long running actions

Hi Johannes,

In respect to the distinction between short and long running actions, I thought it would be worth some further discussion.

Even short lived actions should be considered as asynchronous due to the possible delays incurred by invoking them across the Internet, and the possibility of waiting for a sleeping device to awake.

For really long lived actions, it becomes interesting to consider a means to provide a progress indicator and a means for cancelling the action. One idea is for the method used to invoke the action to synchronously return an identifier that can be used to cancel the action, and potentially to drive a progress indicator.

If the method used to invoke the action returns a promise, I guess the identifier could be a property on the promise, but am unsure of the details. We should look into that.

Cheers,
—
   Dave Raggett <dsr@w3.org <mailto:dsr@w3.org>>