Class: Tush::Importer

Inherits:
Object
  • Object
show all
Defined in:
lib/tush/importer.rb

Overview

This class takes in a tush export and imports it into ActiveRecord.

Defined Under Namespace

Classes: InvalidWrapperError, NonUniqueWrapperError

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(exported_data) ⇒ Importer

Returns a new instance of Importer.



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# File 'lib/tush/importer.rb', line 16

def initialize(exported_data)
  self.data = exported_data
  self.imported_model_wrappers = []
  self.model_to_attribute_blacklist = {}
end

Instance Attribute Details

#data ⇒ Object

Returns the value of attribute data.



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# File 'lib/tush/importer.rb', line 12

def data
  @data
end

#imported_model_wrappers ⇒ Object

Returns the value of attribute imported_model_wrappers.



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# File 'lib/tush/importer.rb', line 12

def imported_model_wrappers
  @imported_model_wrappers
end

#model_to_attribute_blacklist ⇒ Object

Returns the value of attribute model_to_attribute_blacklist.



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# File 'lib/tush/importer.rb', line 12

def model_to_attribute_blacklist
  @model_to_attribute_blacklist
end

Class Method Details

.new_from_json(unparsed_json) ⇒ Object 



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# File 'lib/tush/importer.rb', line 27

def self.new_from_json(unparsed_json)
  self.new(JSON.parse(unparsed_json))
end

.new_from_json_file(json_path) ⇒ Object 



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# File 'lib/tush/importer.rb', line 22

def self.new_from_json_file(json_path)
  unparsed_json = File.read(json_path)
  self.new(JSON.parse(unparsed_json))
end

Instance Method Details

#create_models! ⇒ Object 



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# File 'lib/tush/importer.rb', line 31

def create_models!
  model_wrappers = self.data["model_wrappers"]

  model_wrappers.each do |model_wrapper|
    model_class = model_wrapper["model_class"].constantize
    imported_model_wrapper =
      ModelWrapper.new(:model_class => model_class.to_s,
                       :model_attributes => model_wrapper["model_attributes"],
                       :blacklisted_attributes => self.model_to_attribute_blacklist[model_class])

    imported_model_wrapper.create_copy

    self.imported_model_wrappers << imported_model_wrapper
  end
end

#find_wrapper_by_class_and_old_id(klass, old_id) ⇒ Object 



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# File 'lib/tush/importer.rb', line 47

def find_wrapper_by_class_and_old_id(klass, old_id)
  wrappers = self.imported_model_wrappers.select do |wrapper|
    (wrapper.model_class == klass) and (wrapper.original_db_id == old_id)
  end

  wrappers[0]
end

#update_foreign_keys! ⇒ Object

This method updates stale foreign keys after the new models have been created.



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# File 'lib/tush/importer.rb', line 56

def update_foreign_keys!
  models = self.imported_model_wrappers.map { |wrapper| wrapper.model_class }
  model_to_foreign_keys = AssociationHelpers.create_foreign_key_mapping(models)

  imported_model_wrappers.each do |wrapper|
    foreign_keys = model_to_foreign_keys[wrapper.model_class]

    foreign_keys.each do |foreign_key_info|
      match = self.find_wrapper_by_class_and_old_id(foreign_key_info[:class],
                                                    wrapper.model_attributes[foreign_key_info[:foreign_key]])

      if match
        new_id = match.new_model.send(match.original_db_key)
      else
        # If we don't have a model wrapper (like in the case of a copy only model),
        # remove the id
        new_id = nil
      end

      ActiveRecord::Base.transaction(:requires_new => true) do
        begin
          wrapper.new_model.update_column(foreign_key_info[:foreign_key],
                                          new_id)
        # If the column has a not null restraint, keep the original value
        rescue ActiveRecord::StatementInvalid
          raise ActiveRecord::Rollback
        end

        wrapper.new_model_attributes[foreign_key_info[:foreign_key]] = new_id
      end
    end
  end
end