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authorGravatar Marien Fressinaud <dev@marienfressinaud.fr> 2015-01-31 14:45:37 +0100
committerGravatar Marien Fressinaud <dev@marienfressinaud.fr> 2015-01-31 14:45:37 +0100
commita97bbd9bd54c5fa56d54b3c214cf4e8af96af8b2 (patch)
tree6e83890bc1b3814a12c3b7bedc0d5944f30f507b /lib/Minz/ExtensionManager.php
parent42fd539a1b14f883077048a35864b4294b6efe94 (diff)
parente91b72b63cd11ae3c4f59e48439e93955242c673 (diff)
Merge branch 'dev'
Conflicts: CHANGELOG README.fr.md README.md app/Controllers/feedController.php app/Controllers/indexController.php app/i18n/en.php app/i18n/fr.php app/views/helpers/view/normal_view.phtml app/views/stats/index.phtml app/views/stats/repartition.phtml constants.php p/scripts/main.js
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+<?php
+
+/**
+ * An extension manager to load extensions present in EXTENSIONS_PATH.
+ *
+ * @todo see coding style for methods!!
+ */
+class Minz_ExtensionManager {
+ private static $ext_metaname = 'metadata.json';
+ private static $ext_entry_point = 'extension.php';
+ private static $ext_list = array();
+ private static $ext_list_enabled = array();
+
+ private static $ext_auto_enabled = array();
+
+ // List of available hooks. Please keep this list sorted.
+ private static $hook_list = array(
+ 'entry_before_display' => array( // function($entry) -> Entry | null
+ 'list' => array(),
+ 'signature' => 'OneToOne',
+ ),
+ 'entry_before_insert' => array( // function($entry) -> Entry | null
+ 'list' => array(),
+ 'signature' => 'OneToOne',
+ ),
+ 'feed_before_insert' => array( // function($feed) -> Feed | null
+ 'list' => array(),
+ 'signature' => 'OneToOne',
+ ),
+ 'post_update' => array( // function(none) -> none
+ 'list' => array(),
+ 'signature' => 'NoneToNone',
+ ),
+ );
+ private static $ext_to_hooks = array();
+
+ /**
+ * Initialize the extension manager by loading extensions in EXTENSIONS_PATH.
+ *
+ * A valid extension is a directory containing metadata.json and
+ * extension.php files.
+ * metadata.json is a JSON structure where the only required fields are
+ * `name` and `entry_point`.
+ * extension.php should contain at least a class named <name>Extension where
+ * <name> must match with the entry point in metadata.json. This class must
+ * inherit from Minz_Extension class.
+ */
+ public static function init() {
+ $list_potential_extensions = array_values(array_diff(
+ scandir(EXTENSIONS_PATH),
+ array('..', '.')
+ ));
+
+ $system_conf = Minz_Configuration::get('system');
+ self::$ext_auto_enabled = $system_conf->extensions_enabled;
+
+ foreach ($list_potential_extensions as $ext_dir) {
+ $ext_pathname = EXTENSIONS_PATH . '/' . $ext_dir;
+ if (!is_dir($ext_pathname)) {
+ continue;
+ }
+ $metadata_filename = $ext_pathname . '/' . self::$ext_metaname;
+
+ // Try to load metadata file.
+ if (!file_exists($metadata_filename)) {
+ // No metadata file? Invalid!
+ continue;
+ }
+ $meta_raw_content = file_get_contents($metadata_filename);
+ $meta_json = json_decode($meta_raw_content, true);
+ if (!$meta_json || !self::isValidMetadata($meta_json)) {
+ // metadata.json is not a json file? Invalid!
+ // or metadata.json is invalid (no required information), invalid!
+ Minz_Log::warning('`' . $metadata_filename . '` is not a valid metadata file');
+ continue;
+ }
+
+ $meta_json['path'] = $ext_pathname;
+
+ // Try to load extension itself
+ $extension = self::load($meta_json);
+ if (!is_null($extension)) {
+ self::register($extension);
+ }
+ }
+ }
+
+ /**
+ * Indicates if the given parameter is a valid metadata array.
+ *
+ * Required fields are:
+ * - `name`: the name of the extension
+ * - `entry_point`: a class name to load the extension source code
+ * If the extension class name is `TestExtension`, entry point will be `Test`.
+ * `entry_point` must be composed of alphanumeric characters.
+ *
+ * @param $meta is an array of values.
+ * @return true if the array is valid, false else.
+ */
+ public static function isValidMetadata($meta) {
+ $valid_chars = array('_');
+ return !(empty($meta['name']) ||
+ empty($meta['entrypoint']) ||
+ !ctype_alnum(str_replace($valid_chars, '', $meta['entrypoint'])));
+ }
+
+ /**
+ * Load the extension source code based on info metadata.
+ *
+ * @param $info an array containing information about extension.
+ * @return an extension inheriting from Minz_Extension.
+ */
+ public static function load($info) {
+ $entry_point_filename = $info['path'] . '/' . self::$ext_entry_point;
+ $ext_class_name = $info['entrypoint'] . 'Extension';
+
+ include_once($entry_point_filename);
+
+ // Test if the given extension class exists.
+ if (!class_exists($ext_class_name)) {
+ Minz_Log::warning('`' . $ext_class_name .
+ '` cannot be found in `' . $entry_point_filename . '`');
+ return null;
+ }
+
+ // Try to load the class.
+ $extension = null;
+ try {
+ $extension = new $ext_class_name($info);
+ } catch (Minz_ExtensionException $e) {
+ // We cannot load the extension? Invalid!
+ Minz_Log::warning('In `' . $metadata_filename . '`: ' . $e->getMessage());
+ return null;
+ }
+
+ // Test if class is correct.
+ if (!($extension instanceof Minz_Extension)) {
+ Minz_Log::warning('`' . $ext_class_name .
+ '` is not an instance of `Minz_Extension`');
+ return null;
+ }
+
+ return $extension;
+ }
+
+ /**
+ * Add the extension to the list of the known extensions ($ext_list).
+ *
+ * If the extension is present in $ext_auto_enabled and if its type is "system",
+ * it will be enabled in the same time.
+ *
+ * @param $ext a valid extension.
+ */
+ public static function register($ext) {
+ $name = $ext->getName();
+ self::$ext_list[$name] = $ext;
+
+ if ($ext->getType() === 'system' &&
+ in_array($name, self::$ext_auto_enabled)) {
+ self::enable($ext->getName());
+ }
+
+ self::$ext_to_hooks[$name] = array();
+ }
+
+ /**
+ * Enable an extension so it will be called when necessary.
+ *
+ * The extension init() method will be called.
+ *
+ * @param $ext_name is the name of a valid extension present in $ext_list.
+ */
+ public static function enable($ext_name) {
+ if (isset(self::$ext_list[$ext_name])) {
+ $ext = self::$ext_list[$ext_name];
+ self::$ext_list_enabled[$ext_name] = $ext;
+ $ext->enable();
+ $ext->init();
+ }
+ }
+
+ /**
+ * Enable a list of extensions.
+ *
+ * @param $ext_list the names of extensions we want to load.
+ */
+ public static function enableByList($ext_list) {
+ foreach ($ext_list as $ext_name) {
+ self::enable($ext_name);
+ }
+ }
+
+ /**
+ * Return a list of extensions.
+ *
+ * @param $only_enabled if true returns only the enabled extensions (false by default).
+ * @return an array of extensions.
+ */
+ public static function listExtensions($only_enabled = false) {
+ if ($only_enabled) {
+ return self::$ext_list_enabled;
+ } else {
+ return self::$ext_list;
+ }
+ }
+
+ /**
+ * Return an extension by its name.
+ *
+ * @param $ext_name the name of the extension.
+ * @return the corresponding extension or null if it doesn't exist.
+ */
+ public static function findExtension($ext_name) {
+ if (!isset(self::$ext_list[$ext_name])) {
+ return null;
+ }
+
+ return self::$ext_list[$ext_name];
+ }
+
+ /**
+ * Add a hook function to a given hook.
+ *
+ * The hook name must be a valid one. For the valid list, see self::$hook_list
+ * array keys.
+ *
+ * @param $hook_name the hook name (must exist).
+ * @param $hook_function the function name to call (must be callable).
+ * @param $ext the extension which register the hook.
+ */
+ public static function addHook($hook_name, $hook_function, $ext) {
+ if (isset(self::$hook_list[$hook_name]) && is_callable($hook_function)) {
+ self::$hook_list[$hook_name]['list'][] = $hook_function;
+ self::$ext_to_hooks[$ext->getName()][] = $hook_name;
+ }
+ }
+
+ /**
+ * Call functions related to a given hook.
+ *
+ * The hook name must be a valid one. For the valid list, see self::$hook_list
+ * array keys.
+ *
+ * @param $hook_name the hook to call.
+ * @param additionnal parameters (for signature, please see self::$hook_list).
+ * @return the final result of the called hook.
+ */
+ public static function callHook($hook_name) {
+ if (!isset(self::$hook_list[$hook_name])) {
+ return;
+ }
+
+ $signature = self::$hook_list[$hook_name]['signature'];
+ $signature = 'self::call' . $signature;
+ $args = func_get_args();
+
+ return call_user_func_array($signature, $args);
+ }
+
+ /**
+ * Call a hook which takes one argument and return a result.
+ *
+ * The result is chained between the extension, for instance, first extension
+ * hook will receive the initial argument and return a result which will be
+ * passed as an argument to the next extension hook and so on.
+ *
+ * If a hook return a null value, the method is stopped and return null.
+ *
+ * @param $hook_name is the hook to call.
+ * @param $arg is the argument to pass to the first extension hook.
+ * @return the final chained result of the hooks. If nothing is changed,
+ * the initial argument is returned.
+ */
+ private static function callOneToOne($hook_name, $arg) {
+ $result = $arg;
+ foreach (self::$hook_list[$hook_name]['list'] as $function) {
+ $result = call_user_func($function, $arg);
+
+ if (is_null($result)) {
+ break;
+ }
+
+ $arg = $result;
+ }
+ return $result;
+ }
+
+ /**
+ * Call a hook which takes no argument and returns nothing.
+ *
+ * This case is simpler than callOneToOne because hooks are called one by
+ * one, without any consideration of argument nor result.
+ *
+ * @param $hook_name is the hook to call.
+ */
+ private static function callNoneToNone($hook_name) {
+ foreach (self::$hook_list[$hook_name]['list'] as $function) {
+ call_user_func($function);
+ }
+ }
+}