RE: NSD spec implementation feedback

Frederick, all,

Use cases are always good to have.
As it is often mentioned that the NSD API without XHR is useless, here are some use-cases that do not require XHR use.

Regards,
                Youenn

Case 1: Media player that controls XBMC using JSONP
XBMC supports interaction with plain HTTP GET + JSON.
Discovery of XBMC address is needed (could be indirectly done by discovery of XBMC UPnP services).

Case 2: Get temperature from remote arduino devices
Using Arduino REST API, a web application can get the temperature from the device using GET requests.

Case 3: Printer tutorial application
The application customizes what is displayed (manual, hints...) to the user based on printers available on the local network.
The application may also help an operator setting up printers:

-          the app provides tutorial information on how to do the set-up

-          the operator interacts with the printer in a separate admin interface (tab or iframe) launched from the web application

Case 4: Video-conference hook-up application
A user enters a meeting room, launches a web application that will find information on on-going video-conferences.
Information is broadcasted through MDNS and can be WebRTC session information (SDP offers...) or simply a URL to a local/remote web site.

Case 5: browser extension
All of the above cases may be implemented as browser extensions.
Implementing the NSD API for browser extensions would be a first step towards wider adoption.
It may also help gather knowledge of whether or not to filter discovery protocol data (and how).

A last use-case is hosted web apps for which XHR can be used without the need for CORS/whitelist
Case 6: A media player hosted app
The hosted app is already authorized at installation time to do any cross-origin HTTP, typically to retrieve media from various web sites.
NSD would just be used to discover local services, in particular UPnP media storage devices.
No need for CORS/whitelist here as the hosted app is trusted.