module Ballast::Concerns::JSONApi::PaginationHandling

A concern to handle errors. It requires the Ajax concern.

Public Instance Methods

paginate(collection, sort_field: :id, sort_order: :desc) click to toggle source

Paginates a collection.

@param collection [ActiveRecord::Relation] The collection to handle. @param sort_field [Symbol] The field to sort on. @param sort_order [Symbol] The sorting order. return [ActiveRecord::Relation] A paginated and sorted collection.

# File lib/ballast/concerns/json_api/pagination_handling.rb, line 17
def paginate(collection, sort_field: :id, sort_order: :desc)
  direction = @cursor.direction
  value = @cursor.value

  # Apply the query
  collection = apply_value(collection, value, sort_field, sort_order)
  collection = collection.limit(@cursor.size).order(sprintf("%s %s", sort_field, sort_order.upcase))

  # If we're fetching previous we reverse the order to make sure we fetch the results adiacents to the previous request,
  # then we reverse results to ensure the order requested
  if direction != "next"
    collection = collection.reverse_order
    collection = collection.reverse
  end

  collection
end
pagination_field() click to toggle source

Returns the field used for pagination.

@return [Symbol] The field used for pagination.

# File lib/ballast/concerns/json_api/pagination_handling.rb, line 38
def pagination_field
  @pagination_field ||= :id
end
pagination_skip?() click to toggle source

Returns whether pagination should be skipped in templates rendering for JSON API.

@return [Boolean] Whether pagination should be skipped.

# File lib/ballast/concerns/json_api/pagination_handling.rb, line 45
def pagination_skip?
  @skip_pagination
end
pagination_supported?() click to toggle source

Returns whether pagination is supported for the current set of objects for JSON API.

@return [Boolean] Whether pagination is supported.

# File lib/ballast/concerns/json_api/pagination_handling.rb, line 52
def pagination_supported?
  @objects.respond_to?(:first) && @objects.respond_to?(:last)
end
pagination_url(key = nil) click to toggle source

Returns a URL to get a specific page of the current set of objects.

@param key [String] The page to get. Supported values are `next`, `prev`, `previous` and `first`. @return [String] A URL.

# File lib/ballast/concerns/json_api/pagination_handling.rb, line 60
def pagination_url(key = nil)
  exist = @cursor.might_exist?(key, @objects)
  exist ? url_for(request.params.merge(page: @cursor.save(@objects, key, field: pagination_field)).merge(only_path: false)) : nil
end