Module: Replicate::AR::ClassMethods

Defined in:
lib/replicate/active_record.rb

Overview

Mixin for the ActiveRecord class.

Instance Method Summary collapse

Instance Method Details

#create_or_update_replicant(instance, attributes) ⇒ Object

Update an AR object’s attributes and persist to the database without running validations or callbacks.

Returns the [id, object] tuple for the newly replicated objected.



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# File 'lib/replicate/active_record.rb', line 176

def create_or_update_replicant(instance, attributes)
  # write replicated attributes to the instance
  attributes.each do |key, value|
    next if key == primary_key and not replicate_id
    instance.send :write_attribute, key, value
  end

  # save the instance bypassing all callbacks and validations
  replicate_disable_callbacks instance
  if ::ActiveRecord::VERSION::MAJOR >= 3
    instance.save :validate => false
  else
    instance.save false
  end

  [instance.id, instance]
end

#load_replicant(type, id, attributes) ⇒ Object

Load an individual record into the database. If the models defines a replicate_natural_key then an existing record will be updated if found instead of a new record being created.

type - Model class name as a String. id - Primary key id of the record on the dump system. This must be

translated to the local system and stored in the keymap.

attrs - Hash of attributes to set on the new record.

Returns the ActiveRecord object instance for the new record.



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# File 'lib/replicate/active_record.rb', line 154

def load_replicant(type, id, attributes)
  instance = replicate_find_existing_record(attributes) || new
  create_or_update_replicant instance, attributes
end

#replicate_associations(*names) ⇒ Object

Set and retrieve list of association names that should be dumped when objects of this class are dumped. This method may be called multiple times to add associations.



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# File 'lib/replicate/active_record.rb', line 105

def replicate_associations(*names)
  self.replicate_associations += names if names.any?
  @replicate_associations || superclass.replicate_associations
end

#replicate_associations=(names) ⇒ Object

Set the list of association names to dump to the specific set of values.



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# File 'lib/replicate/active_record.rb', line 111

def replicate_associations=(names)
  @replicate_associations = names.uniq.map { |name| name.to_sym }
end

#replicate_disable_callbacks(instance) ⇒ Object

Disable all callbacks on an ActiveRecord::Base instance. Only the instance is effected. There is no way to re-enable callbacks once they’ve been disabled on an object.



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# File 'lib/replicate/active_record.rb', line 197

def replicate_disable_callbacks(instance)
  if ::ActiveRecord::VERSION::MAJOR >= 3
    # AR 3.1.x
    def instance.run_callbacks(*args); yield; end

    # AR 3.0.x
    def instance._run_save_callbacks(*args); yield; end
    def instance._run_create_callbacks(*args); yield; end
    def instance._run_update_callbacks(*args); yield; end
  else
    # AR 2.x
    def instance.callback(*args)
    end
    def instance.record_timestamps
      false
    end
  end
end

#replicate_find_existing_record(attributes) ⇒ Object

Locate an existing record using the replicate_natural_key attribute values.

Returns the existing record if found, nil otherwise.



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# File 'lib/replicate/active_record.rb', line 163

def replicate_find_existing_record(attributes)
  return if replicate_natural_key.empty?
  conditions = {}
  replicate_natural_key.each do |attribute_name|
    conditions[attribute_name] = attributes[attribute_name.to_s]
  end
  find(:first, :conditions => conditions)
end

#replicate_id(boolean = nil) ⇒ Object

Set or retrieve whether replicated object should keep its original id. When not set, replicated objects will be created with new id.



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# File 'lib/replicate/active_record.rb', line 134

def replicate_id(boolean=nil)
  self.replicate_id = boolean unless boolean.nil?
  @replicate_id.nil? ? superclass.replicate_id : @replicate_id
end

#replicate_id=(boolean) ⇒ Object

Set flag for replicating original id.



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# File 'lib/replicate/active_record.rb', line 140

def replicate_id=(boolean)
  @replicate_id = boolean
end

#replicate_natural_key(*attribute_names) ⇒ Object

Compound key used during load to locate existing objects for update. When no natural key is defined, objects are created new.

attribute_names - Macro style setter.



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# File 'lib/replicate/active_record.rb', line 119

def replicate_natural_key(*attribute_names)
  self.replicate_natural_key = attribute_names if attribute_names.any?
  @replicate_natural_key || superclass.replicate_natural_key
end

#replicate_natural_key=(attribute_names) ⇒ Object

Set the compound key used to locate existing objects for update when loading. When not set, loading will always create new records.

attribute_names - Array of attribute name symbols



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# File 'lib/replicate/active_record.rb', line 128

def replicate_natural_key=(attribute_names)
  @replicate_natural_key = attribute_names
end