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

You can create a filter that runs before any controller call and apply the following instructions to it:

# transform camel case string into snake case
snake_string  = Proc.new {|s| s.gsub(/([a-z])([A-Z])/) {|t| "#{$1}_#{$2.downcase}"}} 

# transform all hash keys into snake case
snake_hash    = Proc.new do |hash| 
  hash.inject({}) do |memo, item|
    key, value = item

    key = case key
          when String
            snake_string.call(key)
          when Symbol
            snake_string.call(key.to_s).to_sym
          else 
            key
          end    

    memo[key] = value.instance_of?(Hash) ? snake_hash.call(value) : value
    memo
  end
end

params = snake_hash.call(params)

You must have to consider the above procedure will impose a small overhead on every Rails call.

I am not convinced this is necessary, if it is just to fit in a convention.