Cofocus: REST Framework for Collaborative Endpoint Network in Mobile Environment

In this paper, we present an approach to enable collaborative endpoint network for mobile phones and devices. In particular, we expose functions on mobile phones as REST web services and make mobile phones as web service providers for rapid integration with communication and collaboration applications. To accommodate the distinct features and constraints in mobile environment, this paper describes a lightweight and efficient protocol, Compact HTTP, which consists of a small subset of HTTP 1.1 to reduce the footprint of REST services. We expand bindings of HTTP to multiple messaging protocols, including XMPP, and make the REST services invariant to network and protocol changes. These expanded bindings introduce asynchrony into REST, a desired property for communication and collaboration services. Furthermore, HTTP over XMPP described in our approach introduces the concept of hyperlink presence in collaboration, and it is used to mitigate the broken link issue which is acute in mobile environments as devices and resources can come and go in an unpredictable pattern. To provide end-to-end message security, a symmetric key based security scheme is described for service authentication and authorization. A prototype system based on the proposed approach is developed that allows both local operators and remote directors to control and monitor resources in a secure manner on Android phones and devices, e.g. camera, camcorder, audio, location, telephony, motion, power, etc. Experimental results indicate that the proposed approach is feasible, lightweight, and has satisfactory performance.