Archive for the 'OPML' Category

Interesting ideas in OPML 2.0 spec

Tuesday, August 28th, 2007

Dave Winer is working on the next version of the OPML specification, and there are a number of features it adds that I’d like us to support in Grazr. The one that opens the most possibilites is the idea of using OPML within an RSS feed. This means that you can now create a series of posts that are each outlines. Dave uses the example of podcast show notes, but there are lots of other applications as well. You could use it to deliver an ongoing series of transcripts of conversations, or to present a continuing set of data about a rapidly changing event, such as a hostage drama, or a natural disaster. There was just a small quake in the Bay area. Right now the USGS delivers continuous updates on earthquakes through a feed. What if instead of just a link or a few data points in the body of each item, they could deliver an outline with a complete sequence of siesmic data within each feed item? This presents all types of applications for delivery of scientific data within feeds that requires time series data to describe each event.

The other useful addition to the spec is more details on the category attribute. This allows for better integration of tags into OPML nodes. I can also see how this could be applied to a social graph, by allowing you to describe a hierarchy of relationships. I first got interested in OPML as a way of annotating data about feeds. It was a useful way of adding meta data. The category attribute is a good enhancement to that use case.

In general I think that we’ll be able to incorporate all the additions Dave has made, and I can’t see anything that will break our existing widgets, so we’ll have no problem supporting the new spec.

Common OPML errors

Monday, July 16th, 2007

We are adding an OPML validator to Grazr that can report the most common errors. We need this to make sure that files are valid when they are uploaded. We also need to validate files after they are edited with any of the OPML editing tools we are working on. This validation will be built into the site, but we may also create a free-standing validator.grazr.com that anyone can use to test an OPML URL.

We get to see a lot of funky OPML, such as nodes that have one of the possible URL attributes, but no type attribute. So what is the creator’s intention? Is it a link, a feed, or an include? Do we just guess? It would be better if we can warn people, and they can go back and create a more valid file. With that in mind, here is our current list of the most common ways people go wrong with OPML.

  • Files must have <opml version=”[number]” [optional namespace]> tag as line 2.   
  • Files must have a <head></head> section.   
  • Files must have a <body></body> section.
  • The body section must have at least one node.
  • Each OPML node must contain either a text or title attribute.
  • If the node has a url, xmlUrl, or htmlUrl attribute, it must also contain a type attribute.
  • Valid values of the type attribute are: link, rss, include, feed, atom, rdf, opml.
  • A node with a type attribute can not have child nodes.

New version of OPML spec coming

Monday, July 16th, 2007

Dave is revising the OPML 2.0 spec. That’s great news. Maybe he’ll include some of our Grazr extensions in the core spec, so it won’t be necessary to use a namespace declaration.

Welcome to the Opmlosphere

Friday, March 9th, 2007

When we started building Grazr I kept getting asked what OPML was, because nobody had actually seen it. Now we have reached a new milestone. By placing the OPML file for the recent additions to Grazr.com into a Grazr widget you can now see and share other people’s OPML files as they add them to the site. If a feed reader shows you the blogosphere, then this widget can be said to display the opmlosphere.

 

Grazr news using Grazr on Grazr.com

Wednesday, March 7th, 2007

If being self-referential is a sign of postmodernism, then Grazr is truly a postmodern Web app. Marjolein Hoekstra has created an OPML file to display news about Grazr. She placed it in a Grazr widget, and posted it on Grazr.com. Maybe we should create a poster with a Grazr widget and the message “This is not a Grazr widget.” As a parental side note, one of my most memorable discussions with my college freshman son came this Christmas break when he spent an hour explaining how I didn’t really understand postmodernism. The best part is that he was absolutely right.

Placeblogger would be great…

Wednesday, January 3rd, 2007

If their terms of service didn’t block people from displaying their data. Placeblogger is a new site that lists feeds for blogs that are specific to locations. It does a great job of organizing these lists, and the best part is that all of the lists are available as OPML files. The only problem is that their terms of service says that nobody can display any of their data without getting written permission:

Placeblogger content is available for reuse for personal and noncommercial purposes. We encourage download and use of the OPML files for use by individuals in their personal RSS reader.

We do not grant permission for any institution or website to use or republish either the OPML files, directory listings, text, images, or other media from the directory or other portions of the site without our written permission. We worked very hard to compile our directory and wholesale theft of our work for use elsewhere will not be tolerated.

I could ask for permission, but even if they allowed me to put one of their reading lists in a Grazr nobody would be able copy that Grazr to their own site without also asking for permission. Notice that this limitation applies to any website. I hope Placeblogger rethinks its policy on use of their data. Asking for attribution and a link to the Placeblogger site when publishing their data would be fine, but a blanket restriction is a fatal flaw.

OPML Workstation reborn

Saturday, November 18th, 2006

Jim Moore has been awfully quiet for the last 2 months, and now I see why. Congratulations, Jim, Bela, and the rest of the gang. It looks great.

Anne Zelenka’s new gig

Thursday, November 16th, 2006

Anne is a former OPMLer who somehow lost her connection this spring during her move from Hawaii to Denver. She now has a new job as a columnist for Om Malik’s network. She’s always been a great writer, and her first post at Web Worker Daily is right on target. Maybe she’ll rediscover OPML again someday. It would be great to have her back.

(via Amy Bellinger)

OPath is coming along

Tuesday, November 14th, 2006

It looks like Tom Morris is making progress with his ideas for implementing an OPML anchor model. I still think a namespace extension will win in the long run, but as long as he is getting people to think about the issue that is a good thing. He seems to be having fun also.

OPML anchors

Saturday, November 11th, 2006

Tom Morris is working on a solution to linking to nodes within an OPML file that he calls Opath. Ultimately I think this problem calls for a namespace solution, but Tom is at least putting one answer into use.