avoid HTTP image screenshot urls. closes #595

lib/plugins/extension/helper/list.php

@@ -188,10 +188,17 @@ class helper_plugin_extension_list extends DokuWiki_Plugin {
      * @return string The HTML code
      */
     function make_screenshot(helper_plugin_extension_extension $extension) {
-        if($extension->getScreenshotURL()) {
+        $screen = $extension->getScreenshotURL();
+        $thumb = $extension->getThumbnailURL();
+
+        if($screen) {
+            // use protocol independent URLs for images coming from us #595
+            $screen = str_replace('http://www.dokuwiki.org', '//www.dokuwiki.org', $screen);
+            $thumb = str_replace('http://www.dokuwiki.org', '//www.dokuwiki.org', $thumb);
+
             $title = sprintf($this->getLang('screenshot'), hsc($extension->getDisplayName()));
-            $img = '<a href="'.hsc($extension->getScreenshotURL()).'" target="_blank" class="extension_screenshot">'.
-                '<img alt="'.$title.'" width="120" height="70" src="'.hsc($extension->getThumbnailURL()).'" />'.
+            $img = '<a href="'.hsc($screen).'" target="_blank" class="extension_screenshot">'.
+                '<img alt="'.$title.'" width="120" height="70" src="'.hsc($thumb).'" />'.
                 '</a>';
         } elseif($extension->isTemplate()) {
             $img = '<img alt="" width="120" height="70" src="'.DOKU_BASE.'lib/plugins/extension/images/template.png" />';