WebDAV support: WebDAV support would allow swift users to mount public containers as network drives in any modern operating system. It could probably be implemented as WSGI middleware, and would therefore be an optional feature for any swift deployment.
Auto-compression: I would like to see swift support dynamic compression and decompression of responses based on the Accept header in the request. This feature too could be implemented as WSGI middleware and be optional for any swift deployment. One concern, however, is the extra CPU cycles required for the compression and decompression. The swift proxy servers can see high CPU load under heavy traffic conditions.
Object versioning: A more complicated feature, object versioning would allow old objects to be accessed after newer data has overwritten them. New semantics for accessing old versions (or even enabling/disabling this feature) would have to be created, and many questions relating to failure scenarios would need to be answered.
stop_marker query parameter in listings: Currently, account and container GETs can be filtered with a marker query parameter. The marker parameter will cause the listing to return values that are greater than the marker. In a container of 100 items a marker equal to item 50 will return items 51 through 100. However, if one wants to only fetch items less than item 60, the listing has to be filtered by the client. A stop_marker query parameter would return anything less than or equal to the parameter value and would be able to be used in conjunction with the other query parameters. This would be a relatively simple feature to add without any obvious (to me) risks to the system as a whole. Update: This feature is now supported in swift: https://code.launchpad.net/~notmyname/swift/end_marker.
If anyone would like to add any of these features to swift, please grab the code and submit your patch.
This work is licensed under a Creative Commons Attribution 3.0 Unported License.
The thoughts expressed here are my own and do not necessarily represent those of my employer.