diff --git a/lib/remote_storage/rest_provider.rb b/lib/remote_storage/rest_provider.rb
index 626e55c..740c053 100644
--- a/lib/remote_storage/rest_provider.rb
+++ b/lib/remote_storage/rest_provider.rb
@@ -118,6 +118,9 @@ module RemoteStorage
     end
 
     def put_data(user, directory, key, data, content_type)
+      # Do not try to perform the PUT request when the Content-Type does not
+      # look like a MIME type
+      server.halt 415 unless content_type.match(/^.+\/.+/i)
       server.halt 400 if server.env["HTTP_CONTENT_RANGE"]
       server.halt 409, "Conflict" if has_name_collision?(user, directory, key)
 
@@ -506,10 +509,5 @@ module RemoteStorage
       items
     end
 
-    def validate_content_type(content_type)
-      # Do not try to perform the PUT request when the Content-Type does not
-      # look like a MIME type
-      server.halt 415 unless content_type.match(/^.+\/.+/i)
-    end
   end
 end
diff --git a/lib/remote_storage/s3.rb b/lib/remote_storage/s3.rb
index ff6ac59..c852006 100644
--- a/lib/remote_storage/s3.rb
+++ b/lib/remote_storage/s3.rb
@@ -16,8 +16,6 @@ module RemoteStorage
     end
 
     def do_put_request(url, data, content_type)
-      validate_content_type(content_type)
-
       deal_with_unauthorized_requests do
         md5 = Digest::MD5.base64digest(data)
         authorization_headers = authorization_headers_for(