DPUB IG Telco, 2016-11-07: Service Workers in Action

See minutes online for a more detailed record of the discussions.

Service Workers in action

Dave Cramer made a short presentation of a proof-of-concept work he has done: a “reader” page that:

• had a number of references to books; each book:
  • is a collection of HTML/CSS etc files
  • has a manifest: a small extension to the Web App Manifest, also containing a list of resources and a “spine”
  • can be displayed via a javascript application bound to the reader page (as opposed to be part of a book) in an iFrame
  • may have book-wide user preferences (eg, night mode)
  • can be stored offline using a Service Worker based functionality
  • can be dumped into a zip file
• the reader page has interaction buttons for ‘next’ and ‘previous’, using the “spine” in the book’s manifest, as well as buttons for the offline storage and dump to zip

The discussion following the presentation concentrated on issues like how one would store, on long term, data like user’s preferences, annotations, etc. The value of having the reader javascript application attached to the reader page, ie, the fact that the “book” itself does not (necessarily) carry javascript was also emphasized.

One specific issue that came up (for future discussion) is whether the fact that that Service Workers rely on HTTPS (as opposed to HTTP) is, for publication, limiting or future looking?

Obviously, this is (at this moment) only a proof-of-concept; the goal is to see if a Service Worker based approach is feasible in the first place. There are other, similar experiments around the same subject, with different design decisions; these should be looked at in the future, too.