Dynamic WordPress Page Templates from a Plugin

1 comment

1. Here is my code solution (inspired by Tom McFarlin).

   This is designed for a plugin (the template files are searched for in the root directory of the plugin). This can be changed if desired – check out my full tutorial http://www.wpexplorer.com/wordpress-page-templates-plugin/ for greater detail on this solution. These files are also in exactly the same format as if they were to be included directly in a theme.

   To customise, simply edit the following code block within the __construct method;

      $this->templates = array(
          'goodtobebad-template.php'     => 'It's Good to Be Bad',
      );
   

   Full code;

   class PageTemplater {
   
       /**
        * A Unique Identifier
        */
        protected $plugin_slug;
   
       /**
        * A reference to an instance of this class.
        */
       private static $instance;
   
       /**
        * The array of templates that this plugin tracks.
        */
       protected $templates;
   
   
       /**
        * Returns an instance of this class. 
        */
       public static function get_instance() {
   
               if( null == self::$instance ) {
                       self::$instance = new PageTemplater();
               } 
   
               return self::$instance;
   
       } 
   
       /**
        * Initializes the plugin by setting filters and administration functions.
        */
       private function __construct() {
   
               $this->templates = array();
   
   
               // Add a filter to the attributes metabox to inject template into the cache.
               add_filter(
                   'page_attributes_dropdown_pages_args',
                    array( $this, 'register_project_templates' ) 
               );
   
   
               // Add a filter to the save post to inject out template into the page cache
               add_filter(
                   'wp_insert_post_data', 
                   array( $this, 'register_project_templates' ) 
               );
   
   
               // Add a filter to the template include to determine if the page has our 
               // template assigned and return it's path
               add_filter(
                   'template_include', 
                   array( $this, 'view_project_template') 
               );
   
   
               // Add your templates to this array.
               $this->templates = array(
                       'goodtobebad-template.php'     => 'It's Good to Be Bad',
               );
   
       } 
   
   
       /**
        * Adds our template to the pages cache in order to trick WordPress
        * into thinking the template file exists where it doens't really exist.
        *
        */
   
       public function register_project_templates( $atts ) {
   
               // Create the key used for the themes cache
               $cache_key = 'page_templates-' . md5( get_theme_root() . '/' . get_stylesheet() );
   
               // Retrieve the cache list. 
               // If it doesn't exist, or it's empty prepare an array
               $templates = wp_get_theme()->get_page_templates();
               if ( empty( $templates ) ) {
                       $templates = array();
               } 
   
               // New cache, therefore remove the old one
               wp_cache_delete( $cache_key , 'themes');
   
               // Now add our template to the list of templates by merging our templates
               // with the existing templates array from the cache.
               $templates = array_merge( $templates, $this->templates );
   
               // Add the modified cache to allow WordPress to pick it up for listing
               // available templates
               wp_cache_add( $cache_key, $templates, 'themes', 1800 );
   
               return $atts;
   
       } 
   
       /**
        * Checks if the template is assigned to the page
        */
       public function view_project_template( $template ) {
   
               global $post;
   
               if (!isset($this->templates[get_post_meta( 
                   $post->ID, '_wp_page_template', true 
               )] ) ) {
   
                       return $template;
   
               } 
   
               $file = plugin_dir_path(__FILE__). get_post_meta( 
                   $post->ID, '_wp_page_template', true 
               );
   
               // Just to be safe, we check if the file exist first
               if( file_exists( $file ) ) {
                       return $file;
               } 
               else { echo $file; }
   
               return $template;
   
       } 
   
   
   } 
   
   add_action( 'plugins_loaded', array( 'PageTemplater', 'get_instance' ) );
   

   Check out my tutorial on this for more info.

   http://www.wpexplorer.com/wordpress-page-templates-plugin/

   I hope this helps you in what you want to do 🙂

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