Generate multiple goo.gl shortlinks for qtranslate bilingual blog

So I’ve managed to solve this. The googl_shortlink function from above now looks like this:

function googl_shortlink($url, $post_id = false) {
    global $post;
    if (!$post_id && $post) $post_id = $post->ID;
    elseif ($post_id) $post = get_post($post_id);
    // list all the active languages in an array 
    $enabled_languages = get_option('qtranslate_enabled_languages');

    if (is_404())
        return;

    if ($post && $post->post_status != 'publish')
        return "";

    // go through each active language, get the properly formatted permalink,
    // shorten it with goo.gl, then add it as a post_meta
    foreach ($enabled_languages as $lid=>$lang) {
        if ((is_singular() || $post) && !is_front_page() && qtrans_isAvailableIn($post_id,$lang)) {
            $shortlink = get_post_meta($post_id, '_googl_'.$lang.'_shortlink', true);
            if ($shortlink)
                return $shortlink;

            // the last parameter here was the major headache. It's called $forceadmin and defaults
            // to false (by default it doesn't prepend language-specific path to links generate in /wp-admin)
            $permalink = qtrans_convertURL(get_permalink($post_id),$lang,true);
            $shortlink = googl_shorten($permalink); // shorten the url. No changes done here

            if ($shortlink !== $url) {
                add_post_meta($post_id, '_googl_'.$lang.'_shortlink', $shortlink, true);
            } else {
                add_post_meta($post_id, '_googl_'.$lang.'_shortlink', $url, true);
            }
        }
    }
}

Trigger on save:

function googl_save_post($post_ID, $post) {
    // Don't act on auto drafts.
    if ($post->post_status == 'auto-draft')
        return;
    $enabled_languages = get_option('qtranslate_enabled_languages');
    foreach ($enabled_languages as $lid=>$lang)
        delete_post_meta($post_ID, '_googl_'.$lang.'_shortlink');
}
add_action('save_post', 'googl_save_post', 10, 2);

And show up in dashboard:

function googl_post_columns($columns) {
    $columns['shortlink'] = 'Shortlink';
    return $columns;    
}

function googl_custom_columns($column) {
    global $post;

    if ('shortlink' == $column) {
        $enabled_languages = get_option('qtranslate_enabled_languages');
        foreach ($enabled_languages as $lid=>$lang) {
            if (qtrans_isAvailableIn($post->ID,$lang)) {
                $shorturl = get_post_meta($post->ID, '_googl_'.$lang.'_shortlink', true);
                $shorturl_caption = str_replace('http://', '', $shorturl);
                $shorturl_info = str_replace('goo.gl/', 'goo.gl/info/', $shorturl);
                echo "$lang: <a href="https://wordpress.stackexchange.com/questions/53401/{$shorturl}">{$shorturl_caption}</a> (<a href="{$shorturl_info}">info</a>)<br />";
            }
        }
    }
}
add_action('manage_posts_custom_column', 'googl_custom_columns');
add_filter('manage_edit-post_columns', 'googl_post_columns');

Drawbacks

I was unable to make wp_get_shortlink() to work with the new shortlink schema. The above googl_shortlink doesn’t return anything, since that would make the foreach loop bail out after processing the first language. Quick replacement (could be easily wrapped in a function to make it more friendly):

// can be used anywhere in the loop to get the 
// shortlink for a specific post and language
get_post_meta($post->ID, '_googl_'.qtrans_getLanguage().'_shortlink', true);

Same thing goes for wp_shortlink_wp_head() (since it calls on wp_get_shortlink):

function googl_shortlink_wp_head() {
    global $post;
    $shortlink = get_post_meta($post->ID, '_googl_'.qtrans_getLanguage().'_shortlink', true);

    if (empty($shortlink))
        return;

    echo "<link rel="shortlink" href="".esc_url($shortlink)."" />\n";
}
// out with the old, in with the new
remove_action('wp_head','wp_shortlink_wp_head',10,0);
add_action('wp_head','googl_shortlink_wp_head',10,0);

Credits

Kudos goes to Konstantin Kovshenin for the simple, yet effective googl plugin.