ActionController Parameters require a hash, not primitive

Question

I'm fairly new to Ruby but I have read dozens of articles and ended up with no solution for this issue:

I'm trying to make my API controller bulletproof. In order to validate requests, I'm using ActionController::Parameters .

For example, in my Users API controller:

params.require(:user).permit(:email)

If someone calls this with {"user": "abc"} , it results in an error, and HTTP 500, when it's clearly the user's fault for not passing in user as a hash, and should result in a HTTP 400:

NoMethodError in API::UsersController#update
undefined method `permit' for "abc":String Did you mean? print

How do I ensure the user of my API passes in a hash?

Answer 1

There is this method that you can use: dig (ruby 2.3):

Retrieves the value object corresponding to the each key objects repeatedly.

http://ruby-doc.org/core-2.3.0_preview1/Hash.html#method-i-dig

So you could say params.dig(:user, :email)

You could also say params[:user].has_key?(:email) but the first one is better

Also on related note not sure if you should handle with 400 - I think that 422 may be better since it is 422 - Unprocessable Entity

but not important...