NestedAccessors

This class lets you quickly add serialized, nested hash accessors in ActiveRecord model objects, using regular text database columns.

class Person < ActiveRecord::Base
  include NestedAccessors

  nested_accessor :info, [ :name, :phone ]
end

This would synthesize accessors to the name and phone properties contained in the info hash.

foo = Foo.new
foo.name = "bar"
foo.phone = "+46-123-45678"
foo.info #=> { "name" => "bar", "phone" => "+46-123-45678" }

If we want just a single name accessor we can remove the array:

nested_accessor :info, :name

Installation

• Add the gem to your Gemfile:

    source :rubygems
    gem 'nested_accessors', :git => '[email protected]:avocade/nested_accessors.git'
  

• Run bundle install

Dependencies

Requires ActiveRecord for the serialize class method. (To be reconsidered.)

Nested hash

You can nest accessors one level deep. To add more than one nested hash accessor to address we specify street and city inside an array.

nested_accessor :info, address: [ :street, :city ]

This gives:

object.address_street  # these two are nested inside the "address" hash
object.address_city

To just specify just one accessor, eg address[street], we can simplify:

nested_accessor :info, address: street

Note: The hash keys are always strings, never symbols. This is for consistency of input/output.

Testing

Run the minitest specs using:

rake

TODO

• Add assertion checking for args

• Switch to using supermodel gem for testing active_model serialize dependency properly instead of stubbing it out

• Allow setting default value for each accessor, eg last_name: "Doe"

• Create object wrappers for each nested hash, so can get accessors like person.address.street for person[address][street]

• Add two-level nesting, eg foo[bar][name][surname]

• Array with nested Hash objects inside, eg foo[bar][1][name]

• Perhaps switch convention to always use symbolic keys instead of stringified keys, so can use new ruby 1.9 hash syntax:

    foo.info = { name: "Anders" }
    foo.info[:name]
  

• Add typed arguments for each accessor (defaults to String)

    nested_accessor :info, phone: Integer
  

Author

Oskar Boethius Lissheim is a Product Designer and iOS & Ruby on Rails developer. He currently lives in Gothenburg, Sweden.

You can reach him on App.net at @avocade, or Twitter.

License

This code is offered under the MIT License.

Copyright © 2012 Oskar Boethius Lissheim.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.