Using WordPress ‘pre_option’ PHP filter

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WordPress ‘pre_option’ PHP filter allows you to modify the value of an option before it is retrieved from the database.

Usage

To use the apply_filters() function, add the following code to your theme’s functions.php file or a custom plugin file:

add_filter( 'pre_option', 'your_function_name', 10, 3 );
function your_function_name( $pre_option, $option, $default_value ) {
    // Your code here
}

Parameters

  • $pre_option (mixed): The value to return instead of the option value. Default is false (to skip past the short-circuit).
  • $option (string): Name of the option.
  • $default_value (mixed): The fallback value to return if the option does not exist. Default is false.

Examples

Set a default site title

add_filter( 'pre_option', 'set_default_site_title', 10, 3 );
function set_default_site_title( $pre_option, $option, $default_value ) {
    if ( $option == 'blogname' && empty( $pre_option ) ) {
        return 'My Default Site Title';
    }
    return $pre_option;
}

This code sets a default site title, “My Default Site Title”, if the ‘blogname’ option is empty.

Enable maintenance mode

add_filter( 'pre_option', 'enable_maintenance_mode', 10, 3 );
function enable_maintenance_mode( $pre_option, $option, $default_value ) {
    if ( $option == 'maintenance_mode' ) {
        return true;
    }
    return $pre_option;
}

This code enables maintenance mode by setting the ‘maintenance_mode’ option to true.

Set a default timezone

add_filter( 'pre_option', 'set_default_timezone', 10, 3 );
function set_default_timezone( $pre_option, $option, $default_value ) {
    if ( $option == 'timezone_string' && empty( $pre_option ) ) {
        return 'America/New_York';
    }
    return $pre_option;
}

This code sets a default timezone, “America/New_York”, if the ‘timezone_string’ option is empty.

Set default image sizes

add_filter( 'pre_option', 'set_default_image_sizes', 10, 3 );
function set_default_image_sizes( $pre_option, $option, $default_value ) {
    switch ( $option ) {
        case 'thumbnail_size_w':
            return 150;
        case 'thumbnail_size_h':
            return 150;
        case 'medium_size_w':
            return 300;
        case 'medium_size_h':
            return 300;
        case 'large_size_w':
            return 1024;
        case 'large_size_h':
            return 1024;
        default:
            return $pre_option;
    }
}

This code sets default image sizes for thumbnail, medium, and large images if their corresponding options are not set.

Limit number of posts per page

add_filter( 'pre_option', 'limit_posts_per_page', 10, 3 );
function limit_posts_per_page( $pre_option, $option, $default_value ) {
    if ( $option == 'posts_per_page' ) {
        return 5;
    }
    return $pre_option;
}

This code limits the number of posts displayed per page to 5 by setting the ‘posts_per_page’ option to 5.