Module: Eluvia::PaginationHandler

Extended by:
ActiveSupport::Concern
Defined in:
lib/eluvia/handlers/pagination_handler.rb

Constant Summary collapse

NOT_SET =

Sentinel distinguishing an unset max_limit: kwarg (defer to pagination_max_limit) from an explicit max_limit: nil (no ceiling for this call only, regardless of the config/method).

Object.new.freeze

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.order_by_param_name ⇒ Object

Resolves the query parameter name carrying the order_by input according to the configured API case. Exposed so callers outside this concern (e.g. request-level validators run in a before_action ahead of set_pagination) parse the exact same parameter, instead of duplicating this ternary and risking it drifting out of sync with Config.api_case.



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# File 'lib/eluvia/handlers/pagination_handler.rb', line 9

def self.order_by_param_name
  Eluvia::Base::Config.api_case == 'camel_case' ? :orderBy : :order_by
end

Instance Method Details

#pagination_max_limit ⇒ Object

Ceiling applied to limit for this controller. Override to customize (e.g. a per-resource value pulled from a resource definition). Defaults to the library-wide config.



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# File 'lib/eluvia/handlers/pagination_handler.rb', line 19

def pagination_max_limit
  Eluvia::Base::Config.max_page_limit
end

#set_pagination(default_limit: 20, default_offset: 0, default_order_by: 'created_at:asc', fallback_order_by: 'created_at:asc', force_order_by: false, max_limit: NOT_SET, disable_errors: nil, allow_meta_only_limit: true) ⇒ Object 



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# File 'lib/eluvia/handlers/pagination_handler.rb', line 23

def set_pagination(default_limit: 20, default_offset: 0, default_order_by: 'created_at:asc',
                   fallback_order_by: 'created_at:asc', force_order_by: false, max_limit: NOT_SET,
                   disable_errors: nil, allow_meta_only_limit: true)

  # Pagination
  @limit = resolve_pagination_limit(default_limit: default_limit, max_limit: max_limit,
    disable_errors: disable_errors, allow_meta_only_limit: allow_meta_only_limit)

  @offset = params[:offset] ? params[:offset].to_i : default_offset
  if @limit.zero?
    # Meta-only request (see `allow_meta_only_limit:`) - no records to page through.
    @page = 1
    @padding = 0
  else
    @page = (@offset / @limit) + 1
    @padding = @offset % @limit
  end

  # Order by
  order_by_param = Eluvia::PaginationHandler.order_by_param_name
  user_order_by = params[order_by_param].to_s.strip
  # A blank `order_by` is treated as "not supplied" (falls through to defaults/fallback)
  # rather than as a literal empty ordering, since a Kaminari scope always needs some order.
  order_by = !force_order_by && user_order_by.present? ? user_order_by : default_order_by
  order_by = "#{order_by},#{fallback_order_by}"

  @order_by = {}
  order_by.split(',').each do |entry|
    entry = entry.strip
    # `-1` keeps a trailing empty segment (e.g. `name:`) instead of Ruby's default of
    # dropping it, so it is caught below as an invalid direction rather than as a bare field.
    parts = entry.split(':', -1)
    field_name, direction = parts

    if parts.length != 2 || field_name.blank?
      raise Eluvia::Errors::UnprocessableEntity.new({
        'order_by' => I18n.t('eluvia.errors.ordering.invalid_format',
          default: 'Invalid format, expected "field_name:asc" or "field_name:desc".')
      })
    end

    unless %w[asc desc].include?(direction)
      raise Eluvia::Errors::UnprocessableEntity.new({
        "order_by__#{field_name}" => I18n.t('eluvia.errors.ordering.invalid_direction',
          default: 'Invalid order direction. Allowed values are `asc` and `desc`.')
      })
    end

    @order_by[field_name] = direction.to_sym
  end

end