Module: Secretary::TracksAssociation::ClassMethods

Defined in:
lib/secretary/tracks_association.rb

Instance Method Summary collapse

Instance Method Details

#tracks_association(*associations) ⇒ Object

Track the associations passed-in This will make sure that when you change the association, the saved record will get a new version, with association diffs and everything.

Arguments

associations - (Symbols) A variable number of association

names to track

Example

has_secretary

has_many :bylines,
  :as           => :content,
  :class_name   => "ContentByline",
  :dependent    => :destroy

tracks_association :bylines

If you want to control when an association should be left out of the version, define an instance method named ‘should_reject_#name?`. This method takes a hash of the model’s attributes (so you can pass in, for example, form params). This also lets you easily share this method with ‘accepts_nested_attributes_for`.

Example

class Person < ActiveRecord::Base
  has_secretary
  has_many :animals
  tracks_association :animals

  accepts_nested_attributes_for :animals,
    :reject_if => :should_reject_animals?

  private

  def should_reject_animals?(attributes)
    attributes['name'].blank?
  end
end

Returns nothing



51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
 
# File 'lib/secretary/tracks_association.rb', line 51

def tracks_association(*associations)
  if !self.has_secretary?
    raise NotVersionedError, self.name
  end

  include DirtyAssociations

  associations.each do |name|
    reflection = self.reflect_on_association(name)

    if !reflection
      raise NoAssociationError, name, self.name
    end

    # If the environment is loaded, the following line will be
    # evaluated for any `tracks_association` calls.
    # `versioned_attributes` calls `self.column_names`,
    # which requires the table to exist.
    #
    # So the problem is that if our database or table doesn't exist,
    # we can't load the environment, and the environment needs to be
    # loaded in order to load in the schema.
    #
    # So, we rescue! And warn.
    begin
      self.versioned_attributes << name.to_s

      if reflection.macro == :belongs_to
        self.versioned_attributes << reflection.foreign_key
      end

    rescue => e
      warn  "[secretary-rails] Caught an error while loading " \
            "#{self.name}. #{e}"
    end

    define_dirty_association_methods(name, reflection)

    if reflection.collection?
      include DirtyAssociations::Collection
      add_collection_callbacks(name, reflection)
    else
      include DirtyAssociations::Singular
      define_singular_association_writer(name)
    end
  end
end