Drupal 7 Contextual Filter on URL Alias
I think the simpliest way is to use Panels, and override the Node page. Add a variant and put your view in it, and send the node's nid argument to it, using node:nid contextual argument.


(install page manager)
Enable node view page (node/%node)
Add a variant, set a validation criteria selecting your concerned node type
Use simple one-column display
Add your view in your column
It asks for an argument, send the node:nid, (or entity_id, or whatever)
In your view, use node:nid contextual filter


All is done.