GigaOM Custom Post Type Factory

This is a convenience class and collection of methods to make creating new custom post types with their own metaboxes easy.

The general idea is to define a function that's hooked to the register_post_types action. The function defines a class for your post type that extends the GO_Cpt class. This follows a design pattern established by the modern widgets API (as introduced in WP 2.8) http://codex.wordpress.org/Widgets_API#Developing_Widgets .

The result is a new custom post type and much easier creation and updating of custom meta associated with that post type. You'll also have a convenient object you can use to access the metadata associated with each post.

function my_customposttype()
{
    class My_CustomPostType extends GO_Cpt
    {
        function __construct()
        {
            // execute the parent constructor with the name 
            // and definition for the custom post type
            parent::__construct( $post_type_name , $post_type_definition );
        }
    
        function metabox( $post , $meta )
        {
            // print out the form here
            // 
            // this method is optional, only use it if you want to 
            // add a metabox to your custom post type
        }

        function update( $new_meta , $old_meta )
        {
            // sanitize and validate the metadata
            // then return $meta so it can be saved
            //
            // this method is required if a 
            // metabox() method is included
            
        }
    }

    global $my_customposttype;
    $my_customposttype = new My_CustomPostType;
}

// hook that function to the register_post_types action
add_action( 'register_post_types' , 'my_customposttype' );

Backstory: defining the post type class inside the function avoids issues with loading order and fatal errors resulting from attempting to extend a class that might not exist yet. Isn't PHP awesome?

See the included hello world example: http://plugins.trac.wordpress.org/browser/go-cptfactory/trunk/example-helloworld-cpt.php

To access the meta associated with a post, you can call $my_customposttype->get_meta( $post_id );

You can easily add a method and hook to filter the_content or the_excerpt to insert custom values that may have been entered in the post meta. Simply add add_filter( 'the_content' , array( $this , 'the_content' )); in the __construct() and then define another method in the My_CustomPostType class such as:`

    function the_content( $content )
    { 
        $meta_print = print_r( $this->get_meta( get_the_ID() ) , TRUE ); 
        return $meta_print . $content 
    }

`