Module: MultiTenant::ModelExtensionsClassMethods

Included in:
ActiveRecord::Base
Defined in:
lib/activerecord-multi-tenant/model_extensions.rb

Constant Summary collapse

DEFAULT_ID_FIELD = 
'id'.freeze

Instance Method Summary collapse

Instance Method Details

#multi_tenant(tenant_name, options = {}) ⇒ Object 



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# File 'lib/activerecord-multi-tenant/model_extensions.rb', line 5

def multi_tenant(tenant_name, options = {})
  if to_s.underscore.to_sym == tenant_name
    unless MultiTenant.with_write_only_mode_enabled?
      # This is the tenant model itself. Workaround for https://github.com/citusdata/citus/issues/687
      before_create -> { self.id ||= self.class.connection.select_value("SELECT nextval('" + [self.class.table_name, self.class.primary_key, 'seq'].join('_') + "'::regclass)") }
    end
  else
    class << self
      def scoped_by_tenant?
        true
      end

      # Allow partition_key to be set from a superclass if not already set in this class
      def partition_key
        @partition_key ||= ancestors.detect{ |k| k.instance_variable_get(:@partition_key) }
                             .try(:instance_variable_get, :@partition_key)
      end

      # Avoid primary_key errors when using composite primary keys (e.g. id, tenant_id)
      def primary_key
        return @primary_key if @primary_key

        if ::ActiveRecord::VERSION::MAJOR < 5
          @primary_key = super || DEFAULT_ID_FIELD
          return @primary_key if connection.schema_cache.columns_hash(table_name).include? @primary_key
        end

        primary_object_keys = Array.wrap(connection.schema_cache.primary_keys(table_name)) - [partition_key]

        if primary_object_keys.size == 1
          @primary_key = primary_object_keys.first
        elsif connection.schema_cache.columns_hash(table_name).include? DEFAULT_ID_FIELD
          @primary_key = DEFAULT_ID_FIELD
        else
          # table without a primary key and DEFAULT_ID_FIELD is not present in the table
          @primary_key = nil
        end
      end

      def inherited(subclass)
        super
        MultiTenant.register_multi_tenant_model(subclass.table_name, subclass) if subclass.table_name
      end
    end

    MultiTenant.register_multi_tenant_model(table_name, self) if table_name

    @partition_key = options[:partition_key] || MultiTenant.partition_key(tenant_name)
    partition_key = @partition_key

    # Create an implicit belongs_to association only if tenant class exists
    if MultiTenant.tenant_klass_defined?(tenant_name)
      belongs_to tenant_name, options.slice(:class_name, :inverse_of).merge(foreign_key: options[:partition_key])
    end

    # New instances should have the tenant set
    after_initialize Proc.new { |record|
      if MultiTenant.current_tenant_id &&
          (!record.attribute_present?(partition_key) || record.public_send(partition_key.to_sym).nil?)
        record.public_send("#{partition_key}=".to_sym, MultiTenant.current_tenant_id)
      end
    }

    to_include = Module.new do
      define_method "#{partition_key}=" do |tenant_id|
        write_attribute("#{partition_key}", tenant_id)

        # Rails 5 `attribute_will_change!` uses the attribute-method-call rather than `read_attribute`
        # and will raise ActiveModel::MissingAttributeError if that column was not selected.
        # This is rescued as NoMethodError and in MRI attribute_was is assigned an arbitrary Object
        # This is still true after the Rails 5.2 refactor
        was = send("#{partition_key}_was")
        was_nil_or_skipped = was.nil? || was.class == Object

        raise MultiTenant::TenantIsImmutable if send("#{partition_key}_changed?") && persisted? && !was_nil_or_skipped
        tenant_id
      end

      if MultiTenant.tenant_klass_defined?(tenant_name)
        define_method "#{tenant_name}=" do |model|
          super(model)
          raise MultiTenant::TenantIsImmutable if send("#{partition_key}_changed?") && persisted? && !send("#{partition_key}_was").nil?
          model
        end

        define_method "#{tenant_name}" do
          if !association(tenant_name.to_sym).loaded? && !MultiTenant.current_tenant_is_id? && MultiTenant.current_tenant_id && public_send(partition_key) == MultiTenant.current_tenant_id
            return MultiTenant.current_tenant
          else
            super()
          end
        end
      end
    end
    include to_include

    around_save -> (record, block) {
      if persisted? && MultiTenant.current_tenant_id.nil?
        MultiTenant.with(record.public_send(partition_key)) { block.call }
      else
        block.call
      end
    }

    around_update -> (record, block) {
      if MultiTenant.current_tenant_id.nil?
        MultiTenant.with(record.public_send(partition_key)) { block.call }
      else
        block.call
      end
    }

    around_destroy -> (record, block) {
      if MultiTenant.current_tenant_id.nil?
        MultiTenant.with(record.public_send(partition_key)) { block.call }
      else
        block.call
      end
    }
  end
end