stargeek
on OPMLon OPMLon OPML 01/11/2004 09:23 PM On my previous entry about Postel's Law, Danny Ayers made a comment, and to a part of it I said I'd reply in a separate entry. To make the question clear, I'll restate it here in a different way to involve the technology only. Essentially, Danny was asking "If you have used OPML, would you agree that OPML does not follow this route you are advocating of adding as many constraints as possible to a spec, to make interoperability easier?" (Danny, if I misunderstood the question please let me know, but I'm pretty sure that was the essence of your comment, personal matters aside). My answer to that question would have to be no, I do not agree. Let me explain. I have implemented both readers and writers of OPML when used for RSS subscription lists for an end-user product (ie, clevercactus). And there is one main point that I've found frustrating, namely that the attributes used on the "outline" element vary between tools. I have previous ly noted, in another context the elements that would "complete the spec" by properly specifying these attributes. However, I've come to the conclusion that this is not a problem with the spec itself, but rather a problem of what are we using it for. As far as I can read in the spec, it was designed to be a very simple and flexible storage mechanism. The first sentence in the spec says "This document describes a format for storing outlines in XML 1.0" (my emphasis). It doesn't say "This is a format for interchange of outlines" or anything like that. That is, creating an interoperable format for RSS subscription lists was not part of the original "charter" of OPML. Which is why I can't agree with Danny's statement, because the interoperability problems we all know about pop up when using OPML outside of its original intended domain. As such, that is, as a format for local storage of outlines, the OPML spec might have done a good thing by keeping things very open. Note that the spec explicitly says, in its goals: "Outlines can be used for specifications, legal briefs, product plans, presentations, screenplays, directories, diaries, discussion groups, chat systems and stories." -- that's a big set of apps, and I'd be hard pressed to define a consistent set of common attributes for all of them. To be honest, if it was me designing it maybe I would have chosen a different path (like for example target less applications), but that's not really the point. Design is at its core subjective. So. Given that OPML was not originally designed as an interoperable way to store feed subscription lists, the current situation is logical, almost predictable. It seems to me (given what I've seen--I might be wrong of course) that this is a use of OPML that grew in ad-hoc fashion and as such created some incompatibility problems. But is this a problem with OPML itself? I don't think so. Usage grew beyond its original intended target, and things got a bit messy. Okay, that's my answer to Danny's question, but I just want to be clear on what I think about OPML given the current situation, as what I said above might seem a bit too ... err... "theoretical". That is, we still have the interoperability problems for feed subscription lists. However, now that it's clear that it has become accepted for that use, I noticed that Dave recently put up a short RFC that clearly states "Using OPML to exchange subscription lists". My comments from October last year would, then, apply in this new context, and the new RFC already covers part of them (the most important in my mind, which is the issue of standard attributes). This new spec of "Interchangeable OPML Subscription Lists" plus the OPML spec itself (which doesn't necessarily need to change, since it is still relevant in its original intended domain) make a simple combined spec that is useful and already deployed (granted, some aggregators might be generating different attribute names that those on the RFC, but that's a tiny change, and none of the other items under discussion that I'm aware of are in any way "deal-breakers"). Hence, OPML applied to the domain of feed subscription lists in particular is a good solution, simple and to the point. And to me that's what matters: if something does what I need, it's simple, and it works, I'm all for it. This is a GrokNews Entry: (what is grok?)on OPMLGrok Headline matches for on OPMLXML-OPML-0.1.6XML-OPML-0.1.6 02/19/2004 06:06 PM XML-OPML-0.1.4XML-OPML-0.1.4 02/17/2004 10:32 AM XML-OPML-SimpleGen-0.01XML-OPML-SimpleGen-0.01 03/23/2005 09:32 AM OPML RevisitedOPML Revisited 03/14/2005 05:44 PM OPML is a simple, widely used, yet often misunderstood, XML format created by Dave Winer. IMHO, misunderstandings stem from overexposure to traditional ways of using XML. I must admit, I also laughed at OPML when I first looked at it years ago. But when I cocked my head (a technique anyone can learn from their dogs), it began to make a lot of sense. This is what I saw: Infoset:
Syntax:
Once you get this picture in your mind, you start to appreciate OPML more. Throw in display and interaction semantics builted into the format along with distributed object linking and embedding Dave often raves about and you got quite a beast of a language. As to the question of who defines the properties, the answer is everybody does. OPML is a kind of Emergent Markup Language in that common properties are expected to emerge through industry practices rather than standardization through committees. There are some shortcomings with OPML though which I would like to see addressed. OPML Wiki OPML needs a wiki for OPML developers to interact with each other and to document how each of them are using OPML so that standard or type-specific properties may emerge. Structured Properties One weakness of XML is that, while elements may be structured, attributes may not. Since properties are encoded as XML attributes in OPML, (semi) structured properties (i.e. HTML fragments) have to be encoded at the cost of readability. I think the need for a wiki is far more serious than the need for structured property support. ScriptingNews2 and OPML tooScriptingNews2 and OPML too 10/28/2003 11:06 PM I've added ScriptingNews2 and OPML versions of my feeds. If anybody has any interesting applications of these feeds, please let me know. "Share your OPML""Share your OPML" 01/04/2004 03:53 AM XML-OPML-SimpleGen-0.02XML-OPML-SimpleGen-0.02 03/23/2005 03:44 PM OPML, Book AuthorsOPML, Book Authors 10/28/2003 11:07 PM Just got back from a meeting with a bunch of book authors, here for the publishers' summit. They're all under NDA, of course, but sometimes I am still surprised at how much some of these people know. Robert Scoble is organizing a bloggers /authors dinner at Crossroads tonight, which I'll also be attending. ~ In other news, I finally admitted defeat in my effort to manually track all of the MSFT bloggers. You will notice that my link on the left now points to an OPML file instead. There are well over a hundred, and it was getting too difficult to keep up with it. Now I can just maintain the OPML file, visitors to the site can import it to their news aggregators automatically, and it has an attached XSLT so that it renders nicely in the browser if you view it from my site. I started with an OPML file that Benjamin Voigt kindly constructed for me, then merged with the OPML file from blogs.gotdotnet.com. Strangely enough, I was still missing quite a few names after doing this (for example, Mark Fussell and Arpan Desai did not show up on the gotdotnet OPML, even though their blogs are hosted by gotdotnet; and Dare Obasanjo was not on Benjamin's list). I suspect that there are at least 20 more MSFT blogs that I am missing, but this should be the most complete list available. Note that the OPML file is rendered using the stylesheet at /blog/blogOpml.xslt, which is a ridiculously simple XSLT you can modify any way you like. I would like to modify it to sort the blogs by most recent update, but really would rather not do that using XSLT. "Share your OPML: Rankings""Share your OPML: Rankings" 01/04/2004 03:53 AM logos OPML directorylogos OPML directory 12/30/2003 12:06 AM Oskar van Rijswijk has a great collection of OPML files on his site. Just browse his OPML directory in FeedDemon, then click any of the OPML links to create a new FeedDemon channel group. Top 100 feeds, share your OPML!Top 100 feeds, share your OPML! 01/03/2004 07:12 AM I submitted my OPML feed tonight and was number 135 I submitted 399 feeds from my basic read list. This... Share Your OPML Top 100 FeedsShare Your OPML Top 100 Feeds 01/07/2004 02:58 PM Share Your OPML: Top 100 Feeds, of course, has a feed for the list.... share your opml subscriptions listshare your opml subscriptions list 01/03/2004 05:56 AM ranking service feeds.scripting.com MyYahoo Adding RSS, OPML SupportMyYahoo Adding RSS, OPML Support 01/23/2004 01:27 AM Scott Katz, from Yahoo's MyYahoo personalization area, points me to a beta version of an RSS module for MyYahoo pages. He says: "While still an early release, we'd appreciate it if you (and your readers) would help us test it and provide feedback. It's not widely available today -- you need to visit a hidden URL to add it to your My Yahoo page. Once you've got the module, you can search and add feeds or import OPML files." Export Your NetNewsWire OPML ListExport Your NetNewsWire OPML List 10/29/2003 01:14 AM NetNewsWire uses an OPML file for it’s backup/export means. This file has just enough information to do useful things with it. Go get PHP-OPML and upload it to a directory on your webhost. Export your NNW subscriptions and then upload... OneNote OPML Import ToolOneNote OPML Import Tool 05/03/2004 03:20 PM Well someone has went and made a OneNote OPML import tool but how come they don't have an export tool.... Better Living Through Software - OPML
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