mirror of
https://github.com/discourse/discourse.git
synced 2024-11-24 21:50:24 +08:00
77 lines
1.5 KiB
Ruby
77 lines
1.5 KiB
Ruby
require_dependency 'rate_limiter/limit_exceeded'
|
|
require_dependency 'rate_limiter/on_create_record'
|
|
|
|
# A redis backed rate limiter.
|
|
class RateLimiter
|
|
|
|
def self.disable
|
|
@disabled = true
|
|
end
|
|
|
|
def self.enable
|
|
@disabled = false
|
|
end
|
|
|
|
# We don't observe rate limits in test mode
|
|
def self.disabled?
|
|
@disabled || Rails.env.test?
|
|
end
|
|
|
|
def initialize(user, key, max, secs)
|
|
@user = user
|
|
@key = "l-rate-limit:#{@user.id}:#{key}"
|
|
@max = max
|
|
@secs = secs
|
|
end
|
|
|
|
def clear!
|
|
$redis.del(@key)
|
|
end
|
|
|
|
def can_perform?
|
|
rate_unlimited? || is_under_limit?
|
|
end
|
|
|
|
def performed!
|
|
return if rate_unlimited?
|
|
|
|
if is_under_limit?
|
|
# simple ring buffer.
|
|
$redis.lpush(@key, Time.now.to_i)
|
|
$redis.ltrim(@key, 0, @max - 1)
|
|
|
|
# let's ensure we expire this key at some point, otherwise we have leaks
|
|
$redis.expire(@key, @secs * 2)
|
|
else
|
|
raise LimitExceeded.new(seconds_to_wait)
|
|
end
|
|
end
|
|
|
|
def rollback!
|
|
return if RateLimiter.disabled?
|
|
$redis.lpop(@key)
|
|
end
|
|
|
|
private
|
|
|
|
def seconds_to_wait
|
|
@secs - age_of_oldest
|
|
end
|
|
|
|
def age_of_oldest
|
|
# age of oldest event in buffer, in seconds
|
|
Time.now.to_i - $redis.lrange(@key, -1, -1).first.to_i
|
|
end
|
|
|
|
def is_under_limit?
|
|
# number of events in buffer less than max allowed? OR
|
|
($redis.llen(@key) < @max) ||
|
|
# age bigger than silding window size?
|
|
(age_of_oldest > @secs)
|
|
end
|
|
|
|
def rate_unlimited?
|
|
!!(RateLimiter.disabled? || @user.staff?)
|
|
end
|
|
end
|