class Hash # Returns a JSON string representing the hash. # # Without any +options+, the returned JSON string will include all # the hash keys. For example: # # { :name => "Konata Izumi", 'age' => 16, 1 => 2 }.to_json # # => {"name": "Konata Izumi", 1: 2, "age": 16} # # The keys in the JSON string are unordered due to the nature of hashes. # # The :only and :except options can be used to limit the # attributes included, and will accept 1 or more hash keys to include/exclude. # # { :name => "Konata Izumi", 'age' => 16, 1 => 2 }.to_json(:only => [:name, 'age']) # # => {"name": "Konata Izumi", "age": 16} # # { :name => "Konata Izumi", 'age' => 16, 1 => 2 }.to_json(:except => 1) # # => {"name": "Konata Izumi", "age": 16} # # The +options+ also filter down to any hash values. This is particularly # useful for converting hashes containing ActiveRecord objects or any object # that responds to options in their to_json method. For example: # # users = User.find(:all) # { :users => users, :count => users.size }.to_json(:include => :posts) # # would pass the :include => :posts option to users, # allowing the posts association in the User model to be converted to JSON # as well. def to_json(options = {}) #:nodoc: hash_keys = self.keys if options[:except] hash_keys = hash_keys - Array(options[:except]) elsif options[:only] hash_keys = hash_keys & Array(options[:only]) end returning result = '{' do result << hash_keys.map do |key| "#{ActiveSupport::JSON.encode(key)}: #{ActiveSupport::JSON.encode(self[key], options)}" end * ', ' result << '}' end end end