class MigratePollsData < ActiveRecord::Migration[5.2] def escape(text) PG::Connection.escape_string(text) end POLL_TYPES ||= { "regular" => 0, "multiple" => 1, "number" => 2, } PG_INTEGER_MAX ||= 2_147_483_647 def up # Ensure we don't have duplicate polls DB.exec <<~SQL WITH duplicates AS ( SELECT id, row_number() OVER (PARTITION BY post_id) r FROM post_custom_fields WHERE name = 'polls' ORDER BY created_at ) DELETE FROM post_custom_fields WHERE id IN (SELECT id FROM duplicates WHERE r > 1) SQL # Ensure we don't have duplicate votes DB.exec <<~SQL WITH duplicates AS ( SELECT id, row_number() OVER (PARTITION BY post_id) r FROM post_custom_fields WHERE name = 'polls-votes' ORDER BY created_at ) DELETE FROM post_custom_fields WHERE id IN (SELECT id FROM duplicates WHERE r > 1) SQL # Ensure we have votes records DB.exec <<~SQL INSERT INTO post_custom_fields (post_id, name, value, created_at, updated_at) SELECT post_id, 'polls-votes', '{}', created_at, updated_at FROM post_custom_fields WHERE name = 'polls' AND post_id NOT IN (SELECT post_id FROM post_custom_fields WHERE name = 'polls-votes') SQL sql = <<~SQL SELECT polls.post_id , polls.created_at , polls.updated_at , polls.value::json "polls" , votes.value::json "votes" FROM post_custom_fields polls JOIN post_custom_fields votes ON polls.post_id = votes.post_id WHERE polls.name = 'polls' AND votes.name = 'polls-votes' ORDER BY polls.post_id SQL DB.query(sql).each do |r| # for some reasons, polls or votes might be an array r.polls = r.polls[0] if Array === r.polls && r.polls.size > 0 r.votes = r.votes[0] if Array === r.votes && r.votes.size > 0 existing_user_ids = User.where(id: r.votes.keys).pluck(:id).to_set # Poll votes are stored in a JSON object with the following hierarchy # user_id -> poll_name -> options # Since we're iterating over polls, we need to change the hierarchy to # poll_name -> user_id -> options votes = {} r.votes.each do |user_id, user_votes| # don't migrate votes from deleted/non-existing users next unless existing_user_ids.include?(user_id.to_i) user_votes.each do |poll_name, options| votes[poll_name] ||= {} votes[poll_name][user_id] = options end end r.polls.values.each do |poll| name = poll["name"].presence || "poll" type = POLL_TYPES[(poll["type"].presence || "")[/(regular|multiple|number)/, 1] || "regular"] status = poll["status"] == "open" ? 0 : 1 visibility = poll["public"] == "true" ? 1 : 0 close_at = (Time.zone.parse(poll["close"]) rescue nil) min = poll["min"].to_i.clamp(0, PG_INTEGER_MAX) max = poll["max"].to_i.clamp(0, PG_INTEGER_MAX) step = poll["step"].to_i.clamp(0, max) anonymous_voters = poll["anonymous_voters"].to_i.clamp(0, PG_INTEGER_MAX) poll_id = execute(<<~SQL INSERT INTO polls ( post_id, name, type, status, visibility, close_at, min, max, step, anonymous_voters, created_at, updated_at ) VALUES ( #{r.post_id}, '#{escape(name)}', #{type}, #{status}, #{visibility}, #{close_at ? "'#{close_at}'" : "NULL"}, #{min > 0 ? min : "NULL"}, #{max > min ? max : "NULL"}, #{step > 0 ? step : "NULL"}, #{anonymous_voters > 0 ? anonymous_voters : "NULL"}, '#{r.created_at}', '#{r.updated_at}' ) RETURNING id SQL )[0]["id"] option_ids = Hash[*DB.query_single(<<~SQL INSERT INTO poll_options (poll_id, digest, html, anonymous_votes, created_at, updated_at) VALUES #{poll["options"].map { |option| "(#{poll_id}, '#{escape(option["id"])}', '#{escape(option["html"].strip)}', #{option["anonymous_votes"].to_i}, '#{r.created_at}', '#{r.updated_at}')" }.join(",") } RETURNING digest, id SQL )] if votes[name].present? poll_votes = votes[name].map do |user_id, options| options .select { |o| option_ids.has_key?(o) } .map { |o| "(#{poll_id}, #{option_ids[o]}, #{user_id.to_i}, '#{r.created_at}', '#{r.updated_at}')" } end poll_votes.flatten! poll_votes.uniq! if poll_votes.present? execute <<~SQL INSERT INTO poll_votes (poll_id, poll_option_id, user_id, created_at, updated_at) VALUES #{poll_votes.join(",")} SQL end end end end execute <<~SQL INSERT INTO post_custom_fields (name, value, post_id, created_at, updated_at) SELECT 'has_polls', 't', post_id, MIN(created_at), MIN(updated_at) FROM polls GROUP BY post_id SQL end def down end end