Helper apps, itms protocol, and us Rev folk

[Richard Gaskin]

Apple has invented an Internet protocol named "itms" ("iTunes Music 
Store") so folks can put links on their web pages and clicking on those 
links automatically launches iTunes to the specified URL.

While the links themselves are wrapped in JavaScript to attempt verify 
that they'll work first, a typical link resolves to something that looks 
like this:

<itms://ax.itunes.apple.com/WebObjects/MZStore.woa/wa/viewPodcast?id=80616768&s=143441&ign-mscache=1>

It appears that the iTunes installer registers the itms protocol when 
it's installed (prefab on OS X and using the Registry on Windows).

It would be helpful to have a similar behavior for our own apps, the 
ability to have links on our site to stack files which launch our own 
standalone to run them.

I've noticed that when using simple http links the user is asked (in FF 
and IE, anyway) whether they want to download the file or open it with a 
specific app, and they can specify your standalone and in some versions 
even check a box to always take that action when handling files of that 
type.

But that's a lot to ask of users.

I understand the security implications of having such setup happen 
automatically, but it sure would be convenient.

How does iTunes register its itms protocol, and can we do the same for 
our own apps?  Or is there a way to set up a Helper app to always handle 
files of a specific type?

I don't think it's too much to ask if such installation requires admin 
permissions, but it would be very handy to have some way to do this.

Any clues?

--
  Richard Gaskin
  Fourth World
  Revolution training and consulting: http://www.fourthworld.com
  Webzine for Rev developers: http://www.revjournal.com