How can I change a SEF URL to display another template?

Question

I am using Joomla 3.3 and K2 v2.6.9.

I have a category view with several items, namely books. The URL looks like this:

http://localhost/index.php?option=com_k2&view=itemlist&task=category&id=214:publikationen&Itemid=203

To present these items in a CSV-style list, I need to use another template, called csv-view. So I create the link to this view by this code::

<?php echo $_SERVER['REQUEST_URI']; ?>&amp;template=csv-view

resulting in this URL:

http://localhost/index.php?option=com_k2&view=itemlist&task=category&id=214:publikationen&Itemid=203&template=csv-view

This works.

But when I activate SEF URL the URL changes to

http://localhost/navigation/forschung/itemlist/category/214-publikationen.html

and the extended URL would be

http://localhost/navigation/forschung/itemlist/category/214-publikationen.html&template=csv-view

and this page can't be found.

So here is my question: how can I construct the correct URL for the CSV view even if SEF URLs are activated?

Answer 1

1. Instead of $_SERVER['REQUEST_URI'], you can rely on JUri::root()

2. template parameter can not be added concatenating it with &. It has to be ? ... but it depends on the Url query. Thus, you need a piece of code like this to define the glue:

   $uri = JUri::getInstance($url);
   $query = $uri->getQuery();
   
   if (empty($query))
   {
       $glue = '?';
   }
   else
   {
       $glue = '&';
   }
   

As suggested by @fruppel in a more compact way:

    $uri = JUri::getInstance($url); 
    $uri->setVar('tmpl', 'csv-view'); 
    $url = $uri->toString();