The following describes how to filter links and SQL statements in WordPress: _ PHP Tutorial

Describes how to filter links and SQL statements in WordPress ,. The method for filtering links and SQL statements in WordPress is described in detail. many URLs of esc_url () (filtering links) may have small errors. you can use the esc_url () function to block or correct these errors, describes how to filter links and SQL statements in WordPress,

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

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Large, esc_url () (filtering links) many URLs may have some minor errors. you can use the esc_url () function to block or correct these errors ,...