mastodon/app/models/concerns/notification/groups.rb
2024-11-19 10:02:01 +00:00

123 lines
5.2 KiB
Ruby

# frozen_string_literal: true
module Notification::Groups
extend ActiveSupport::Concern
# `set_group_key!` needs to be updated if this list changes
GROUPABLE_NOTIFICATION_TYPES = %i(favourite reblog follow).freeze
MAXIMUM_GROUP_SPAN_HOURS = 12
def set_group_key!
return if filtered? || GROUPABLE_NOTIFICATION_TYPES.exclude?(type)
type_prefix = case type
when :favourite, :reblog
[type, target_status&.id].join('-')
when :follow
type
else
raise NotImplementedError
end
redis_key = "notif-group/#{account.id}/#{type_prefix}"
hour_bucket = activity.created_at.utc.to_i / 1.hour.to_i
# Reuse previous group if it does not span too large an amount of time
previous_bucket = redis.get(redis_key).to_i
hour_bucket = previous_bucket if hour_bucket < previous_bucket + MAXIMUM_GROUP_SPAN_HOURS
# We do not concern ourselves with race conditions since we use hour buckets
redis.set(redis_key, hour_bucket, ex: MAXIMUM_GROUP_SPAN_HOURS.hours.to_i)
self.group_key = "#{type_prefix}-#{hour_bucket}"
end
class_methods do
def paginate_groups(limit, pagination_order, grouped_types: nil)
raise ArgumentError unless %i(asc desc).include?(pagination_order)
query = reorder(id: pagination_order)
# Ideally `:types` would be a bind rather than part of the SQL itself, but that does not
# seem to be possible to do with Rails, considering that the expression would occur in
# multiple places, including in a `select`
group_key_sql = begin
if grouped_types.present?
# Normalize `grouped_types` so the number of different SQL query shapes remains small, and
# the queries can be analyzed in monitoring/telemetry tools
grouped_types = (grouped_types.map(&:to_sym) & GROUPABLE_NOTIFICATION_TYPES).sort
sanitize_sql_array([<<~SQL.squish, { types: grouped_types }])
COALESCE(
CASE
WHEN notifications.type IN (:types) THEN notifications.group_key
ELSE NULL
END,
'ungrouped-' || notifications.id
)
SQL
else
"COALESCE(notifications.group_key, 'ungrouped-' || notifications.id)"
end
end
unscoped
.with_recursive(
grouped_notifications: [
# Base case: fetching one notification and annotating it with visited groups
query
.select('notifications.*', "ARRAY[#{group_key_sql}] AS groups")
.limit(1),
# Recursive case, always yielding at most one annotated notification
unscoped
.from(
[
# Expose the working table as `wt`, but quit early if we've reached the limit
unscoped
.select('id', 'groups')
.from('grouped_notifications')
.where('array_length(grouped_notifications.groups, 1) < :limit', limit: limit)
.arel.as('wt'),
# Recursive query, using `LATERAL` so we can refer to `wt`
query
.where(pagination_order == :desc ? 'notifications.id < wt.id' : 'notifications.id > wt.id')
.where.not("#{group_key_sql} = ANY(wt.groups)")
.limit(1)
.arel.lateral('notifications'),
]
)
.select('notifications.*', "array_append(wt.groups, #{group_key_sql}) AS groups"),
]
)
.from('grouped_notifications AS notifications')
.order(id: pagination_order)
.limit(limit)
end
# This returns notifications from the request page, but with at most one notification per group.
# Notifications that have no `group_key` each count as a separate group.
def paginate_groups_by_max_id(limit, max_id: nil, since_id: nil, grouped_types: nil)
query = reorder(id: :desc)
query = query.where(id: ...(max_id.to_i)) if max_id.present?
query = query.where(id: (since_id.to_i + 1)...) if since_id.present?
query.paginate_groups(limit, :desc, grouped_types: grouped_types)
end
# Differs from :paginate_groups_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.
def paginate_groups_by_min_id(limit, max_id: nil, min_id: nil, grouped_types: nil)
query = reorder(id: :asc)
query = query.where(id: (min_id.to_i + 1)...) if min_id.present?
query = query.where(id: ...(max_id.to_i)) if max_id.present?
query.paginate_groups(limit, :asc, grouped_types: grouped_types)
end
def to_a_grouped_paginated_by_id(limit, options = {})
if options[:min_id].present?
paginate_groups_by_min_id(limit, min_id: options[:min_id], max_id: options[:max_id], grouped_types: options[:grouped_types]).reverse
else
paginate_groups_by_max_id(limit, max_id: options[:max_id], since_id: options[:since_id], grouped_types: options[:grouped_types]).to_a
end
end
end
end