[SOLVED] Mongoid: How to validate value of specific key on Hash field?

Mongoid: How to validate value of specific key on Hash field?

In Mongoid, I can set an index on the attribute of a field whose type is Hash as follows:

index({ "details.fullName" => 1 }, { name: "full_name_index" })

What I'd like to do is create validations for such entities using something like the following:

validates "details.fullName", presence: true

Unfortunately, this produces the following error:

NoMethodError: undefined method `details.fullName' for Thing

Did I make a syntax mistake, or is this feature simply not supported in Mongoid 3?

Solution

Since Hash data type is unstructured hash value (i.e. it doesn't have any reference to the keys inside the hash, you can literally stick any hash string in there), you will have to write a custom validation method:

validate :details_has_full_name

def details_has_full_name
    errors.add(:details, "Some Error Message") if details["fullName"].nil?
end