lib/database_functions.rb

   1 module DatabaseFunctions
   2   API_RATE_LIMIT = %(
   3     CREATE OR REPLACE FUNCTION api_rate_limit(user_id int8)
   4       RETURNS int4
   5       AS $$
   6     DECLARE
   7       min_changes_per_hour int4 := #{Settings.min_changes_per_hour};
   8       initial_changes_per_hour int4 := #{Settings.initial_changes_per_hour};
   9       max_changes_per_hour int4 := #{Settings.max_changes_per_hour};
  10       days_to_max_changes int4 := #{Settings.days_to_max_changes};
  11       importer_changes_per_hour int4 := #{Settings.importer_changes_per_hour};
  12       moderator_changes_per_hour int4 := #{Settings.moderator_changes_per_hour};
  13       roles text[];
  14       last_block timestamp without time zone;
  15       first_change timestamp without time zone;
  16       active_reports int4;
  17       time_since_first_change double precision;
  18       max_changes double precision;
  19       recent_changes int4;
  20     BEGIN
  21       SELECT ARRAY_AGG(user_roles.role) INTO STRICT roles FROM user_roles WHERE user_roles.user_id = api_rate_limit.user_id;
  22
  23       IF 'moderator' = ANY(roles) THEN
  24         max_changes := moderator_changes_per_hour;
  25       ELSIF 'importer' = ANY(roles) THEN
  26         max_changes := importer_changes_per_hour;
  27       ELSE
  28         SELECT user_blocks.created_at INTO last_block FROM user_blocks WHERE user_blocks.user_id = api_rate_limit.user_id ORDER BY user_blocks.created_at DESC LIMIT 1;
  29
  30         IF FOUND THEN
  31           SELECT changesets.created_at INTO first_change FROM changesets WHERE changesets.user_id = api_rate_limit.user_id AND changesets.created_at > last_block ORDER BY changesets.created_at LIMIT 1;
  32         ELSE
  33           SELECT changesets.created_at INTO first_change FROM changesets WHERE changesets.user_id = api_rate_limit.user_id ORDER BY changesets.created_at LIMIT 1;
  34         END IF;
  35
  36         IF NOT FOUND THEN
  37           first_change := CURRENT_TIMESTAMP AT TIME ZONE 'UTC';
  38         END IF;
  39
  40         SELECT COUNT(*) INTO STRICT active_reports
  41         FROM issues INNER JOIN reports ON reports.issue_id = issues.id
  42         WHERE issues.reported_user_id = api_rate_limit.user_id AND issues.status = 'open' AND reports.updated_at >= COALESCE(issues.resolved_at, '1970-01-01');
  43
  44         time_since_first_change := EXTRACT(EPOCH FROM CURRENT_TIMESTAMP AT TIME ZONE 'UTC' - first_change);
  45
  46         max_changes := max_changes_per_hour * POWER(time_since_first_change, 2) / POWER(days_to_max_changes * 24 * 60 * 60, 2);
  47         max_changes := GREATEST(initial_changes_per_hour, LEAST(max_changes_per_hour, FLOOR(max_changes)));
  48         max_changes := max_changes / POWER(2, active_reports);
  49         max_changes := GREATEST(min_changes_per_hour, LEAST(max_changes_per_hour, max_changes));
  50       END IF;
  51
  52       SELECT COALESCE(SUM(changesets.num_changes), 0) INTO STRICT recent_changes FROM changesets WHERE changesets.user_id = api_rate_limit.user_id AND changesets.created_at >= CURRENT_TIMESTAMP AT TIME ZONE 'UTC' - '1 hour'::interval;
  53
  54       RETURN max_changes - recent_changes;
  55     END;
  56     $$ LANGUAGE plpgsql STABLE;
  57   ).freeze
  58 end