Module: JSONAPIonify::Api::Resource::Definitions::Pagination

Defined in:
lib/jsonapionify/api/resource/definitions/pagination.rb

Defined Under Namespace

Modules: InstanceMethods Classes: PaginationLinksDelegate

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.extended(klass) ⇒ Object 



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# File 'lib/jsonapionify/api/resource/definitions/pagination.rb', line 22

def self.extended(klass)
  klass.class_eval do
    include InstanceMethods

    inherited_hash_attribute :pagination_strategies

    define_pagination_strategy 'Object' do |collection|
      collection
    end

    define_pagination_strategy 'Enumerable' do |collection, params, links, per, context|
      size = Integer(params['first'] || params['last'] || per)

      slice =
        if (params['before'] && params['first']) || (params['after'] && params['last'])
          error :forbidden do
            detail 'Illegal combination of parameters'
          end
        elsif (after = params['after'])
          key_values = parse_and_validate_cursor(:after, after, context)
          array_select_past_cursor(collection, context.sort_params, key_values).first(size)
        elsif (before = params['before'])
          key_values = parse_and_validate_cursor(:before, before, context)
          array_select_past_cursor(collection, context.sort_params.invert, key_values).last(size)
        elsif params['last']
          collection.last(size)
        else
          collection.first(size)
        end

      context.meta[:total_count] = collection.count

      links.first first: size
      links.last last: size
      links.prev before: build_cursor(context: context, instance: slice.first), last: size unless !slice.first || slice.first == collection.first
      links.next after: build_cursor(context: context, instance: slice.last), first: size unless !slice.last || slice.last == collection.last

      slice
    end

    define_pagination_strategy 'ActiveRecord::Relation' do |collection, params, links, per, context|
      size = Integer(params['first'] || params['last'] || per)

      slice =
        if (params['before'] && params['first']) || (params['after'] && params['last'])
          error :forbidden do
            detail 'Illegal combination of parameters'
          end
        elsif (after = params['after'])
          key_values = parse_and_validate_cursor(:after, after, context)
          arel_select_past_cursor(collection, context.sort_params, key_values).limit(size)
        elsif (before = params['before'])
          key_values = parse_and_validate_cursor(:before, before, context)
          ids        = arel_select_past_cursor(collection, context.sort_params.invert, key_values)
                         .reverse_order.limit(size).pluck(id_attribute)
          collection.where(id_attribute => ids)
        elsif params['last']
          ids = collection.reverse_order.limit(size).pluck(id_attribute)
          collection.where(id_attribute => ids).limit(size)
        else
          collection.limit(size)
        end

      context.meta[:total_count] = collection.count

      links.first first: size
      links.last last: size
      links.prev before: build_cursor(context: context, instance: slice.first), last: size unless !slice.first || slice.first == collection.first
      links.next after: build_cursor(context: context, instance: slice.last), first: size unless !slice.last || slice.last == collection.last

      slice
    end
  end
end

Instance Method Details

#define_pagination_strategy(mod, &block) ⇒ Object 



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# File 'lib/jsonapionify/api/resource/definitions/pagination.rb', line 97

def define_pagination_strategy(mod, &block)
  pagination_strategies[mod.to_s] = block
end

#enable_pagination(per: 50) ⇒ Object 



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# File 'lib/jsonapionify/api/resource/definitions/pagination.rb', line 101

def enable_pagination(per: 50)
  param :page, :after, actions: %i{list}
  param :page, :before, actions: %i{list}
  param :page, :first, actions: %i{list}
  param :page, :last, actions: %i{list}
  context :paginated_collection, readonly: true do |context, nested_request: false, sorted_collection:, collection:, request:, params:, links:|
    if !nested_request
      collection = sorted_collection
      _, block   = pagination_strategies.to_a.reverse.to_h.find do |mod, _|
        Object.const_defined?(mod, false) && collection.class <= Object.const_get(mod, false)
      end

      links_delegate = PaginationLinksDelegate.new(request.url, params, links)

      instance_exec(
        collection,
        request.params['page'] || {},
        links_delegate,
        per,
        context,
        &block
      )
    else
      collection
    end
  end
end