Has anybody out there thought about advertising an OpenSearch service via ZeroConf [1]-style wide-area DNS Service Discovery [2] (DNS-SD)? A quick look at the DNS-SD SRV Service Types [3] doesn't seem to indicate as such, and a search for "opensearch and dns-sd" [4] or a search for "opensearch and zeroconf" [5] mostly shows hits back to this blog.

I see three reasons for considering this:

• Lets the discovery happen even when users are looking at one of your webapps or subdomains where you can't twiddle the HTML HEAD element (there are still plenty of these)
• Lets a remote service find out more about the institution running your network (modulo "but I'm not on that network now" problem, which plain ol' zeroconf itself could help)
• The more avenues for discovery the better

Er, those being "general reasons for anybody using OpenSearch to consider this". My own reasons extend these with more specifics about library-specific uses like metasearch and link resolvers, some details of which I've written up before [6].

One main drawback to all this is:

• Browsers and javascript-in-browsers don't do DNS

...or, well, Safari and Konq do, but not IE (not without a plugin, and "First Install This Thingy" doesn't scale) and not Mozilla/Firefox. But then again we could always proxy that with a web service, yadda, yadda. See also mozilla bug 14328 and discussion [7].

Defining an SRV type would be pretty straightforward - it probably only needs a key pointing to the path of the OpenSearch description document, since that's what that's for.