what is the best way to convert a json formated key value pair to ruby hash with symbol as key?

Question

I am wondering what is the best way to convert a json formated key value pair to ruby hash with symbol as key : examole:

{ 'user': { 'name': 'foo', 'age': 40, 'location': { 'city' : 'bar', 'state': 'ca' } } }
==> 
{ :user=>{ :name => 'foo', :age =>'40', :location=>{ :city => 'bar', :state=>'ca' } } }

Is there a helper method can do this?

Answer 1

Of course, there is a json gem, but that handles only double quotes.

Answer 2

There isn't anything built in to do the trick, but it's not too hard to write the code to do it using the JSON gem. There is a symbolize_keys method built into Rails if you're using that, but that doesn't symbolize keys recursively like you need.

require 'json'

def json_to_sym_hash(json)
  json.gsub!('\'', '"')
  parsed = JSON.parse(json)
  symbolize_keys(parsed)
end

def symbolize_keys(hash)
  hash.inject({}){|new_hash, key_value|
    key, value = key_value
    value = symbolize_keys(value) if value.is_a?(Hash)
    new_hash[key.to_sym] = value
    new_hash
  }
end

As Leventix said, the JSON gem only handles double quoted strings (which is technically correct - JSON should be formatted with double quotes). This bit of code will clean that up before trying to parse it.