Add enable / disable extension features

See https://github.com/FreshRSS/FreshRSS/issues/252

app/Controllers/extensionController.php

@@ -29,12 +29,80 @@ class FreshRSS_extension_Controller extends Minz_ActionController {
 		}
 	}
 
+	/**
+	 * This action enables a disabled extension for the current user.
+	 *
+	 * System extensions can only be enabled by an administrator.
+	 *
+	 * Parameter is:
+	 * - e: the extension name (urlencoded).
+	 */
 	public function enableAction() {
-		
+		$url_redirect = array('c' => 'extension', 'a' => 'index');
+
+		if (Minz_Request::isPost()) {
+			$ext_name = urldecode(Minz_Request::param('e'));
+			$ext = Minz_ExtensionManager::find_extension($ext_name);
+
+			if (is_null($ext)) {
+				Minz_Request::bad('feedback.extension.not_found', $url_redirect);
+			}
+
+			if ($ext->is_enabled()) {
+				Minz_Request::bad('feedback.extension.already_enabled', $url_redirect);
+			}
+
+			if ($ext->getType() === 'system' && !FreshRSS_Auth::hasAccess('admin')) {
+				Minz_Request::bad('feedback.extension.no_access', $url_redirect);
+			}
+
+			$ext->install();
+
+			FreshRSS_Context::$conf->addExtension($ext_name);
+			FreshRSS_Context::$conf->save();
+
+			Minz_Request::good('feedback.extension.enabled', $url_redirect);
+		}
+
+		Minz_Request::forward($url_redirect, true);
 	}
 
+	/**
+	 * This action disables an enabled extension for the current user.
+	 *
+	 * System extensions can only be disabled by an administrator.
+	 *
+	 * Parameter is:
+	 * - e: the extension name (urlencoded).
+	 */
 	public function disableAction() {
-		
+		$url_redirect = array('c' => 'extension', 'a' => 'index');
+
+		if (Minz_Request::isPost()) {
+			$ext_name = urldecode(Minz_Request::param('e'));
+			$ext = Minz_ExtensionManager::find_extension($ext_name);
+
+			if (is_null($ext)) {
+				Minz_Request::bad('feedback.extension.not_found', $url_redirect);
+			}
+
+			if (!$ext->is_enabled()) {
+				Minz_Request::bad('feedback.extension.not_enabled', $url_redirect);
+			}
+
+			if ($ext->getType() === 'system' && !FreshRSS_Auth::hasAccess('admin')) {
+				Minz_Request::bad('feedback.extension.no_access', $url_redirect);
+			}
+
+			$ext->uninstall();
+
+			FreshRSS_Context::$conf->removeExtension($ext_name);
+			FreshRSS_Context::$conf->save();
+
+			Minz_Request::good('feedback.extension.disabled', $url_redirect);
+		}
+
+		Minz_Request::forward($url_redirect, true);
 	}
 
 	public function removeAction() {

app/Models/Configuration.php

@@ -350,4 +350,16 @@ class FreshRSS_Configuration {
 		}
 		$this->data['extensions_enabled'] = $value;
 	}
+	public function removeExtension($ext_name) {
+		$this->data['extensions_enabled'] = array_diff(
+			$this->data['extensions_enabled'],
+			array($ext_name)
+		);
+	}
+	public function addExtension($ext_name) {
+		$found = array_search($ext_name, $this->data['extensions_enabled']) !== false;
+		if (!$found) {
+			$this->data['extensions_enabled'][] = $ext_name;
+		}
+	}
 }

lib/Minz/ExtensionManager.php

@@ -160,10 +160,8 @@ class Minz_ExtensionManager {
 		}
 	}
 
-
-
 	/**
-	 * Returns a list of extensions.
+	 * Return a list of extensions.
 	 *
 	 * @param $only_enabled if true returns only the enabled extensions (false by default).
 	 * @return an array of extensions.
@@ -175,4 +173,18 @@ class Minz_ExtensionManager {
 			return self::$ext_list;
 		}
 	}
+
+	/**
+	 * Return an extension by its name.
+	 *
+	 * @param $ext_name the name of the extension.
+	 * @return the corresponding extension or null if it doesn't exist.
+	 */
+	public static function find_extension($ext_name) {
+		if (!isset(self::$ext_list[$ext_name])) {
+			return null;
+		}
+
+		return self::$ext_list[$ext_name];
+	}
 }