record_identifier.rb

   1 module ActionController
   2   # The record identifier encapsulates a number of naming conventions for dealing with records, like Active Records or
   3   # Active Resources or pretty much any other model type that has an id. These patterns are then used to try elevate
   4   # the view actions to a higher logical level. Example:
   5   #
   6   #   # routes
   7   #   map.resources :posts
   8   #
   9   #   # view
  10   #   <% div_for(post) do %>     <div id="post_45" class="post">
  11   #     <%= post.body %>           What a wonderful world!
  12   #   <% end %>                  </div>
  13   #
  14   #   # controller
  15   #   def destroy
  16   #     post = Post.find(params[:id])
  17   #     post.destroy
  18   #
  19   #     respond_to do |format|
  20   #       format.html { redirect_to(post) } # Calls polymorphic_url(post) which in turn calls post_url(post)
  21   #       format.js do
  22   #         # Calls: new Effect.fade('post_45');
  23   #         render(:update) { |page| page[post].visual_effect(:fade) }
  24   #       end
  25   #     end
  26   #   end
  27   #
  28   # As the example above shows, you can stop caring to a large extent what the actual id of the post is. You just know
  29   # that one is being assigned and that the subsequent calls in redirect_to and the RJS expect that same naming
  30   # convention and allows you to write less code if you follow it.
  31   module RecordIdentifier
  32     extend self
  33
  34     JOIN = '_'.freeze
  35     NEW = 'new'.freeze
  36
  37     # Returns plural/singular for a record or class. Example:
  38     #
  39     #   partial_path(post)                   # => "posts/post"
  40     #   partial_path(Person)                 # => "people/person"
  41     #   partial_path(Person, "admin/games")  # => "admin/people/person"
  42     def partial_path(record_or_class, controller_path = nil)
  43       name = model_name_from_record_or_class(record_or_class)
  44
  45       if controller_path && controller_path.include?("/")
  46         "#{File.dirname(controller_path)}/#{name.partial_path}"
  47       else
  48         name.partial_path
  49       end
  50     end
  51
  52     # The DOM class convention is to use the singular form of an object or class. Examples:
  53     #
  54     #   dom_class(post)   # => "post"
  55     #   dom_class(Person) # => "person"
  56     #
  57     # If you need to address multiple instances of the same class in the same view, you can prefix the dom_class:
  58     #
  59     #   dom_class(post, :edit)   # => "edit_post"
  60     #   dom_class(Person, :edit) # => "edit_person"
  61     def dom_class(record_or_class, prefix = nil)
  62       singular = singular_class_name(record_or_class)
  63       prefix ? "#{prefix}#{JOIN}#{singular}" : singular
  64     end
  65
  66     # The DOM id convention is to use the singular form of an object or class with the id following an underscore.
  67     # If no id is found, prefix with "new_" instead. Examples:
  68     #
  69     #   dom_id(Post.find(45))       # => "post_45"
  70     #   dom_id(Post.new)            # => "new_post"
  71     #
  72     # If you need to address multiple instances of the same class in the same view, you can prefix the dom_id:
  73     #
  74     #   dom_id(Post.find(45), :edit) # => "edit_post_45"
  75     def dom_id(record, prefix = nil)
  76       if record_id = record.id
  77         "#{dom_class(record, prefix)}#{JOIN}#{record_id}"
  78       else
  79         dom_class(record, prefix || NEW)
  80       end
  81     end
  82
  83     # Returns the plural class name of a record or class. Examples:
  84     #
  85     #   plural_class_name(post)             # => "posts"
  86     #   plural_class_name(Highrise::Person) # => "highrise_people"
  87     def plural_class_name(record_or_class)
  88       model_name_from_record_or_class(record_or_class).plural
  89     end
  90
  91     # Returns the singular class name of a record or class. Examples:
  92     #
  93     #   singular_class_name(post)             # => "post"
  94     #   singular_class_name(Highrise::Person) # => "highrise_person"
  95     def singular_class_name(record_or_class)
  96       model_name_from_record_or_class(record_or_class).singular
  97     end
  98
  99     private
 100       def model_name_from_record_or_class(record_or_class)
 101         (record_or_class.is_a?(Class) ? record_or_class : record_or_class.class).model_name
 102       end
 103   end
 104 end