coerce_empty_strings.rb

# Recursively coerce empty string values in hash -particularly
# useful for HTTP POSTed forms.
# Values are coerced based on the rules mapping of params_hash keys to coerced values.
# See http://dev.rubyonrails.org/ticket/5694 for background
def self.coerce_empty_strings(params_hash, rules = {})
  return unless params_hash
  params_hash.each_pair do |k,v|
    # AR::Base.extract_callstack_for_multiparameter_attributes can't handle nil values
    unless k.include?('(')
      params_hash[k] = rules[k.to_sym] if v.kind_of?(String) && v.empty?
      params_hash[k] = coerce_empty_strings(v) if v.kind_of?(Hash)
    end
  end
end