Remove query var on admin pages when 'Save changes' pressed

Question

In the admin backend we use a query arg that is left in the URL and keeps getting used whether it is supposed to or not.

Our plugin has an array with values that can be toggled via the custom backend page. Against the option that should be toggled there is a link titled 'Activate' or 'Deactivate', pressing that link returns to the same admin page but with an added query arg which is parsed when the page is initialised. The admin page can be reloaded by following the toggle links or pressing the standard 'Save changes' backend button. The problem is that with the query arg remains in the URL when 'Save changes' is pressed, so the value is toggled again without the 'Activate' or 'Deactivate' being followed.

The arg should be removed when 'Save Changes' is pressed. Is there a filter for the 'Save changes' button so we could add our own filter to remove the custom arg?

class Custom_Admin {
private $options;

public function __construct()
{
    $this->options = get_option( 'custom_options' );
    add_filter('query_vars', array($this, 'add_query_vars'));
    add_action('init', array($this, 'check_query_vars') );
}

public function add_query_vars($public_query_vars) {
    $public_query_vars[] = 'code_key';
    return $public_query_vars;
}

public function check_query_vars() {
    $code_key = isset($_GET["code_key"]) ? $_GET["code_key"] : '';

    $active = $this->options[$code_key]['active'];
    $this->options[$code_key]['active'] = ($active == true ? false : true);

    update_option('custom_options', $this->options);
}

public function page_init()
{
    register_setting(
        'group', // Option group
        'options', // Option name
        array( $this, 'sanitize' ) // Sanitize
    );
}

public function sanitize($input)
{
    // Parse and sanitise more stuff here like a normal person
}

}

Answer 1

This might be useful: there is a filter called removable_query_args. You get an array of argument names to which you can append your own argument. Then WP will take care of removing all of the arguments in the list from the URL.

function add_removable_arg($args) {
    array_push($args, 'my-query-arg');
    return $args;
}

add_filter('removable_query_args', 'add_removable_arg');

Something like:

'...post.php?post=1&my-query-arg=10'

Will become:

'...post.php?post=1'

Answer 2

If you are using the Settings API for the Save Changes, you are probably using a nonce field with it (if not it is easy enough to add with wp_nonce_field whether you are using Settings API or not) ...

So testing for the presence of the nonce field is one way to test and help you distiguish between what action should be happening so as to not update the other custom option. eg.

public function check_query_vars() {
    // bug out here if nonce value is set
    if (isset($_REQUEST['_wpnonce'])) {return;}

    $code_key = isset($_GET["code_key"]) ? $_GET["code_key"] : '';

    $active = $this->options[$code_key]['active'];
    $this->options[$code_key]['active'] = ($active == true ? false : true);

    update_option('custom_options', $this->options);
}

Answer 3

Maybe JS will do what you want? This should be the easiest way to achieve what you want. More info about removing query string param in JS