Crow API: Cross-device I/O Sharing in Web Applications

Although cross-device input/output (I/O) sharing is useful for users who own multiple computing devices, previous solutions had a platform-dependency problem. The meta-platform characteristics of web applications could provide a viable solution. In this paper, we propose the Crow application programming interface (API) that allows web applications to access other devices' I/O through standard web APIs without modifying operating systems or browsers. The provision of cross-device I/O should resolve two key challenges. First, the web environment lacks support for device discovery when making a device-to-device connection. This requires a significant effort for developers to implement and maintain signaling servers. To address this challenge, we propose a serverless Crow connectivity mechanism using devices' I/O-specific communication schemes. Second, JavaScript runtimes have limitations in supporting cross-device inter-process communication (IPC). To solve the problem, we propose a web IPC scheme, called Crow IPC, which introduces a proxy interface that relays the cross-device IPC connection. Crow IPC also provides a mechanism for ensuring functional consistency. We implemented the Crow API as a JavaScript library with which developers can easily develop their applications. An extensive evaluation showed that the Crow API provides cross-device I/O sharing functionality effectively and efficiently on various web applications and platforms.