Get Permalink on Custom Post Type Archive or Taxonomy pages

On a single post or singular page, you get the permalink like:

the_permalink(); // this echoes
// or 
get_permalink(); // this returns, not echo

Get the permalink for a custom post type archives page:

get_post_type_archive_link( get_query_var('post_type') );

Get the permalink for a custom taxonomy page:

get_term_link( get_query_var( 'term' ), get_query_var( 'taxonomy' ) );

Usage

If you use social media open graph tags, then you’ll recognize this which takes the permalink of any current page:

<meta property="og:url" content="<?php the_permalink(); ?>" />

This will not work for WordPress archive pages. But sometimes, especially when using WordPress as a CMS, we have a need to treat an archive page like a regular page, and we want it to get recognized as a page with a permalink. In those cases, I use this to make sure that the correct URL gets inserted into the og:url tag, whether it’s a single post, page, custom taxonomy archive, or custom post type archive.

<?php 
// instead of permalink:
if ( is_tax() ) { 
	$permalink = get_term_link( get_query_var( 'term' ), get_query_var( 'taxonomy' ) );
}
elseif( is_post_type_archive() ) {
	$permalink = get_post_type_archive_link( get_query_var('post_type') );
}
else {
	$permalink = get_permalink();
}
?>
<meta property="og:url" content="<?php echo $permalink; ?>" />