Looks good Andy. Theres a bit of white space. Try squash it on commit. You don't have a test of the new facility. Would that be hard to add?
[rest] content transcoding
Review Request #1136 - Created Oct. 29, 2010 and submitted
Introduce a table schema attribute for column families that instructs the REST gateway to perform input and/or output transcoding, with base64->binary (for GET) and vice versa (for PUT or POST) as the first supported option.
Created a test table. Modified the HCD of a column family by adding a custom attribute of 'Transform$1' => '*:Base64'. Used curl to store the string "Testing 1, 2, 3" using content type application/octet-stream. Confirmed with shell the value was base64 encoded in table. Used curl to retrieve the value using accept header of application/octet-stream and confirmed the response body was the decoded string.