258 lines
8.2 KiB
Ruby
258 lines
8.2 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
module API
|
|
module Helpers
|
|
module Pagination
|
|
def paginate(relation)
|
|
strategy = if params[:pagination] == 'keyset' && Feature.enabled?('api_keyset_pagination')
|
|
KeysetPaginationStrategy
|
|
else
|
|
DefaultPaginationStrategy
|
|
end
|
|
|
|
strategy.new(self).paginate(relation)
|
|
end
|
|
|
|
class Base
|
|
private
|
|
|
|
def per_page
|
|
@per_page ||= params[:per_page]
|
|
end
|
|
|
|
def base_request_uri
|
|
@base_request_uri ||= URI.parse(request.url).tap do |uri|
|
|
uri.host = Gitlab.config.gitlab.host
|
|
uri.port = Gitlab.config.gitlab.port
|
|
end
|
|
end
|
|
|
|
def build_page_url(query_params:)
|
|
base_request_uri.tap do |uri|
|
|
uri.query = query_params
|
|
end.to_s
|
|
end
|
|
|
|
def page_href(next_page_params = {})
|
|
query_params = params.merge(**next_page_params, per_page: per_page).to_query
|
|
|
|
build_page_url(query_params: query_params)
|
|
end
|
|
end
|
|
|
|
class KeysetPaginationInfo
|
|
attr_reader :relation, :request_context
|
|
|
|
def initialize(relation, request_context)
|
|
# This is because it's rather complex to support multiple values with possibly different sort directions
|
|
# (and we don't need this in the API)
|
|
if relation.order_values.size > 1
|
|
raise "Pagination only supports ordering by a single column." \
|
|
"The following columns were given: #{relation.order_values.map { |v| v.expr.name }}"
|
|
end
|
|
|
|
@relation = relation
|
|
@request_context = request_context
|
|
end
|
|
|
|
def fields
|
|
keys.zip(values).reject { |_, v| v.nil? }.to_h
|
|
end
|
|
|
|
def column_for_order_by(relation)
|
|
relation.order_values.first&.expr&.name
|
|
end
|
|
|
|
# Sort direction (`:asc` or `:desc`)
|
|
def sort
|
|
@sort ||= if order_by_primary_key?
|
|
# Default order is by id DESC
|
|
:desc
|
|
else
|
|
# API defaults to DESC order if param `sort` not present
|
|
request_context.params[:sort]&.to_sym || :desc
|
|
end
|
|
end
|
|
|
|
# Do we only sort by primary key?
|
|
def order_by_primary_key?
|
|
keys.size == 1 && keys.first == primary_key
|
|
end
|
|
|
|
def primary_key
|
|
relation.model.primary_key.to_sym
|
|
end
|
|
|
|
def sort_ascending?
|
|
sort == :asc
|
|
end
|
|
|
|
# Build hash of request parameters for a given record (relevant to pagination)
|
|
def params_for(record)
|
|
return {} unless record
|
|
|
|
keys.each_with_object({}) do |key, h|
|
|
h["ks_prev_#{key}".to_sym] = record.attributes[key.to_s]
|
|
end
|
|
end
|
|
|
|
private
|
|
|
|
# All values present in request parameters that correspond to #keys.
|
|
def values
|
|
@values ||= keys.map do |key|
|
|
request_context.params["ks_prev_#{key}".to_sym]
|
|
end
|
|
end
|
|
|
|
# All keys relevant to pagination.
|
|
# This always includes the primary key. Optionally, the `order_by` key is prepended.
|
|
def keys
|
|
@keys ||= [column_for_order_by(relation), primary_key].compact.uniq
|
|
end
|
|
end
|
|
|
|
class KeysetPaginationStrategy < Base
|
|
attr_reader :request_context
|
|
delegate :params, :header, :request, to: :request_context
|
|
|
|
def initialize(request_context)
|
|
@request_context = request_context
|
|
end
|
|
|
|
# rubocop: disable CodeReuse/ActiveRecord
|
|
def paginate(relation)
|
|
pagination = KeysetPaginationInfo.new(relation, request_context)
|
|
|
|
paged_relation = relation.limit(per_page)
|
|
|
|
if conds = conditions(pagination)
|
|
paged_relation = paged_relation.where(*conds)
|
|
end
|
|
|
|
# In all cases: sort by primary key (possibly in addition to another sort column)
|
|
paged_relation = paged_relation.order(pagination.primary_key => pagination.sort)
|
|
|
|
add_default_pagination_headers
|
|
|
|
if last_record = paged_relation.last
|
|
next_page_params = pagination.params_for(last_record)
|
|
add_navigation_links(next_page_params)
|
|
end
|
|
|
|
paged_relation
|
|
end
|
|
# rubocop: enable CodeReuse/ActiveRecord
|
|
|
|
private
|
|
|
|
def conditions(pagination)
|
|
fields = pagination.fields
|
|
|
|
return if fields.empty?
|
|
|
|
placeholder = fields.map { '?' }
|
|
|
|
comp = if pagination.sort_ascending?
|
|
'>'
|
|
else
|
|
'<'
|
|
end
|
|
|
|
[
|
|
# Row value comparison:
|
|
# (A, B) < (a, b) <=> (A < a) OR (A = a AND B < b)
|
|
# <=> A <= a AND ((A < a) OR (A = a AND B < b))
|
|
"(#{fields.keys.join(',')}) #{comp} (#{placeholder.join(',')})",
|
|
*fields.values
|
|
]
|
|
end
|
|
|
|
def add_default_pagination_headers
|
|
header 'X-Per-Page', per_page.to_s
|
|
end
|
|
|
|
def add_navigation_links(next_page_params)
|
|
header 'X-Next-Page', page_href(next_page_params)
|
|
header 'Link', link_for('next', next_page_params)
|
|
end
|
|
|
|
def link_for(rel, next_page_params)
|
|
%(<#{page_href(next_page_params)}>; rel="#{rel}")
|
|
end
|
|
end
|
|
|
|
class DefaultPaginationStrategy < Base
|
|
attr_reader :request_context
|
|
delegate :params, :header, :request, to: :request_context
|
|
|
|
def initialize(request_context)
|
|
@request_context = request_context
|
|
end
|
|
|
|
def paginate(relation)
|
|
paginate_with_limit_optimization(add_default_order(relation)).tap do |data|
|
|
add_pagination_headers(data)
|
|
end
|
|
end
|
|
|
|
private
|
|
|
|
def paginate_with_limit_optimization(relation)
|
|
pagination_data = relation.page(params[:page]).per(params[:per_page])
|
|
return pagination_data unless pagination_data.is_a?(ActiveRecord::Relation)
|
|
return pagination_data unless Feature.enabled?(:api_kaminari_count_with_limit)
|
|
|
|
limited_total_count = pagination_data.total_count_with_limit
|
|
if limited_total_count > Kaminari::ActiveRecordRelationMethods::MAX_COUNT_LIMIT
|
|
# The call to `total_count_with_limit` memoizes `@arel` because of a call to `references_eager_loaded_tables?`
|
|
# We need to call `reset` because `without_count` relies on `@arel` being unmemoized
|
|
pagination_data.reset.without_count
|
|
else
|
|
pagination_data
|
|
end
|
|
end
|
|
|
|
def add_default_order(relation)
|
|
if relation.is_a?(ActiveRecord::Relation) && relation.order_values.empty?
|
|
relation = relation.order(:id) # rubocop: disable CodeReuse/ActiveRecord
|
|
end
|
|
|
|
relation
|
|
end
|
|
|
|
def add_pagination_headers(paginated_data)
|
|
header 'X-Per-Page', paginated_data.limit_value.to_s
|
|
header 'X-Page', paginated_data.current_page.to_s
|
|
header 'X-Next-Page', paginated_data.next_page.to_s
|
|
header 'X-Prev-Page', paginated_data.prev_page.to_s
|
|
header 'Link', pagination_links(paginated_data)
|
|
|
|
return if data_without_counts?(paginated_data)
|
|
|
|
header 'X-Total', paginated_data.total_count.to_s
|
|
header 'X-Total-Pages', total_pages(paginated_data).to_s
|
|
end
|
|
|
|
def pagination_links(paginated_data)
|
|
[].tap do |links|
|
|
links << %(<#{page_href(page: paginated_data.prev_page)}>; rel="prev") if paginated_data.prev_page
|
|
links << %(<#{page_href(page: paginated_data.next_page)}>; rel="next") if paginated_data.next_page
|
|
links << %(<#{page_href(page: 1)}>; rel="first")
|
|
|
|
links << %(<#{page_href(page: total_pages(paginated_data))}>; rel="last") unless data_without_counts?(paginated_data)
|
|
end.join(', ')
|
|
end
|
|
|
|
def total_pages(paginated_data)
|
|
# Ensure there is in total at least 1 page
|
|
[paginated_data.total_pages, 1].max
|
|
end
|
|
|
|
def data_without_counts?(paginated_data)
|
|
paginated_data.is_a?(Kaminari::PaginatableWithoutCount)
|
|
end
|
|
end
|
|
end
|
|
end
|
|
end
|