Add skeleton of the plugin architecture

By Leonardo Sapiras, reviewed, integrated, commited by ioguix.

classes/Plugin.php

@@ -0,0 +1,36 @@
+<?php
+abstract class Plugin {
+
+	/**
+	 * Constructor
+	 * Register the plugin's functions in hooks of PPA.
+	 * @param $language Current phpPgAdmin language.
+	 */
+	function __construct($language) {
+		// Set the plugin's language
+		$plugin_directory = "plugins/". $this->get_name();
+		require_once("{$plugin_directory}/lang/recoded/english.php");
+		if (file_exists("{$plugin_directory}/lang/recoded/{$language}.php")) {
+			include_once("{$plugin_directory}/lang/recoded/{$language}.php");
+		}
+		$this->lang = $plugin_lang;
+
+		if (file_exists("{$plugin_directory}/conf/config.inc.php")) {
+			include_once("{$plugin_directory}/conf/config.inc.php");
+			$this->conf = $plugin_conf;
+		}
+	}
+
+	abstract function get_hooks();
+
+	abstract function get_actions();
+
+	/**
+	 * Get the plugin name, that will be used as identification
+	 * @return $name
+	 */
+	function get_name() {
+		return $this->name;
+	}
+}
+?>

classes/PluginManager.php

@@ -0,0 +1,114 @@
+<?php
+
+/**
+ * A class that implements the plugin's system
+ */
+
+class PluginManager {
+
+	/**
+	 * Attributes
+	 */
+	private $plugins_list = array();
+	private $available_hooks = array(/* wip, will be added in next commits */);
+	private $actions = array();
+	private $hooks = array();
+
+	/**
+	 * Register the plugins
+	 * @param $language - Language that have been used.
+	 */
+	function __construct($language) {
+		global $conf, $lang;
+
+		// Get the activated plugins
+		$plugins = $conf['plugins'];
+
+		foreach ($plugins as $activated_plugin) {
+			$plugin_file = './plugins/'.$activated_plugin.'/plugin.php';
+
+			// Verify is the activated plugin exists
+			if (file_exists($plugin_file)) {
+				include_once($plugin_file);
+				$plugin = new $activated_plugin($language);
+				$this->add_plugin($plugin);
+			} else {
+				printf($lang['strpluginnotfound']."\t\n", $activated_plugin);
+				exit;
+			}
+		}
+	}
+
+	/**
+	 * Add a plugin in the list of plugins to manage
+	 * @param $plugin - Instance from plugin
+	 */
+	function add_plugin($plugin) {
+		global $lang;
+
+		//The $plugin_name is the identification of the plugin.
+		//Example: PluginExample is the identification for PluginExample
+		//It will be used to get a specific plugin from the plugins_list.
+		$plugin_name = $plugin->get_name();
+		$this->plugins_list[$plugin_name] = $plugin;
+
+		//Register the plugin's functions
+		$hooks = $plugin->get_hooks();
+		foreach ($hooks as $hook => $functions) {
+			if (!in_array($hook, $this->available_hooks)) {
+				printf($lang['strhooknotfound']."\t\n", $hook);
+				exit;
+			}
+			$this->hooks[$hook][$plugin_name] = $functions;
+		}
+
+		//Register the plugin's actions
+		$actions = $plugin->get_actions();
+		$this->actions[$plugin_name] = $actions;
+	}
+
+	/**
+	 * Execute the plugins hook functions when needed.
+	 * @param $hook - The place where the function will be called
+	 * @param $function_args - An array reference with arguments to give to called function
+	 */
+	function do_hook($hook, &$function_args) {
+		if (isset($this->hooks[$hook])) {
+			foreach ($this->hooks[$hook] as $plugin_name => $functions) {
+				$plugin = $this->plugins_list[$plugin_name];
+				foreach ($functions as $function) {
+					if (method_exists($plugin, $function)) {
+						call_user_func(array($plugin, $function), $function_args);
+					}
+				}
+			}
+		}
+	}
+
+	/**
+	 * Execute a plugin's action
+	 * @param $plugin_name - The plugin name.
+	 * @param $action - action that will be executed.
+	 */
+	function do_action($plugin_name, $action) {
+		global $lang;
+
+		if (!isset($this->plugins_list[$plugin_name])) {
+			// Show an error and stop the application
+			printf($lang['strpluginnotfound']."\t\n", $name);
+			exit;
+		}
+		$plugin = $this->plugins_list[$plugin_name];
+
+		// Check if the plugin's method exists and if this method is an declared action.
+		if (method_exists($plugin, $action) and in_array($action, $this->actions[$plugin_name])) {
+			call_user_func(array($plugin, $action));
+		}
+		else {
+			// Show an error and stop the application
+			printf($lang['stractionnotfound']."\t\n", $action, $plugin_name);
+			exit;
+		}
+	}
+}
+?>

conf/config.inc.php-dist

@@ -154,7 +154,17 @@
 	// Configuration for ajax scripts
 	// Time in seconds. If set to 0, refreshing data using ajax will be disabled (locks and activity pages)
 	$conf['ajax_refresh'] = 3;
-
+
+	/** Plugins management
+	 * Add plugin names to the following array to activate them
+	 * Example:
+	 *   $conf['plugins'] = array(
+	 *     'Example',
+	 *     'Slony'
+	 *   );
+	 */
+	$conf['plugins'] = array();
+
 	/*****************************************
 	 * Don't modify anything below this line *
 	 *****************************************/

lang/english.php

@@ -909,4 +909,9 @@
 	$lang['strftstabdicts'] = 'Dictionaries';
 	$lang['strftstabparsers'] = 'Parsers';
 	$lang['strftscantparsercopy'] = 'Can\'t specify both parser and template during text search configuration creation.';
+
+	//Plugins
+	$lang['strpluginnotfound'] = 'Error: plugin \'%s\' not found. Check if this plugin exists in the plugins/ directory, or if this plugins has a plugin.php file. Plugin\'s names are case sensitive';
+	$lang['stractionnotfound'] = 'Error: action \'%s\' not found in the \'%s\' plugin, or it was not specified as an action.';
+	$lang['strhooknotfound'] = 'Error: hook \'%s\' is not avaliable.';
 ?>

libraries/lib.inc.php

@@ -226,4 +226,8 @@ function htmlspecialchars_decode($string, $quote_style = ENT_COMPAT) {
 			return strtr($string, array_flip(get_html_translation_table(HTML_SPECIALCHARS, $quote_style)));
 		}
 	}
+
+	// Manage the plugins
+	require_once('./classes/PluginManager.php');
+	$plugin_manager = new PluginManager($_language);
 ?>

plugin.php

@@ -0,0 +1,5 @@
+<?php
+require_once('./libraries/lib.inc.php');
+
+$plugin_manager->do_action($_REQUEST['plugin'], $_REQUEST['action']);
+?>