Yesterday, musing about traversing my social graph through blogrolls, I suggested using OPML’s include attribute as a way of adding the blogrolls of the blogs I follow in my own blogroll. Ideally using a spec compliant OPML reader, you’d be able to seamlessly navigate from my blogroll, through the blogroll of one of the blogs I follow, to the blogroll of someone they follow, and presumably back to me at some point.
It does require having an OPML version of such blogrolls available. Peter publishes his blogroll as OPML as I do, allowing a first simple experiment: do includes get correctly parsed in some of the Outliner tools I have?
Adding an include into my OPML file
This little experiment starts with adding to my list of RSS feeds I follow a reference to Peter’s own OPML file of feeds he follows. I already follow two of Peter’s RSS feeds (blogposts and favourites) which I now placed in their own subfolder and to which I added an outline node of the include type, with the URL of Peter’s OPML file.
Screenshot of my OPML file listing the RSS feeds I follow. Click to enlarge. On line 22 you see the line that includes Peter’s OPML file by mentioning its URL.
Trying three outliners
Cloud Outliner (which I in the past used to first create outlines that could then be sent to Evernote) does not parse OPML includes correctly upon import. It also doesn’t maintain any additional attributes from OPML outline nodes, just the text attribute.
Screenshot of Cloud Outliner showing incorrect import of my OPML file. Click to enlarge.
Tinderbox like Cloud Outliner fails to load OPML includes as per spec. It does load some of the attributes (web url, and description, next to the standard text attribute), but not any others (such as the feed url for instance, the crucial element in a list of RSS feeds). It looks like it only picks up on attributes that are directly mappable on pre-existing default attributes within Tinderbox itself.
Screenshot of how Tinderbox imports my OPML file. It keeps some attributes but ignores most, and for includes just mentions the URL
Electric Drummer does correctly import the entire OPML outline. As Dave Winer is both the original creator of the OPML specification and more recently of the Electric Drummer app, this is consistent. Electric Drummer picks up on all attributes in an imported OPML file. Upon import it also fetches the external OPML files listed as includes from their URLs, and fully incorporates them into the imported outline.
Screenshot of Drummer, which incorporates the content of Peter’s OPML file I linked to in my OPML file. Click to enlarge.
Opening up options for tinkering
So at least there is 1 general outliner tool that can work with includes. It probably also means that Dave’s OPML package can do the same, which allows me to tinker at script level with this. One candidate for tinkering is, where a blogger has a blogroll, just not in OPML, to use the OPML package to convert scraped HTML to OPML, and include it locally. That allows me to traverse sets of blogrolls and see the overlap, closed triangles, feedback loops etc. I could also extend my own published blogroll by referencing all the published blogrolls of the bloggers I follow. For you my blogroll would then support exploration and discovery one step further outwards in the network. In parallel I can do something similar for federated bookshelves (both in terms of books as in terms of lists of people who’s booklists and their lists of people you follow)