gistfile1.txt

// Handle specific permissions
app.service(resourcePath)
  .before({
    update: handleUpdatePermissions
  });

/**
 * Handle permissions when updating a project
 *
 * @param hook {Object}   -
 * @param next {Function} -
 */
function handleUpdatePermissions (hook, next) {
  var user = hook.params.user;
  var projectId = hook.id;

  return next(new Error('Just for test'));
  /* propagate and crash the server with an error 500 response
  for the client. How to handle that knowing I don't have access
  to the generated rest route for the update (PUT) */ 
  
}

Well, we sort of support this with feathers-associations but after starting down that road we realized that you don't even actually need routes like that. You could just call /api/users/2. No need to complicate it by adding more params to your route.

Think about it, when you are calling /api/groups/123/users/2 you already have the user ID. This has come up quite a few times so we are going to be addressing it much more clearly in the documentation in the next release.