BSG21

Thanks for that. Just wanted to make sure. Been doing a lot of auditing lately and that jumped out at me.

Duplicate

Awesome, that works perfectly. Thank you!

This code will do it:

global $wp_query;
 $attachment_page_id = $wp_query->post->ID;
 $parent_post = get_post($attachment_page_id);
 $parent_post_id = $parent_post->post_parent;

 $parent_post_permalink = get_permalink($parent_post_id);

Alright, I got it to work but it is outputting the canonical <link > tag twice.

This is the code I used I just need to know what extra step(s) I need to take to keep it from duplicating

function attachment_wpseo_canonical ($can) {
 global $wp_query;
 $attachment_page_id = $wp_query->post->ID;
 $parent_post = get_post($attachment_page_id);
 $parent_post_id = $parent_post->post_parent;

 $parent_post_permalink = get_permalink($parent_post_id);
 echo "<link rel=\"canonical\" href=\"$parent_post_permalink\" />";
 }
 add_filter('wpseo_canonical','attachment_wpseo_canonical');

Thanks for the response. How do I get the post url that the attachment is assigned to outside the loop since I will need to do this before the loop.