Dealing with List Feeds

Articolo
02/12/2007

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):

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 postson 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
SeniorDeveloper

Comments

Anonymous
February 12, 2007
I'm curious - do you know if Windows Live Writer supports this?
Anonymous
February 12, 2007
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.
Anonymous
February 12, 2007
The comment has been removed
Anonymous
February 12, 2007
The comment has been removed
Anonymous
February 12, 2007
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!
Anonymous
February 12, 2007
@Luc: That was fixed in IE7. You should upgrade.
Anonymous
February 12, 2007
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.
Anonymous
February 13, 2007
"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.
Anonymous
February 13, 2007
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.
Anonymous
February 13, 2007
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Anonymous
February 13, 2007
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.
Anonymous
February 13, 2007
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
Anonymous
February 13, 2007
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.
Anonymous
February 13, 2007
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
Anonymous
February 13, 2007
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
Anonymous
February 13, 2007
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.
Anonymous
February 13, 2007
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.
Anonymous
February 13, 2007
@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
Anonymous
February 25, 2007
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.
Anonymous
February 25, 2007
The comment has been removed

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Dealing with List Feeds

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