Golang + MongoDB + Memcached backend for the jQuery File Upload plugin.
All interaction with MongoDB is done thru a simple interface, so adding support for other datastores should be pretty easy.
See pkgdoc for automatic documentation.
See jfu-example for a simple demo app.
Released under the WTFPL v2.
Derived from Sebastian Tschan's MIT-licensed example code, included with the jQuery File Upload plugin, for a Google AppEngine-based Go backend.