Persistent Object

Transparently persist objects to disk as YAML or PStore files.

$ gem install pobject

Or with bundler:

gem 'pobject'

Your object should inherit from PObject.

require 'pobject'

class Settings < PObject
end

Now, any time you access a property, it is saved to a file. By default, we will save a YAML file with the same name as the class.

class Settings < PObject
end

config = Settings.new
config.port = 3000
# Will create a 'settings.yml' file and store the port value

You can access any property by either dot notation or hash notation.

config.port
# => 3000

config[:port]
# => 3000

To change the location of the file, simply override the to_store method.

class Settings < PObject
  def to_store
    "config/local.yml"
  end
end

config = Settings.new
config.port = 3000
# Will create a 'config/local.yml'

Whenever you use the .yml (or .yaml) extension, we will store a YAML file. If you wish to store a PStore object instead, use any other extension.

class Settings < PObject
  def to_store
    "config/local.pstore"
  end
end

To store several objects in one store file, your to_store method should return an array with two elements: The first, is the path to the file and the second is any unique key identifying the instance.

class Hero < PObject
  def initialize(id)
    @id = id
  end

  def to_store
    ["heroes.yml", @id]
  end
end

hammer = Hero.new :hammer
raynor = Hero.new :raynor

hammer.name = 'Sgt. Hammer'
raynor.name = 'Raynor'

puts File.read 'heroes.yml'
# => 
# ---
# :hammer:
#   :name: Sgt. Hammer
# :raynor:
#   :name: Raynor

By default, PObject will raise an error when accessing a property that does not exist. To change this behavior, call allow_missing at the beginning of your class.

class Book < PObject
  allow_missing
end

book = Book.new
book.author
# => nil