Updated theme version, added update checker

functions.php

@@ -16,6 +16,7 @@
 require_once("vendor/autoload.php");
 
 $skycraft_includes = array(
+	'/theme-update-checker.php',			// Initialize Theme updater
 	'/theme-settings.php',                  // Initialize theme default settings.
 	'/setup.php',                           // Theme setup and custom theme supports.
 	'/widgets.php',                         // Register widget area.

inc/theme-update-checker.php

@@ -0,0 +1,308 @@
+<?php
+/**
+ * Theme Update Checker Library 1.2
+ * http://w-shadow.com/
+ * 
+ * Copyright 2012 Janis Elsts
+ * Licensed under the GNU GPL license.
+ * http://www.gnu.org/licenses/gpl.html
+ */
+
+if ( !class_exists('ThemeUpdateChecker') ):
+
+/**
+ * A custom theme update checker. 
+ * 
+ * @author Janis Elsts
+ * @copyright 2012
+ * @version 1.2
+ * @access public
+ */
+class ThemeUpdateChecker {
+	public $theme = '';              //The theme associated with this update checker instance.
+	public $metadataUrl = '';        //The URL of the theme's metadata file.
+	public $enableAutomaticChecking = true; //Enable/disable automatic update checks.
+
+	protected $optionName = '';      //Where to store update info.
+	protected $automaticCheckDone = false;
+	protected static $filterPrefix = 'tuc_request_update_';
+
+	/**
+	 * Class constructor.
+	 *
+	 * @param string $theme Theme slug, e.g. "twentyten".
+	 * @param string $metadataUrl The URL of the theme metadata file.
+	 * @param boolean $enableAutomaticChecking Enable/disable automatic update checking. If set to FALSE, you'll need to explicitly call checkForUpdates() to, err, check for updates.
+	 */
+	public function __construct($theme, $metadataUrl, $enableAutomaticChecking = true){
+		$this->metadataUrl = $metadataUrl;
+		$this->enableAutomaticChecking = $enableAutomaticChecking;
+		$this->theme = $theme;
+		$this->optionName = 'external_theme_updates-'.$this->theme;
+
+		$this->installHooks();		
+	}
+
+	/**
+	 * Install the hooks required to run periodic update checks and inject update info 
+	 * into WP data structures.
+	 * 
+	 * @return void
+	 */
+	public function installHooks(){
+		//Check for updates when WordPress does. We can detect when that happens by tracking
+		//updates to the "update_themes" transient, which only happen in wp_update_themes().
+		if ( $this->enableAutomaticChecking ){
+			add_filter('pre_set_site_transient_update_themes', array($this, 'onTransientUpdate'));
+		}
+
+		//Insert our update info into the update list maintained by WP.
+		add_filter('site_transient_update_themes', array($this,'injectUpdate')); 
+
+		//Delete our update info when WP deletes its own.
+		//This usually happens when a theme is installed, removed or upgraded.
+		add_action('delete_site_transient_update_themes', array($this, 'deleteStoredData'));
+	}
+
+	/**
+	 * Retrieve update info from the configured metadata URL.
+	 * 
+	 * Returns either an instance of ThemeUpdate, or NULL if there is 
+	 * no newer version available or if there's an error.
+	 * 
+	 * @uses wp_remote_get()
+	 * 
+	 * @param array $queryArgs Additional query arguments to append to the request. Optional.
+	 * @return ThemeUpdate 
+	 */
+	public function requestUpdate($queryArgs = array()){
+		//Query args to append to the URL. Themes can add their own by using a filter callback (see addQueryArgFilter()).
+		$queryArgs['installed_version'] = $this->getInstalledVersion(); 
+		$queryArgs = apply_filters(self::$filterPrefix.'query_args-'.$this->theme, $queryArgs);
+
+		//Various options for the wp_remote_get() call. Themes can filter these, too.
+		$options = array(
+			'timeout' => 10, //seconds
+		);
+		$options = apply_filters(self::$filterPrefix.'options-'.$this->theme, $options);
+
+		$url = $this->metadataUrl; 
+		if ( !empty($queryArgs) ){
+			$url = add_query_arg($queryArgs, $url);
+		}
+
+		//Send the request.
+		$result = wp_remote_get($url, $options);
+
+		//Try to parse the response
+		$themeUpdate = null;
+		$code = wp_remote_retrieve_response_code($result);
+		$body = wp_remote_retrieve_body($result);
+		if ( ($code == 200) && !empty($body) ){
+			$themeUpdate = ThemeUpdate::fromJson($body);
+			//The update should be newer than the currently installed version.
+			if ( ($themeUpdate != null) && version_compare($themeUpdate->version, $this->getInstalledVersion(), '<=') ){
+				$themeUpdate = null;
+			}
+		}
+
+		$themeUpdate = apply_filters(self::$filterPrefix.'result-'.$this->theme, $themeUpdate, $result);
+		return $themeUpdate;
+	}
+
+	/**
+	 * Get the currently installed version of our theme.
+	 * 
+	 * @return string Version number.
+	 */
+	public function getInstalledVersion(){
+		if ( function_exists('wp_get_theme') ) {
+			$theme = wp_get_theme($this->theme);
+			return $theme->get('Version');
+		}
+
+		/** @noinspection PhpDeprecationInspection get_themes() used for compatibility with WP 3.3 and below. */
+		foreach(get_themes() as $theme){
+			if ( $theme['Stylesheet'] === $this->theme ){
+				return $theme['Version'];
+			}
+		}
+		return '';
+	}
+
+	/**
+	 * Check for theme updates. 
+	 * 
+	 * @return void
+	 */
+	public function checkForUpdates(){
+		$state = get_option($this->optionName);
+		if ( empty($state) ){
+			$state = new StdClass;
+			$state->lastCheck = 0;
+			$state->checkedVersion = '';
+			$state->update = null;
+		}
+
+		$state->lastCheck = time();
+		$state->checkedVersion = $this->getInstalledVersion();
+		update_option($this->optionName, $state); //Save before checking in case something goes wrong 
+
+		$state->update = $this->requestUpdate();
+		update_option($this->optionName, $state);
+	}
+
+	/**
+	 * Run the automatic update check, but no more than once per page load.
+	 * This is a callback for WP hooks. Do not call it directly.  
+	 * 
+	 * @param mixed $value
+	 * @return mixed
+	 */
+	public function onTransientUpdate($value){
+		if ( !$this->automaticCheckDone ){
+			$this->checkForUpdates();
+			$this->automaticCheckDone = true;
+		}
+		return $value;
+	}
+
+	/**
+	 * Insert the latest update (if any) into the update list maintained by WP.
+	 * 
+	 * @param StdClass $updates Update list.
+	 * @return array Modified update list.
+	 */
+	public function injectUpdate($updates){
+		$state = get_option($this->optionName);
+
+		//Is there an update to insert?
+		if ( !empty($state) && isset($state->update) && !empty($state->update) ){
+			$updates->response[$this->theme] = $state->update->toWpFormat();
+		}
+
+		return $updates;
+	}
+
+	/**
+	 * Delete any stored book-keeping data.
+	 * 
+	 * @return void
+	 */
+	public function deleteStoredData(){
+		delete_option($this->optionName);
+	} 
+
+	/**
+	 * Register a callback for filtering query arguments. 
+	 * 
+	 * The callback function should take one argument - an associative array of query arguments.
+	 * It should return a modified array of query arguments.
+	 * 
+	 * @param callable $callback
+	 * @return void
+	 */
+	public function addQueryArgFilter($callback){
+		add_filter(self::$filterPrefix.'query_args-'.$this->theme, $callback);
+	}
+
+	/**
+	 * Register a callback for filtering arguments passed to wp_remote_get().
+	 * 
+	 * The callback function should take one argument - an associative array of arguments -
+	 * and return a modified array or arguments. See the WP documentation on wp_remote_get()
+	 * for details on what arguments are available and how they work. 
+	 * 
+	 * @param callable $callback
+	 * @return void
+	 */
+	public function addHttpRequestArgFilter($callback){
+		add_filter(self::$filterPrefix.'options-'.$this->theme, $callback);
+	}
+
+	/**
+	 * Register a callback for filtering the theme info retrieved from the external API.
+	 * 
+	 * The callback function should take two arguments. If a theme update was retrieved 
+	 * successfully, the first argument passed will be an instance of  ThemeUpdate. Otherwise, 
+	 * it will be NULL. The second argument will be the corresponding return value of 
+	 * wp_remote_get (see WP docs for details).
+	 *  
+	 * The callback function should return a new or modified instance of ThemeUpdate or NULL.
+	 * 
+	 * @param callable $callback
+	 * @return void
+	 */
+	public function addResultFilter($callback){
+		add_filter(self::$filterPrefix.'result-'.$this->theme, $callback, 10, 2);
+	}
+}
+
+endif;
+
+if ( !class_exists('ThemeUpdate') ):
+
+/**
+ * A simple container class for holding information about an available update.
+ * 
+ * @author Janis Elsts
+ * @copyright 2012
+ * @version 1.0
+ * @access public
+ */
+class ThemeUpdate {
+	public $version;      //Version number.
+	public $details_url;  //The URL where the user can learn more about this version. 
+	public $download_url; //The download URL for this version of the theme. Optional.
+
+	/**
+	 * Create a new instance of ThemeUpdate from its JSON-encoded representation.
+	 * 
+	 * @param string $json Valid JSON string representing a theme information object. 
+	 * @return ThemeUpdate New instance of ThemeUpdate, or NULL on error.
+	 */
+	public static function fromJson($json){
+		$apiResponse = json_decode($json);
+		if ( empty($apiResponse) || !is_object($apiResponse) ){
+			return null;
+		}
+
+		//Very, very basic validation.
+		$valid = isset($apiResponse->version) && !empty($apiResponse->version) && isset($apiResponse->details_url) && !empty($apiResponse->details_url);
+		if ( !$valid ){
+			return null;
+		}
+
+		$update = new self();
+		foreach(get_object_vars($apiResponse) as $key => $value){
+			$update->$key = $value;
+		}
+
+		return $update;
+	}
+
+	/**
+	 * Transform the update into the format expected by the WordPress core.
+	 * 
+	 * @return array
+	 */
+	public function toWpFormat(){
+		$update = array(
+			'new_version' => $this->version,
+			'url' => $this->details_url,
+		);
+
+		if ( !empty($this->download_url) ){
+			$update['package'] = $this->download_url;
+		}
+
+		return $update;
+	}
+}
+
+endif;
+
+$MyThemeUpdateChecker = new ThemeUpdateChecker(
+	'skycraft',
+	'https://skyraptor.eu/wp-update-server/?action=get_metadata&slug=skycraft'
+);

style.css

@@ -1,10 +1,11 @@
 /*
 Theme Name: SkyCraft
 Theme URI: https://skyraptor.eu/portfolio
+Details URI: https://skyraptor.eu/skycraft
 Author: Patrick Henninger
 Author URI: https://skyraptor.eu
-Description: TO DO
-Version: 2.5.0
+Description: SkyCraft WordPress Theme for Minecraft oriented WordPress sites including Server status.
+Version: 3.0.0
 License: skycraft WordPress Theme, Copyright 2013-2017 Holger Koenemann
 Text Domain: skycraft
 Tags: one-column, custom-menu, featured-images, theme-options, translation-ready