hometown/app/models/concerns/paginable.rb
Akihiko Odaki ae871c4d46
Make Array-creation behavior of Paginable more predictable (#14687)
* Make Array-creation behavior of Paginable more predictable

Paginable.paginate_by_id usually returns ActiveRecord::Relation, but it
returns an Array if min_id option is present. The behavior caused problems
fixed with the following commits:
- 552e886b64
- b63ede5005
- 64ef37b89d

To prevent from recurring similar problems, this commit introduces two
changes:
- The scope now always returns an Array whether min_id option is present
  or not.
- The scope is renamed to to_a_paginated_by_id to clarify it returns an
  Array.

* Transform Paginable.to_a_paginated_by_id from a scope to a class method

https://api.rubyonrails.org/classes/ActiveRecord/Scoping/Named/ClassMethods.html#method-i-scope
> The method is intended to return an ActiveRecord::Relation object, which
> is composable with other scopes.

Paginable.to_a_paginated_by_id returns an Array and is not appropriate
as a scope.
2020-08-31 12:47:09 +02:00

32 lines
1.1 KiB
Ruby

# frozen_string_literal: true
module Paginable
extend ActiveSupport::Concern
included do
scope :paginate_by_max_id, ->(limit, max_id = nil, since_id = nil) {
query = order(arel_table[:id].desc).limit(limit)
query = query.where(arel_table[:id].lt(max_id)) if max_id.present?
query = query.where(arel_table[:id].gt(since_id)) if since_id.present?
query
}
# Differs from :paginate_by_max_id in that it gives the results immediately following min_id,
# whereas since_id gives the items with largest id, but with since_id as a cutoff.
# Results will be in ascending order by id.
scope :paginate_by_min_id, ->(limit, min_id = nil) {
query = reorder(arel_table[:id]).limit(limit)
query = query.where(arel_table[:id].gt(min_id)) if min_id.present?
query
}
def self.to_a_paginated_by_id(limit, options = {})
if options[:min_id].present?
paginate_by_min_id(limit, options[:min_id]).reverse
else
paginate_by_max_id(limit, options[:max_id], options[:since_id]).to_a
end
end
end
end