Module: ViewModel::Controller::MigrationVersions

Extended by:
ActiveSupport::Concern
Included in:
ActiveRecord::Controller
Defined in:
lib/view_model/controller/migration_versions.rb

Constant Summary collapse

MIGRATION_VERSION_HEADER = 
'X-ViewModel-Versions'

Instance Method Summary collapse

Instance Method Details

#migration_versions ⇒ Object 



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# File 'lib/view_model/controller/migration_versions.rb', line 8

def migration_versions
  @migration_versions ||=
    begin
      versions = specified_migration_versions.dup

      unless ViewModel::Config.strict_migration_versions
        # Ignore the current version. This allows skipping migrations if only
        # current versions are requested. Can't be ignored when strict
        # migrations are enabled, since we need to walk the tree to assert
        # that all visited types are mentioned.
        versions.reject! do |viewmodel_class, required_version|
          viewmodel_class.schema_version == required_version
        end
      end

      versions.freeze
    end
end

#specified_migration_versions ⇒ Object 



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# File 'lib/view_model/controller/migration_versions.rb', line 27

def specified_migration_versions
  @specified_migration_versions ||=
    begin
      version_spec =
        if params.include?(:versions)
          params[:versions]
        elsif request.headers.include?(MIGRATION_VERSION_HEADER)
          begin
            JSON.parse(request.headers[MIGRATION_VERSION_HEADER])
          rescue JSON::ParserError
            raise ViewModel::Error.new(status: 400, detail: "Invalid JSON in #{MIGRATION_VERSION_HEADER}")
          end
        else
          {}
        end

      versions =
        IknowParams::Parser.parse_value(
          version_spec,
          with: IknowParams::Serializer::HashOf.new(
            IknowParams::Serializer::String, IknowParams::Serializer::Integer))

      migration_versions = {}

      versions.each do |view_name, required_version|
        viewmodel_class = ViewModel::Registry.for_view_name(view_name)
        migration_versions[viewmodel_class] = required_version
      rescue ViewModel::DeserializationError::UnknownView
        # Ignore requests to migrate types that no longer exist
        next
      end

      migration_versions.freeze
    end
end