This acts_as extension implements a system label and a friendly label on a class and centralizes the logic for performing validations and accessing items by system label.
The extension is particularly useful for tabled, enumerated lists.
The system label is declared as a read-only attribute, allowing models and controllers to code to the value safely, secure in the knowledge that the value will never change.
The friendly value can be changed to any value required by the end-user without affecting the model/controller code in any way.
If you just want validations and system label accessors, simply add acts_as_label to the model.
class Role < ActiveRecord::Base acts_as_label end
The plugin accepts three optional parameters.
system_label_column-
specifies the name of the column to use for the system label (default: system_label)
label_column-
specifies the name of the column to use for the label (default: label)
default-
specifies the system label value to use as the default record
class Role < ActiveRecord::Base acts_as_label :system_label_column => :key, :label_column => :name, :default => :guest end
If you use the plugin within a single table inheritance (STI) design, the easiest way to specify a default record is by implementing a class method on the subclass.
class Label < ActiveRecord::Base acts_as_label end
class BillingFrequency < Label
self.default
BillingFrequency.monthly
end
end
The extension also allows records to be access by system label as though the system label were a class method. The default option can be accessed in a similar manner using the class method default. This yields more expressive code.
class Role < ActiveRecord::Base has_many :users acts_as_label :default => :guest end class User < ActiveRecord::Base belongs_to :role end Role.create!({ :system_label => "SUPERUSER", :label => "Superuser"} ) Role.create!({ :system_label => "GUEST", :label => "Guest"} ) User.create!({ :name => "John Dugan", :role => Role.superuser }) User.create!({ :name => "Anonymous Dude", :role => Role.default })
To help avoid excessive querying, the extension overrides the equality operator. This allows record comparisons in a couple of formats:
u.role == Role.superuser # as you would expect u.role == :superuser # to spare a superfluous query (same as u.role.to_sym == :superuser)
Other useful utility methods:
to_s-
Returns the friendly label value
to_sym-
Returns the downcased, symbolized system label value
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Repository: github.com/coroutine/acts_as_label
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Authors: coroutine.com
Install me from RubyGems.org by adding a gem dependency to your Gemfile. Bundler does the rest.
gem “acts_as_label”
$ bundle install
Install me from RubyGems.org and add a gem dependency in the appropriate file.
$ gem install acts_as_label
Or install me as a plugin.
$ script/plugin install git://github.com/coroutine/acts_as_label.git
Other gems by Coroutine include:
Copyright © 2010 Coroutine LLC.
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