Alternate transport for U1DB sync protocol

by Indradhanush Gupta for LEAP Encryption Access Project

HTTP, although an excellent mode of communication is poor for message transfers. It uses persistent connections which unnecessarily hog up network resources for messaging applications like the sync process used by LEAP Encryption Access Project. The implementation uses U1DB, which provides no alternative transport other than HTTP. Thus it's imperative that an alternate transport be used for such applications. Also it should let users select specific documents to sync and recover from a crash.