discourse/app/models/draft_sequence.rb
Sam Saffron a29ae17d3a
FIX: saving drafts unconditionally increases sequence
Previously we only changed sequence on ownership change, this
cause a race condition between tabs where user could type for a
long time without being warned of an out of date draft.

This change is a radical change and we should watch closely.

Code was already in place to track sequence on the client so no
changes are needed there.
2020-05-12 16:55:42 +10:00

57 lines
1.5 KiB
Ruby

# frozen_string_literal: true
class DraftSequence < ActiveRecord::Base
def self.next!(user, key)
user_id = user
user_id = user.id unless user.is_a?(Integer)
return 0 if invalid_user_id?(user_id)
h = { user_id: user_id, draft_key: key }
c = DraftSequence.find_by(h)
c ||= DraftSequence.new(h)
c.sequence ||= 0
c.sequence += 1
c.save!
DB.exec("DELETE FROM drafts WHERE user_id = :user_id AND draft_key = :draft_key AND sequence < :sequence", draft_key: key, user_id: user_id, sequence: c.sequence)
c.sequence
end
def self.current(user, key)
return nil unless user
user_id = user
user_id = user.id unless user.is_a?(Integer)
return nil if invalid_user_id?(user_id)
# perf critical path
r, _ = DB.query_single('select sequence from draft_sequences where user_id = ? and draft_key = ?', user_id, key)
r.to_i
end
cattr_accessor :plugin_ignore_draft_sequence_callbacks
self.plugin_ignore_draft_sequence_callbacks = {}
def self.invalid_user_id?(user_id)
user_id < 0 || self.plugin_ignore_draft_sequence_callbacks.any? do |plugin, callback|
plugin.enabled? ? callback.call(user_id) : false
end
end
private_class_method :invalid_user_id?
end
# == Schema Information
#
# Table name: draft_sequences
#
# id :integer not null, primary key
# user_id :integer not null
# draft_key :string not null
# sequence :bigint not null
#
# Indexes
#
# index_draft_sequences_on_user_id_and_draft_key (user_id,draft_key) UNIQUE
#