can be directly added to the SQL statement.

Example

$name = esc_sql( $name );$status = esc_sql( $status );$wpdb->get_var( "SELECT something FROM table WHERE foo = '$name' and status = '$status'" );

More

This function is located in: wp-includes/formatting. php

The above describes how to filter links and SQL statements in WordPress, including related content, and hope to help those who are interested in PHP tutorials.