Dealing with List Feeds


Recently, I received an interesting customer question I thought I would share.

A web developer presented me with the following scenario: his web application lets users create and manage a list of items, and this list is exposed as a feed so users can be updated when it changes. However, after the user deletes an item using the web application, that item is still present in the feed view of the RSS aggregator. Since the feed is supposed to correctly reflect the state of the user’s item list, this was a problem.

Unfortunately, the desired behavior doesn’t quite work with established feed usage. A majority of feeds expose only a small number of most recent items and older items periodically get aged out. But you wouldn’t want to miss posts from your favorite blog or news feed just because you went on vacation and those posts are no longer in a feed! This is why the Windows RSS Platform stores all the items until the user-controllable feed item storage limit is reached (200 items by default).

Fortunately, I had good news for the customer – there is a very simple solution to his problem!
IE7 and the Windows RSS Platform fully support feeds that contain a complete ordered list of items. All you need to do to make your feed a list is add one simple extension under the <channel> node (or for Atom feeds, under the <feed> node):

<channel>
  <cf:treatAs xmlns:cf=”http://www.microsoft.com/schemas/rss/core/2005″>list</cf:treatAs>

</channel>

The “treatAs” extension is part of the Simple List Extensions (SLE). These are the feed extensions we designed with the exact purpose of exposing ordered lists of items in a feed, and made available to everyone under the Creative Commons license. SLE follow the feed extensions rules so they work in combination with other RSS extensions and the resulting feed can be read with any feed reader. You can find the full explanation with samples and pointers to live list feeds in one of our earlier posts on the RSS team blog here, or get a hands-on experience with the recently posted RSS lab at the MIX University.

Needless to say, the customer was pretty happy with how easy this was.

If you haven’t looked at the SLE already, this might be a great time to do so. They might just be the perfect answer for your scenario.

Miladin Pavlicic
Senior Developer

Comments (20)

  1. Anonymous says:

    I’m curious – do you know if Windows Live Writer supports this?

  2. Anonymous says:

    Hm, I can’t help but think this is open for misuse. Interesting feature, though.

    Is there a registry value I can create to turn off this behavior?

    I wouldn’t like it if any of my feeds used this, and I can’t really imagine a scenario where I would want this.

  3. Anonymous says:

    Here’s an idea, instead of showing us some new proprietary mumbo jumbo, why don’t you 500 idiots working on this ONE program implement rgba() from the CSS 3 spec.  Jesus, all the money in the world and YEARS between new versions and you can’t implement the most rudimentary new properties.  What a bunch of lazy bums you all are.

  4. Anonymous says:

    Nice stuff! Hope that more readers will use this!

    And John: It’s better to see a bunch of lazy bums then one frustrated NERD

  5. Anonymous says:

    I am downloading 1.8 Gb file in Internet Explorer. It finishes and starts

    copying from the temp directory to the Desktop, where I asked it to be saved.

    Except, at this exact moment, I am writing an email, and I press the space

    bar… the copy dialog has popped up in front of my email and taken focus

    without my consent, and now my pressing of the space bar has cancelled my

    download!

  6. Anonymous says:

    @Luc: That was fixed in IE7.  You should upgrade.

  7. Anonymous says:

    Hi guys,

    Sorry to leave an off-topic comment but with the Connect site being closed I have no other way of reporting this bug.

    Basically, when we installed IE7 on our Windows Server 2003 Terminal Servers it messed up our stationary in Outlook.  We had the stationary set up so that it placed our logo (jpeg format) at the bottom of each e-mail underneath the signature but once IE7 was installed the logo now appears at the begining of each e-mail and the body text starts underneath this.  

    It looks terrible and some of our workers are not intelligent enough to drag the logo to the bottom of the e-mail so they have been sending e-mails with the logo at the top and the body following it.  I am getting lots of grief about this and I just wondered if its something you guys know about?

    Thanks.

  8. Anonymous says:

    "Here’s an idea, instead of showing us some new proprietary mumbo jumbo, why don’t you 500 idiots working on this ONE program implement rgba() from the CSS 3 spec."

    Isn’t CSS3 a draft currently? You know, as in not an actual recommendation?

    If they would implement rgba() right now, it would also be "proprietary mumbo jumbo".

    Secondly, there is more to the internet than CSS.

  9. Anonymous says:

    Rob: yes, the popular blog posting tools are compatible with list extensions.  When you delete a post with a client like Windows Live Writer, it disappears from the list.  The server simply needs to add that tag to the RSS feed generation routine.

    TMaster: none of your feeds use the list behavior if you do not add the treatas:list element.  So if you haven’t specified that the feed is a list, it won’t be treated as a list.  If you subscribe to a feed that the author has designated as a list, it will be treated as a list.  An example is the Yahoo! "Top 10" videos list, or an Amazon WishList.  If you want to keep a record of items that someone has *removed* from their Amazon WishList, you will need to capture a copy of the feed regularly and save copies.

  10. hswear3 says:

    Hi,

    I know this is off-topic; but the IE bug reporting tool on connect is offline.

    I really like IE7 but there are two aggrivating issues that I wish you would fix:

    1. When IE crashes or hangs and has to be shut down, all of the open tabs are lost. There really should be an option to reopen them when IE is restarted.

    2. The timeout when saving web pages is way too long (or sometimes infinite). I frequently have this happen. The dialog box that is displayed is modal so I can’t switch to another tab. Also the cancel button is inoperative. Sometimes this completes after 30 minutes or so; sometimes I loose all of my open tabs because I have to use Task Manager to close IE.

    Thanks for reading this!

    Herbert N Swearengen III (hswear3 AT swbell DOT net)

  11. Anonymous says:

    The saving a web page feature has been broken for a long time. It will always just hang on things like news sites that contain lots of images and links and things, and like you say the dialog is mondal and cancelling will often not work.

  12. Anonymous says:

    when i installed ie7 everytime i open the program it goes to a page that says in the browser addy bar "runonce page" instead of going to the home page that i have it set to? any idea’s?

    thanx much

  13. Anonymous says:

    Bug Submission:

    Bug Submission Date: Daily since November 2006

    Bug Description:

    IE Connect Feedback site broken since November 2006.

    Bug Details:

    As mentioned only a million times, this is a required tool for users/developers of a web browser (esp. one with the majority of the market share, and the majority of the bugs)

    Related Bug(s):

    Yes, several, including lack of development and roadmap transparency.

    Lack of feedback to developers.

    Lack of information about bug fix status/dates

    Lack of confidence that MS really does care about developers.

  14. Anonymous says:

    The saving a web page feature has been broken for a long time. It will always just hang on things like news sites that contain lots of images and links and things

  15. Anonymous says:

    The saving a web page feature has been broken for a long time. It will always just hang on things like news sites that contain lots of images and links and things

  16. Anonymous says:

    IE 7 cannot display YouTube RSS feeds:

    http://www.youtube.com/rssls

    Obviously – its their bug but it is interesting to hear your opinion on this.

  17. Miladin says:

    Anatoly: I am looking at the YouTube feeds and IE7 displays them perfectly.

    There was a problem with linking, in particular the way YouTube used the link tag (as you pointed out on your blog, they used something like this <link>(‘http://youtube.com/?v=cVcH_o1imWA‘,)</link>), but that seems to have been fixed and everything works just fine now.

  18. Anonymous says:

    @steve: If you’re hitting the Save button on the runonce page and it still doesn’t work, see the tip at the bottom of http://www.enhanceie.com/ie/troubleshoot.asp

  19. Anonymous says:

    IE 7 is so much more user friendly than previous versions, if only because of the tabs. For developers it is a really good program, although it still has its quirks. But what I found it is really lacking if compared to firefox is the live-bookmarks with rss. In firefox in a bookmark folder all headlines of a particular website are shown. In IE and other browsers I have to open a tab or a new window and scroll through the list of items.

  20. Anonymous says:

    @Jerry

    If you like Live Bookmarks, you should try the Feed Folders add-on:

    http://www.enhanceie.com/ie/FeedFolder.asp