Scrapp is an Android app developed by Tilman Ginzel, Rahel Habacker and Jonas Theis during our studies at the RheinMain University of Applied Sciences. The development took place in a fifth semester course called Mobile Computing lectured by Prof. Dr. Peter Barth in summer 2015.
The apps purpose is to notify its users about specific content changes on any website via push-notifications. To do so, it simulates a browser which follows a sequence of URLs and extracts the desired content with XPATH or CSS-Queries (web scraping). The content will be hashed and compared to an older state, to check if it has changed.
One major feature is that multiple users can subscribe to a specific Rule (sequence of URLs) and thereby share the effort of regular polling for content changes. The user can configure a time interval, describing the points in time when the app should automatically poll in the background. If new content is found, every subscriber will be notified. A server is used to share this information with other interested users. For security and privacy concerns it is important to mention that only hashes and no content will be shared.
A full description of the process, possible use cases and implementation details can be found in the documentation (pdf, german).
See scrapp-server for the backend implementation.