What is the best way to convert all controller params from camelCase to snake_case in Rails?

Question

As you already know, JSON naming convention advocates the use of camelSpace and the Rails advocates the use of snake_case for parameter names.

What is the best way t

Answer 1

tlewin's answer didn't work for me in Rails 3. it seems the params' = operator renders future operations on it void. very strange. anyways the following works for me, as it only uses the []= and delete operators:

before_filter :underscore_param_keys
def underscore_param_keys
  snake_hash = ->(hash) {
    # copying the hash for iteration so we are not altering and iterating over the same object
    hash.to_a.each do |key, value|
      hash.delete key
      hash[key.to_s.underscore] = value
      snake_hash.call(value) if value.is_a? Hash
      value.each { |item| snake_hash.call(item) if item.is_a? Hash } if value.is_a? Array
    end
  }
  snake_hash.call(params)
end