classID: Components.ID("{b7ad6144-d344-4687-b2d0-b6b9dce1f07f}"),
 QueryInterface: XPCOMUtils.generateQI([Ci.nsIProtocolHandler]),

 scheme: "app",
 defaultPort: -1,
 // Don't allow loading from other protocols, and only from app:// if webapps is granted
 protocolFlags: Ci.nsIProtocolHandler.URI_NOAUTH |
                Ci.nsIProtocolHandler.URI_DANGEROUS_TO_LOAD |
                Ci.nsIProtocolHandler.URI_CROSS_ORIGIN_NEEDS_WEBAPPS_PERM,

 getAppInfo: function app_phGetAppInfo(aId) {

   if (!this._appInfo[aId]) {
     this._appInfo[aId] = appsService.getAppInfo(aId);
   }
   return this._appInfo[aId];
 }, 

We have the following website: http://windowsapps.com that uses the app:// protocol to launch apps with our custom software, appWave. With the latest versions of FireFox when clicking an app:// link in our site with our app installed, nothing happens. I've reviewed the firefox source code and found OUT that the app protocol is blocked by default now AppProtocolHandler.prototype = { classID: Components.ID("{b7ad6144-d344-4687-b2d0-b6b9dce1f07f}"), QueryInterface: XPCOMUtils.generateQI([Ci.nsIProtocolHandler]), scheme: "app", defaultPort: -1, // Don't allow loading from other protocols, and only from app:// if webapps is granted protocolFlags: Ci.nsIProtocolHandler.URI_NOAUTH | Ci.nsIProtocolHandler.URI_DANGEROUS_TO_LOAD | Ci.nsIProtocolHandler.URI_CROSS_ORIGIN_NEEDS_WEBAPPS_PERM, getAppInfo: function app_phGetAppInfo(aId) { if (!this._appInfo[aId]) { this._appInfo[aId] = appsService.getAppInfo(aId); } return this._appInfo[aId]; }, Is there any way that my app can programatically onblock the app protocol?