trouble changing uri to query string

[Roland RoLaNd]

i have a url looking as such:  mysite.com/some/path/rest/v2/giveit.view&user=282&imageid=23&size=80

 i want the cache key to match imageid=23&size=80 without the "user" part.



$args isn't matching because incoming url lacks the "?" part, so $uri is detected as mysite.com/some/path/rest/v2/giveit.view&imageid=23&size=80


Is there a way i could force nginx to detect that query string, or rewrite/set the args on each request ?