SOLVED Dynamic (fake) pages and $language

[fripsy]

Finally I got this sorted out !
I post the solution here in case anyone is strugling with something similar.

Problem:
Display the correct language for pages created by a plugin through the "data-index", "indexid" and "menuitems" filters.

First, make sure you have seperate translation files for front- and backend.

• Backend: en_US.php, fr_FR.php, de_DE.php, ...
  
• Frontend: en.php, fr.php, de.php, ...
  

In the top of "my_plugin.php":

PHP Code:

add_filter('menuitems', 'my_menuitems');
add_filter('indexid', 'my_indexid');
add_filter('data_index', 'my_data_index'); 


In the "my_menuitems"-filter function:

PHP Code:

function my_menuitems($menu) {
    global $language;

    if (isset($_COOKIE['language'])) {
        i18n_merge('GSDownloads', $language);
    } else {
        i18n_merge('GSDownloads', 'en');  // set default language
    }

    if ((isset($_GET['id'])) && ($_GET['id'] === 'my_plugin')) {
        $menu .= '<li class="index current active"><a href="' . $SITEURL . 'index.php?id=my_plugin" title="' . i18n_r('my_plugin/MENU') . '">' . i18n_r('my_plugin/MENU') . '</a></li>';
    } else {
        $menu .= '<li class="index"><a href="' . $SITEURL . 'index.php?id=my_plugin" title="' . i18n_r('my_plugin/MENU') . '">' . i18n_r('my_plugin/MENU') . '</a></li>';
    }
    return $menu;
} 


In the "my_indexid"-filter funtion:

PHP Code:

    global $my_plugin_id;  // store id to use later in the "data-index" function

    if ($id === 'my_plugin') {
        $my_plugin_id= $id;
    } else {
        $my_plugin_id= '';
    }
    return $id;
} 


In the "data-index"-filter function:

PHP Code:

function GSDDataIndex($data_index) {
    
    global $my_plugin_id, $language;
    
    if ($my_plugin_id === 'my_plugin') {

        i18n_init();
        if (isset($_GET[I18N_SET_LANGUAGE_PARAM])) {
            $language = $_GET[I18N_SET_LANGUAGE_PARAM];
            i18n_merge('my_plugin', $language);
        } else {
            if (isset($_COOKIE[I18N_LANGUAGE_COOKIE])) {
                $language = $_COOKIE[I18N_LANGUAGE_COOKIE];
                i18n_merge('my_plugin', $language);
            } else {
                i18n_merge('my_plugin', 'en');
            }
        }

        $data_index = new SimpleXmlElement('<?xml version="1.0" encoding="UTF-8"?>' . "\n" . '<item></item>');
        $data_index->addChild('title', i18n_r('my_plugin/TITLE'));
        $data_index->addChild('menu', i18n_r('my_plugin/MENU'));
        $data_index->addChild('pubDate', '');
        $data_index->addChild('meta', '');
        $data_index->addChild('metad', '');
        $data_index->addChild('url', 'my_plugin');
        $data_index->addChild('content', i18n_r('my_plugin/CONTENT'));
        $data_index->addChild('parent', '');
        $data_index->addChild('template', '');
        $data_index->addChild('private', '');    
    }

    return $data_index;
} 


Voilà, that's all folks !

It took me a while to figure this out, I hope it will be of some use to someone.

Cheers,
Fripsy.