debian-mirror-gitlab/lib/gitlab/pagination/keyset/request_context.rb

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2020-01-01 13:55:28 +05:30
# frozen_string_literal: true
module Gitlab
module Pagination
module Keyset
class RequestContext
attr_reader :request
DEFAULT_SORT_DIRECTION = :desc
PRIMARY_KEY = :id
# A tie breaker is added as an additional order-by column
# to establish a well-defined order. We use the primary key
# column here.
TIE_BREAKER = { PRIMARY_KEY => DEFAULT_SORT_DIRECTION }.freeze
def initialize(request)
@request = request
end
# extracts Paging information from request parameters
def page
@page ||= Page.new(order_by: order_by, per_page: params[:per_page])
end
def apply_headers(next_page)
request.header('Links', pagination_links(next_page))
end
private
def order_by
return TIE_BREAKER.dup unless params[:order_by]
order_by = { params[:order_by].to_sym => params[:sort]&.to_sym || DEFAULT_SORT_DIRECTION }
# Order by an additional unique key, we use the primary key here
order_by = order_by.merge(TIE_BREAKER) unless order_by[PRIMARY_KEY]
order_by
end
def params
@params ||= request.params
end
def lower_bounds_params(page)
page.lower_bounds.each_with_object({}) do |(column, value), params|
filter = filter_with_comparator(page, column)
params[filter] = value
end
end
def filter_with_comparator(page, column)
direction = page.order_by[column]
if direction&.to_sym == :desc
"#{column}_before"
else
"#{column}_after"
end
end
def page_href(page)
base_request_uri.tap do |uri|
uri.query = query_params_for(page).to_query
end.to_s
end
def pagination_links(next_page)
%(<#{page_href(next_page)}>; rel="next")
end
def base_request_uri
@base_request_uri ||= URI.parse(request.request.url).tap do |uri|
uri.host = Gitlab.config.gitlab.host
uri.port = Gitlab.config.gitlab.port
end
end
def query_params_for(page)
request.params.merge(lower_bounds_params(page))
end
end
end
end
end