What are the advantages to the Settings API?

Let me preface this by saying that I hardly ever work with WordPress – in fact, the last time I did a site in WordPress was back during 2.2. Yesterday I made quite a mess of everything and asked several questions here trying to get a basic menu plugin working.

I now have the plugin fully functional and behaving exactly as I expect, so I decided to make minor changes here and there to add functionality and compatibility – including using the Settings API. However a very short moment into reading tutorials on this API and I became quite confused, then this confusion only deepened as I read on and tried to implement the examples – which was made even more difficult by the fact that my plugin is implemented as a class.

Unless I’m doing something wrong, from what I understand to use the Settings API requires the creation of a new function PER SETTING. This means 3-5 functions for the average plugin, and up to hundreds for more advanced plugins. It just seems ludicrous to write this many functions (and develop a naming system to keep from confusing them) when you could just as easily import all applicable $_POST variables into an array and forego the entire mess.

Perhaps I’m old-fashioned, but unless there’s something to gain from it I don’t see the reason to triple or quadruple how much code I’m writing. Here’s how I managed options before attempting to add the Settings API:

    function __construct() {
        /* constructor stuff */
        $this->options = $this->db_options = get_option( 'de-menu-options' );
        if( $this->options === false ){
            $this->options = $this->defaults;
        }
        if (is_admin()) {
            add_action('admin_menu', array(&$this, 'admin_menu'));
        }   
        /* more stuff */

        // When WordPress shuts down we store changes to options
        add_action('shutdown', array(&$this, 'update'));
    }

    public function admin_menu() {
        add_options_page('DE Menu Options', 'DE Menu', 'manage_options', 'de-menu-options', array(&$this, 'options'));
        add_option('de-menu-options', $this->options);
    }

    public function options() {
        if (!current_user_can('manage_options')) {
            wp_die( __('You do not have sufficient permissions to access this page.') );
        }
        if ( !empty($_POST) && check_admin_referer('de-menu-options') ) {
            // These options are saved to the database at shutdown
            $this->options = array(
                "columns" => $_POST["de-menu-columns"],
                "maintenance" => $_POST["de-menu-maintenance"]
            );
            echo 'DE Menu options saved';
        }
?>

<div class="wrap">
    <h2>DE Menu Plugin</h2>
    <form method="post" action="<?php echo $_SERVER['REQUEST_URI']; ?>">
        <?php settings_fields('de-menu-options'); ?>
        <input type="checkbox" name="de-menu-maintenance" />
        <label for="de-menu-columns">Columns:</label>
        <input type="text" name="de-menu-columns" value="<?php echo $this->options['columns']; ?>" />
        <p class="submit">
        <input type="submit" name="de-menu-submit" value="Update Options »" />
        </p>
    </form>
</div>
<?php
    }

    function update() {
        // By storing all changes at the end we avoid multiple database calls
        $diff = array_diff( $this->options, $this->db_options );
        if( !empty( $diff )  ){
            update_option('de-menu-options', $this->options);
        }
    }

Now with the settings API I have something more like the following:

    function __construct() {
        /* constructor stuff */
        // Do I load options? Will they be loaded for me? Who knows?
        if (is_admin()) {
            add_action('admin_menu', array(&$this, 'admin_menu'));
            add_action('admin_init', array(&$this, 'admin_init'));
        }   
        /* more stuff */
        // Settings API should update options for me... I think
    }

    public function admin_menu() {
        add_options_page('DE Menu Options', 'DE Menu', 'manage_options', 'de-menu-options', array(&$this, 'options'));
        add_option('de-menu-options', $this->options);
    }

    public function admin_init() {
        register_setting('de-menu-options','de-menu-options',array(&$this,'validate'));
        add_settings_section('de-menu-main-options', 'Main Settings', 'options_section', 'de-menu-options');
        add_settings_field('de-menu-maintenance', 'Maintenance Mode', array(&$this,'options_maintenance'), 'de-menu-options', 'de-menu-main-options');
        add_settings_field('de-menu-columns', 'Columns', array(&$this,'options_columns'), 'de-menu-options', 'de-menu-main-options');
    }

    public function options() {
        if (!current_user_can('manage_options')) {
            wp_die( __('You do not have sufficient permissions to access this page.') );
        }
        if ( !empty($_POST) && check_admin_referer('de-menu-options') ) {
            // These options are saved to the database at shutdown
            $this->options = array(
                "columns" => $_POST["de-menu-columns"],
                "maintenance" => $_POST["de-menu-maintenance"]
            );
            echo 'DE Menu options saved';
        }
?>

<div class="wrap">
    <h2>DE Menu Plugin</h2>
    <form method="post" action="<?php echo $_SERVER['REQUEST_URI']; ?>">
        <?php settings_fields('de-menu-options'); ?>
        <?php do_settings_sections('de-menu-options'); ?>
        <p class="submit">
        <input type="submit" name="de-menu-submit" value="Update Options »" />
        </p>
    </form>
</div>
<?php
    }

    public function options_section() {
        echo '<p>' . __('Main description of this section here.','de-menu-lang') . '</p>';
    }

    public function options_maintenance() {
        echo "<input id='de-menu-maintenance' name='options[maintenance]' type='checkbox' />";
    }

    public function options_columns() {
        echo "<input id='de-menu-columns' name='options[columns]' type='checkbox' value=".$this->options['columns']."/>";
    }

    function validate($options) {
        return $options; // I guess?
    }

It’s probably painfully obvious from the scrollbars that the code is already longer with just two options. It’s like-wise obvious from the comments that I don’t entirely understand what I’m doing. Then there’s the matter of having 5 new functions (and removing only 1) in order to accomplish all of this.

So just what advantage am I gaining from all of this extra work?