I had a great discussion today with Frank McPherson about OPML, OPML includes, my OPML Includes test app, and our joint experiment in using drummer.this.how to show included files. We agreed that to view updates in drummer.this.how for an OPML file that includes another OPML file, the master OPML file has to be opened in Drummer and refreshed to see updates. In my test app, when a user goes to the app URL, they will get the latest updates for all included files. This will also occur each time the test app is refreshed in the browser.
Another subject we discussed was how a user could know if updates had been made to one of the OPML files. The JSON object for the included OPML files contains the lastModified element from the head of the OPML file, so this date/time could be displayed like in the drummer.this.how app for any or all of the included OPML files. Frank wrote about having each top-level headline as an item in a RSS feed (one way to provide notification of changes). I could envision an app that could look at changes in an OPML file and create some kind of item using the namespace feature in RSS. It is an area worth exploring.
I also spent some time today looking at Dave Winer’s update to the outlineBrowser toolkit. I downloaded his personal site repo and set up a test site using my Oregon elections OPML file, and the rendering/navigation looked good. I am going to work on trying to incorporate these latest changes into my OPML Includes test app.