How to get a custom query running in Wordpress?

I'm trying to get a Page to display a custom query using the snippet posted here. The followin开发者_如何学运维g is in my functions.php:

function alter_the_query($request) {
    $dummy_query = new WP_Query();
    $dummy_query->parse_query($request);
    // this is the actual manipulation
    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?

I suppose this happens because you didn't change $request['pagename'] value, so wp try to load content for this pages.

Update this should work for you

function alter_the_query($request) {
    $dummy_query = new WP_Query();
    $dummy_query->parse_query($request);
    // this is the actual manipulation
    if($dummy_query->is_page('blog')) {
      $request['category_name'] = 'Blog';
      unset($request['pagename']);
    }
    // and then
    return $request;
}