Meta Descriptions for dynamic pages

Ok this seems to be the answer to my question, but I am expiriencing problems with the API functionality.

using this function to use a custom meta desc for my dynamic content pages:

function yoastMetadesc($defaultMeta) {
	switch($pagename){
		case "xyz":
			$x = ($wp_query->query_vars["x"]) ? $wp_query->query_vars['x'] : "x";
			switch($x){
				case "y":
					return "123";
				break;
				default:
					return "custom default desc";
			}
		break;
		default:
			return $defaultMeta;
	}
}
add_filter( 'wpseo_metadesc', 'yoastMetadesc', 10, 1 );

My problem now is that my custom meta desc only gets shown on the frontpage. there is no meta desc inside my blog postings or on my dynamic pages 🙁 Only if I enter something manually inside the meta desc box widget inside on the “edit page” page. shouldnt it display the excerpt if I dont enter something manually?

All templates use the same header.php, which calls wp_head(), so this is not the problem.

Can somebody tell me what the problem is? Why isnt the meta desc populating inside my blog postings?

Hmmmm, not sure if this is what I want to achieve…

On articles, I want the articles excerpt to be the meta description (which is the default behavior of this plugin AFAIK). On Pages, it should be the custom meta description, which I want to define via the function posted above.

I now filled the fields you mentioned with default meta descriptions & titles, but they are now shown on every article/page, instead of the excerpt.

What am I missing?

No no, the problem was something different, but I managed to fix it now… I removed the default parameter from the function and used the global $pagename var – now it works.

%%excerpt%%

This one solved my problem for the articles tho – big thanks!