amazonwebservices/aws-sdk-for-php — pull request #25 by edusnet (2012-04-19 07:51:26+00:00)
Title: s3 class  get_object_url method  with PUT method and a specific content-type 

This code fix the issue when you make a get_object_url with PUT method and you want to specify the content-type.

Without this code the url is signed with an empty content-type, so when make a request with a specific content-type header and the signed url that you got, you will get a "signature doesn't match" error in the response.
With this little fix you have a chance to pass a content-type in the $opt array param of get_objet_url method in order to pre-sing the url with a specific content-type.