Calling Parse.Cloud.beforeSave() From custom web hooks - parse-platform

Question

I started off cloning the cloud code example blog app. And in the controllers I have the basic REST crud operations. I tried adding the code here to my controller, as well as just directly in main.js:
Parse.Cloud.beforeSave(Parse.User, function(req, res)
{
for (var dirtyKey in req.object.dirtyKeys()) {
if (dirtyKey === "username" || dirtyKey === "email") {
res.error("User is not allowed to modify " + dirtyKey);
return;
}
}
res.success();
})
In my terminal, I am running parse develop [app] to update files as I change. And when I add the above code it does register a trigger.
Deploying recent changes...
Your changes are now live.
I2014-07-15T03:30:18.108Z]Deployed v63 with triggers:
_User:
before_save
Yet I am still able to, from the rest api using postman, able to update the username and email fields.
I suppose, that the real question should be, is that if I am building my app like this; do I still use these beforeSave() triggers like described? Or is it better to simply make those checks in the method (in this case, the User.update method i created) and validate everything there? Because I cant seem to get the triggers to actually run.

Answer 1

The issue is a common mistake with how for..in works in JavaScript with an array, in your code above dirtyKey will be populated with the index, what you want instead is:
for (var i in req.object.dirtyKeys()) {
var dirtyKey = req.object.dirtyKeys()[i];
if (dirtyKey === "username" || dirtyKey === "email") {
res.error("User is not allowed to modify " + dirtyKey);
return;
}
}