Framework for Enhancing Mobile Availability of RESTful Services

Providing users of mobile devices uninterrupted access to web services in unstable network conditions continues to be a problem. Numerous methods for service caching have been proposed; however, most studies fail to consider two crucial factors: (1) Context of network connectivity: Smartphones are used in a variety of wireless network conditions, such as high-speed networks, unstable networks, and areas without an available network connection; and (2) Service failure handling: Current service caching mechanisms are able to deal with temporary unavailability, but they cannot handle long-time service failures or malfunctions. This paper proposes a connectivity-aware, risk-driven (CARD) approach to the delivery of RESTful services. The CARD approach is encapsulated in the form of a client-side library for use by mobile applications (apps) to invoke backend RESTful services in a highly-available manner. The CARD approach has two main features: 1) the ability to perform actions specific to the network conditions, such as the application of prefetch services and caching services when connected to high speed wireless networks to ensure that cached services are used for unstable wireless networks, and allowing users to request cached service responses from other users when no wireless network can be accessed. 2) The proposed risk-driven analysis method enables the provision of a reasonable service recovery plan when the original service malfunctions. Experiments demonstrate that the proposed CARD approach expands the availability of service and shortens service response times under a variety of network conditions.