How to make the 'request' filter work?

Question

I'm trying to get a Page to display a custom query using the snippet posted here. The following is in my functions.php:

function alter_the_query($request) {
    $dummy_query = new WP_Query();  // the query isn't run if we don't pass any query vars
    $dummy_query->parse_query($request);
    // this is the actual manipulation; do whatever you need here
    if($dummy_query->is_page('blog')) $request['category_name'] = 'Blog';
    // and then
    return $request;
}
add_filter('request','alter_the_query');

The page called "Blog" has a basic loop inside- so it should be displaying whatever WP_Query tells it to. However, it is only displaying the Page content- which should have been ignored.

I can't seem to find a reference that explains the properties of the $request object, so I'm not sure what I should do to make this snippet work. Any ideas?

Answer 1

Inside your function, simply do a var_dump of the $request object to reveal its properties.