Setting user's email on Facebook signup with Parse.com - facebook-graph-api

Question

I'm using Parse.com and trying to set up user sign up with Facebook.
Upon authentication with Facebook for the first time a beforeSave is called on _User to fetch additional user details:
function UserBeforeSave(request, response){
var user = request.object,
auth = user.get('authData');
// check if user is newly registered
if (!user.existed()) {
// Check if a user signs up with facebook
if (Parse.FacebookUtils.isLinked(request.object)) {
// Query Graph API for user details
Parse.Cloud.httpRequest({
url:'https://graph.facebook.com/v2.2/me?access_token=' + auth.facebook.access_token,
success:function(httpResponse){
// Map facebook data to user object
if (httpResponse.data.first_name) request.object.set('first_name', httpResponse.data.first_name);
if (httpResponse.data.last_name) request.object.set('last_name', httpResponse.data.last_name);
if (httpResponse.data.email) request.object.set('email', httpResponse.data.email);
response.success();
},
error:function(httpResponse){
console.error(httpResponse);
response.error();
}
});
} else {
response.success();
}
} else {
response.success();
}
}
Problem is that that email line is actually breaking the operation with error:
Can't modify email in the before save trigger
I tried moving this code to the afterSave but the authdata is not available there making it difficult to call the FB API. The email is therefore left blank at the moment.
I'm assuming this is a very common use case of integrating Parse with the Facebook API, am I missing something in the integration process that automatically fetches the email?

Answer 1

I just do the graph query client-side and set email there. This works fine.
Is there a reason you want to do it in the before/afterSave on the User?