FriendlyId is an add-on to Ruby's Active Record that allows you to replace ids in your URLs with strings:
# without FriendlyId http://example.com/states/4323454 # with FriendlyId http://example.com/states/washington
It requires few changes to your application code and offers flexibility, performance and a well-documented codebase.
The concept of "slugs" is at the heart of FriendlyId.
A slug is the part of a URL which identifies a page using human-readable keywords, rather than an opaque identifier such as a numeric id. This can make your application more friendly both for users and search engine.
To the extent possible, FriendlyId lets you treat text-based identifiers like normal IDs. This means that you can perform finds with slugs just like you do with numeric ids:
Person.find(82542335) Person.find("joe")
Set global defaults for all models using FriendlyId.
The default defaults are to use the :reserved module and nothing else.
@example
FriendlyId.defaults do |config| config.base = :name config.use :slugged end
# File lib/friendly_id.rb, line 104 def self.defaults(&block) @mutex.synchronize do @defaults = block if block_given? @defaults ||= lambda {|config| config.use :reserved} end end
FriendlyId takes advantage of `extended` to do basic model setup, primarily extending {FriendlyId::Base} to add {FriendlyId::Base#friendly_id friendly_id} as a class method.
Previous versions of FriendlyId simply patched ActiveRecord::Base, but this version tries to be less invasive.
In addition to adding {FriendlyId::Base#friendly_id friendly_id}, the class instance variable +@friendly_id_config+ is added. This variable is an instance of an anonymous subclass of {FriendlyId::Configuration}. This allows subsequently loaded modules like {FriendlyId::Slugged} and {FriendlyId::Scoped} to add functionality to the configuration class only for the current class, rather than monkey patching {FriendlyId::Configuration} directly. This isolates other models from large feature changes an addon to FriendlyId could potentially introduce.
The upshot of this is, you can have two Active Record models that both have a @friendly_id_config, but each config object can have different methods and behaviors depending on what modules have been loaded, without conflicts. Keep this in mind if you're hacking on FriendlyId.
For examples of this, see the source for {Scoped.included}.
# File lib/friendly_id.rb, line 78 def self.extended(model_class) return if model_class.respond_to? :friendly_id class << model_class alias relation_without_friendly_id relation end model_class.instance_eval do extend Base @friendly_id_config = Class.new(Configuration).new(self) FriendlyId.defaults.call @friendly_id_config end end
Allow developers to `include` FriendlyId or `extend` it.
# File lib/friendly_id.rb, line 91 def self.included(model_class) model_class.extend self end
Set the ActiveRecord table name prefix to friendly_id_
This makes 'slugs' into 'friendly_id_slugs' and also respects any 'global' table_name_prefix set on ActiveRecord::Base.
# File lib/friendly_id.rb, line 115 def self.table_name_prefix "#{ActiveRecord::Base.table_name_prefix}friendly_id_" end
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