Generic WP Plugin Admin Menu Implementation - with AJAX!

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<?php
/*
Plugin Name: Generic Menu
Plugin URI: http://example.com/
Description: Move things
Author: dalethedeveloper
Version: 0.1
*/
new myadmin_generic();

class myadmin_generic {
    protected $nonce_string = 'myadmin_generic_nonce_string';
    protected $ajax_slug = 'myadmin';

    /**
     * Sitewide plugin defaults
     */
    public static $option_defaults = array(
                                    'generic_opt_bool' => 'no',
                                    'generic_opt_num' => '1',
                                    'generic_opt_text' => '',
                                );

    public function __construct() {
        add_action('admin_menu', array($this, 'admin_menus'));
        add_action('wp_ajax_'.$this->ajax_slug, array($this,'ajax_handler'));
        add_action('admin_head',array($this,'ajax_script'));
    }

    /**
     * Register Admin page and filtering
     */
    public function admin_menus() {
        // Example Settings Page, Editors and up
		add_menu_page(
				'Generic Settings Menu',
				'Generic Menu',
				'edit_posts',
				'myadmin',
				array($this,'show_admin_page')
			);
		// Example Administrator Only Subpage
        add_submenu_page(
				'myadmin',
				'Admin Settings',
				'Admin Setings',
				'activate_plugins',
				'myadmin_page',
				array($this,'show_admin_subpage')
			);
    }

	/**
	 * Handle AJAX calls to and fro, assuming jQuery is doing the hard work.
	 */
    public function ajax_handler() {
        check_ajax_referer($this->nonce_string,'security');

		// $this->save_settings(true);

        $response = array('message' => $_POST['generic_opt_text']);

        header('Content-Type: application/json');
        exit( json_encode($response) );
    }

    /**
     * Output javascript with noncing for AJAX requests
     */
    public function ajax_script() {
        $nonce = wp_create_nonce($this->nonce_string);
        echo <<<JS

<script type="text/javascript">
jQuery(document).ready(function($) {
    $('form[name="myadmin_opts"]').delegate('input.button-primary.ajax','click',function(){

        var input = $(this).closest('form').serialize(),
			parent = $(this).parent(),
            loading = $('.ajax-feedback',parent);

        if( loading.css('visibility') !== 'visible' ) {
            $('div.updated',parent).remove();
            loading.css('visibility','visible');
            $.ajax({
              type: 'POST',
              url: ajaxurl,
              data: input + '&action={$this->ajax_slug}&security={$nonce}',
              dataType: 'json',
              timeout : 30000,
              success: function(data, textStatus, jqXHR) {
                    if( data ) {
                        if( data.message )
                            $('<div class="updated"><p><strong>' + data.message + '</strong></p></div>').appendTo( parent ).delay(1000).fadeOut();

                        if( data.error )
                            $('<div class="updated"><p><strong>Error: ' + data.error + '</strong></p></div>').appendTo( parent ).delay(1000).fadeOut();

                        if( data.reload )
                            window.location.reload();
                    }
                },
              complete: function(jqXHR, textStatus) {
                  loading.css('visibility','hidden');
                  if( textStatus !== 'success' )
                      $('<div class="updated"><p><strong>Unable to completed that action, please try again.</strong></p></div>').appendTo( parent );
              }
            });
        }
        return false;
    });
});
</script>

JS;
    }
    /**
     * Save $_POST options on posting
     *
     * @return bool TRUE on saved, FALSE on not saved
     */
    public function save_settings($not_ajax = true) {
        if( $_POST and !empty($_POST['myadmin_form_nonce']) and wp_verify_nonce( $_POST['myadmin_form_nonce'],$this->nonce_string ) ) {
            foreach( array_keys(self::$option_defaults) as $option ) {
                if( isset($_POST[$option]) )
                    update_option($option,$_POST[$option]);
            }
			if( $not_ajax )
				echo '<div class="updated"><p><strong>Settings Saved.</strong></p></div>';
            return true;
        }
        return false;
    }

    /**
     * Output an admin form wrapping our interior options panes
     */
    public function output_form( $content ) {
        $nonceid = wp_create_nonce($this->nonce_string);
        echo <<<HTML
        <div class="wrap">
            <form name="myadmin_opts" method="post" action="">
                {$content}
                <input type="hidden" name="myadmin_form_nonce" id="myadmin_form_nonce" value="{$nonceid}" />
            </form>
        </div>
HTML;
    }

    /**
     * Quick check for permissions, for URL tomfoolery
     *
     * @param type $cap Capability
     */
    public function check_perm($cap) {
        if( !current_user_can($cap) ) {
            $msg = <<<MSG
        <div class="wrap">
                <h2>Permission Denied</h2>
                <p>
                        You do not have permission to change these settings.  Please contact your site administrator.
                </p>
        </div>
MSG;
            wp_die($msg);
        }
    }

    /**
     * Settings page for Generic Admin
     */
    public function show_admin_page() {
        $this->check_perm('manage_options');
		$this->save_settings();

		// Load Options
        $opt_text = get_option('generic_opt_text');

		$opt_bool = get_option('generic_opt_bool','no');
        $opt_bool_yes = ($opt_bool == 'yes') ? 'checked="checked" ' : '';
        $opt_bool_no = ($opt_bool == 'no') ? 'checked="checked" ' : '';

        $opt_num = (int) get_option('generic_opt_num','1');
        $opt_num_select = '<select name="generic_opt_num" id="generic_opt_num">';
        for($i=1;$i<=5;$i++) {
            $opt_num_select .= '<option '.($opt_num==$i?'selected="selected"':'').">$i</option>";
        }
        $opt_num_select .= '</select>';

        $body =  <<<HTML
            <h2>Admin Menu Title</h2>
                <h3>Subtitle</h3>
                <p>
                    A pleasant description of our Options.
                </p>
                <table class="form-table">
                    <tr valign="top">
                        <th scope="row">Text Option</th>
                        <td>
                            <input type="text" name="generic_opt_text" id="generic_opt_text" value="{$opt_text}"/>
                        </td>
                    </tr>
                    <tr valign="top">
                        <th scope="row">Numeric Dropdown Option</th>
                        <td>
                            {$opt_num_select}
                        </td>
                    </tr>
                    <tr valign="top">
                        <th scope="row">Boolean Radio Option</th>
                        <td>
                            <input type="radio" name="generic_opt_bool" value="yes" {$opt_bool_yes} /> Yes <br/>
                            <input type="radio" name="generic_opt_bool" value="no" {$opt_bool_no} /> No
                        </td>
                    </tr>
                </table>
                <p class="submit">
                    <input type="submit" name="Submit" class="button-primary" value="Save Changes" />
                </p>
HTML;
        $this->output_form($body);
    }


    public function show_admin_subpage() {
        $this->check_perm('manage_options');
        $this->save_settings();

		$loading_img = esc_url( admin_url( 'images/wpspin_light.gif' ) );

        $body = <<<HTML
            <h2>Admin Settings</h2>
                <h3>With bonus AJAX Calls!</h3>
                <p>
                    Data is passed from the form below back to the class via jQuery.
                </p>
                <table class="form-table">
                    <tr valign="top">
                        <th scope="row">Post this data back via AJAX:</th>
                        <td>
                            <input type="text" name="generic_opt_text" id="generic_opt_text" value="Form input."/>
                        </td>
                    </tr>
                </table>
                <p class="submit">
                    <input type="submit" name="Submit" class="button-primary ajax" value="Save Changes" />
					<img src="{$loading_img}" class="ajax-feedback" title="" alt="" />
                </p>
HTML;
        $this->output_form($body);
    }
}