Network.Wai.Middleware.Throttle

Uses a Token Bucket algorithm (from the token-bucket package) to throttle WAI Requests.

Example

main = do
  let expirationSpec = TimeSpec 5 0 -- five seconds
  th <- initThrottler (defaultThrottleSettings expirationSpec) (const $ Right 1)
  let appl = throttle th $  _ f -> f $
        responseLBS ok200 [] "ok"
  Warp.run 3000 app

Documentation

data ThrottleSettings

Throttle settings for controlling token bucket algorithm and cache expiration.

Constructors

ThrottleSettings

Fields

• throttleSettingsRate :: Double

  Number of requests per throttle period allowed, defaults to 1

• throttleSettingsPeriod :: Double

  Microseconds, defaults to 1 second

• throttleSettingsBurst :: Word64

  Number of concurrent requests allowed - should be greater than rate / period, defaults to 1

• throttleSettingsCacheExpiration :: TimeSpec

  The amount of time before a stale token bucket is purged from the cache

• throttleSettingsIsThrottled :: Request -> Bool

  Whether or not a request is throttled, defaults to true

• throttleSettingsOnThrottled :: Word64 -> Response

  The response when a request is throttled - defaults to a vanilla 429

data Throttle a

A throttle for a hashable key type. Initialize using initThrottler with defaultThrottleSettings.

Constructors

Throttle

Fields

• throttleSettings :: ThrottleSettings

  The throttle settings

• throttleCache :: Cache a (CacheState TokenBucket)

  The cache, initialized in initThrottler

• throttleGetKey :: Request -> Either Response a

  The function to extract a throttle key from a Request

newtype Address

Constructors

Address SockAddr

Instances

Eq Address

Defined in Network.Wai.Middleware.Throttle.Internal

Methods

(==) :: Address -> Address -> Bool

(/=) :: Address -> Address -> Bool

Ord Address

Defined in Network.Wai.Middleware.Throttle.Internal

Methods

compare :: Address -> Address -> Ordering

(<) :: Address -> Address -> Bool

(<=) :: Address -> Address -> Bool

(>) :: Address -> Address -> Bool

(>=) :: Address -> Address -> Bool

max :: Address -> Address -> Address

min :: Address -> Address -> Address

Hashable Address

Defined in Network.Wai.Middleware.Throttle.Internal

Methods

hashWithSalt :: Int -> Address -> Int

hash :: Address -> Int

extractAddress :: Request -> Either Response Address

defaultThrottleSettings :: TimeSpec -> ThrottleSettings

Default throttle settings.

initThrottler :: ThrottleSettings -> IO (Throttle Address)

initCustomThrottler :: ThrottleSettings -> (Request -> Either Response a) -> IO (Throttle a)

Initialize a throttle using settings and a way to extract the key from the request.

throttle :: (Eq a, Hashable a) => Throttle a -> Application -> Application

Run the throttling middleware given a throttle that has been initialized.