mark nottingham

Outage in the Web: Server Configuration

Wednesday, 17 March 2004

Web Feeds

In an otherwise excellent article, Jon Udell blames the lack of one-click subscribe in syndication formats on lack of vision;

How users will interact with the formats and APIs is left as an exercise for the implementer. But of course that’s where the rubber meets the road. So syndication still lacks a well-known mechanism for one-click subscribe.

In fact, there’s a clear path to one-click subscribe in syndication.

Here’s how: If every syndication format were served with a well-known media type (e.g., application/rss+xml), browsers could be configured to dispatch that format (which would need to contain a link back to the feed) to the user’s preferred aggregator or other client. With a little help, they could even be configured to dispatch to a Web aggregator.

It’s easy and simple, and it’s how the Web is designed. Unfortunately, there’s a catch; the phrase “were served.”

It turns out that most Web servers don’t know anything about application/rss+xml, so they don’t know how to serve it; if you put a .rss file on Apache today, you’ll probably get back text/html, which doesn’t do you any good for dispatching it.

It’s possible to configure Web servers to know about this, of course, but here’s the rub; most users either aren’t allowed to do so by their administrators, or don’t know how to, because the interface is so arcane.

The results of this problem are pretty far-reaching. For RSS, it means that people resort to hacks like the “feed” URI scheme, because it’s self-contained inside the URI, or a laundry list of “subscribe” links. In other situations, it means that people aren’t able to leverage the common facilities that the Web provides, like authentication, caching and redirection.

In fact, I could give an example of almost every facility that the Web provides being held back by this problem. Because of this, I’m saying that flexibility of server configuration a key outage for the Web. Next: a straw-man proposal for how to fix it.


Dumky said:

Actually a second fundamental problem with using the MIME type: you don’t want the aggregator to get the RSS file, but the URL for that file. It’s explained better at

Wednesday, March 17 2004 at 1:42 AM

Ken MacLeod said:

Another issue overlooked, and not mentioned exactly in Greg Reinacker’s linked entry, is that the feature request is “one click subscription” not “click to view this resource now and provide me the option to subscribe permanently” (a two-click operation to subscribe).

Of course, this is not to say servers shouldn’t be more easily configurable (they should) or that one click subscription using a one-off URI scheme is a good idea (it isn’t), only that if you’re going to use that case as an example you need to get the context right.

Wednesday, March 17 2004 at 2:16 AM

Joe Crawford said:

This reminds me of FutureSplash / Flash adoption a little. Perhaps some other old hands will remember this. There was a problem in Netscape (the dominant platform at the time) with being able to process [embed]ed content with the wrong mime-type served up – the solution was to explicity declare the type in the embed tag.

You can see someone complaining about exactly what you’re talking about – 8 years later – in this old usenet post:

Wednesday, March 17 2004 at 3:44 AM

Ken MacLeod said:

Mark, I don’t know. That’s not the impression I’ve been given by the pro-‘feed:’ folks. It’s never been “if the mime-types worked ubiquitously, that’d be great, no problem, just open up the aggregator and let it do its user-configured thing (display or auto-subscribe).” It’s always been more “action” oriented, “this kind of link means subscribe now” vs. an ‘http:’ link which means open up the link in the browser.

Wednesday, March 17 2004 at 6:42 AM

Carey Evans said:

When I actually set one up, I want to publish my RSS feed on HTTPS only, just to confound simplistic readers and so that feed: doesn’t work. (Although if I really wanted to be difficult, I’d use TLS Upgrade.)

Realistically, couldn’t a feed reader install a browser extension (BHO or XPI) to handle link elements and clicks on feeds? It’s still a hack around not setting MIME types, but it seems to me there’s plenty of room for innovation.

Wednesday, March 17 2004 at 10:20 AM

Alastair Rankine said:

I imagine that in 95% of cases, users on a given web server will configure their MIME type mappings in exactly the same way. In other words, there is unlikely to be any conflict between MIME type mappings from different users on the same server. Another way to solve this problem is to allow the global (ie per-server) MIME mappings to be more easily updatable, eg not require editing of httpd.conf.

On the general point of flexibility of Apache server configuration, I wholeheartedly agree. My ISP does not permit usage of mod_rewrite, because enabling this would also enable ErrorDocument, and this is an administration headache as a result of users who generate thousands of 404s per day. (This is AllowOverride FileInfo, if any Apache developers are reading this :)

Thursday, March 18 2004 at 1:09 AM

Danny said:

I’m in general agreement (current situation not good; feed: not good either), but just on the server config point, personal experience suggests that setting the mime type isn’t as widespread a barrier as often suggested. With all the various (mostly budget) web service providers I’ve used in the past few years it has been possible. If I remember correctly, the Linux-based ones all supported .htaccess, and I dropped a mail to admin of a Win32-based server and they did the honours for me (that one was for “image/svg+xml” - this isn’t just an RSS issue).

Anyhow, still looking forward to hearing the proposal…

Thursday, March 18 2004 at 1:54 AM

PJ said:

I’ve got no problem with syndication subscription… but I’m using the (very simple) firefox RSS Reader where my list of subscriptions is a subfolder of my bookmarks. This leverages all the extant tools for managing bookmarks, and gives me right-click-add-to-bookmarks functionality that makes it trival for me to subscribe to whatever I want.


Friday, March 19 2004 at 12:06 PM