Example query var processing

<?php
/*
Plugin Name: Zed1 test
Plugin URI: http://zed1.com/
Description: Test plugin
Author: Mike Little
Version: 0.0.1
Author URI: http://zed1.com/
Author URI: http://zed1.com/
License: GPL2+
*/
/*
    Copyright 2011  Mike Little  (email : mike@zed1.com)

    This file is part of The Zed1 test  Plugin.

    The Zed1 test  Plugin is free software:
    you can redistribute it and/or modify it under the terms of the
    GNU General Public License as published by the Free Software Foundation,
    either version 2 of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

define('ZED1_TEST_PLUGIN_NAME', 'zed1_test');
define('ZED1_TEST_PLUGIN_VERSION', '0.0.1');
define('ZED1_TEST_DEBUG', false); //true

if (!defined('NL')) define('NL', "\n");

new zed1_test();

class zed1_test {
    static $my_data;

    function zed1_test() {
        return $this->__construct();
    } // end php4 constructor

    function __construct() {
        error_log("zed1_test:constructor");
        add_action( 'init', array( 'zed1_test', 'init' ) );
    } // end constructor

    static function get_my_data() {
        return self::$my_data;
    } // end get_my_data

    static function set_my_data($val) {
        return self::$my_data = $val;
    } // end set_my_data

    static function init() {
        error_log("zed1_test:init");
        add_action( 'template_redirect', array( 'zed1_test', 'template_redirect_process_query_vars' ) );
        add_filter( 'wp_title', array( 'zed1_test', 'wp_title_display_my_title' ), 99, 3 ); // we want to be last
        add_filter( 'the_title', array( 'zed1_test', 'the_title_display_my_title' ), 99, 2 ); // we want to be last
        add_filter( 'the_content', array( 'zed1_test', 'the_content_display_results' ), 99 ); // we want to be last
    } // end init

    static function template_redirect_process_query_vars() {
        error_log("zed1_test:template_redirect_process_query_vars");
        if ( is_singular()  && isset($_GET['recid'] ) ) {
            //validate everything! It's coming from the nasty outside world
            $recid = intval( $_GET['recid'] );
            // run some code to get the record
            $my_data = array( 'title' => 'the record title ' . $recid ,
                              'content' => 'the records content ' . $recid ,
                            );
            // save it
            self::set_my_data($my_data);
        }
    } // end template_redirect_process_query_vars

    static function wp_title_display_my_title( $title, $sep, $seplocation ) {
        error_log("zed1_test:wp_title_display_my_title");
        if ( is_singular() ) {
            $my_data = self::get_my_data();
            if ( ! empty( $my_data ) )
                $title = '<title>my title: ' . $my_data['title'] . '</title>';
        }
        return $title;
    } // end the_content_display_results

    static function the_title_display_my_title( $title, $post_id ) {
        error_log("zed1_test:the_title_display_my_title");
        if ( is_singular() ) {
            $my_data = self::get_my_data();
            if ( ! empty( $my_data ) )
                $title = 'my title: ' . $my_data['title'] . '</title>';
        }
        return $title;
    } // end the_content_display_results

    static function the_content_display_results( $content ) {
        error_log("zed1_test:the_content_display_results");
        if ( is_singular() ) {
            $my_data = self::get_my_data();
            if ( ! empty( $my_data ) )
                $content = 'my content: ' . $my_data['content'];
        }
        return $content;
    } // end the_content_display_results


} // end class zed1_test