Network.Wai.Middleware.Throttle

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

Example

main = do
  st <- initThrottler
  let payload  = "{ "api": "return data" }"
      app = throttle defaultThrottleSettings st
              $ _ f -> f (responseLBS status200 [] payload)
  Warp.run 3000 app

Documentation

Wai Request Throttling Middleware

throttle :: RequestHashable a => ThrottleSettings -> CustomWaiThrottle a -> Application -> Application

WAI Request Throttling Middleware.

Uses a Requests remoteHost function to resolve the remote IP address.

Wai Throttle middleware state.

Essentially, a TVar with a HashMap for indexing remote IP address

type WaiThrottle = CustomWaiThrottle Address

A synonym for an IP address throttle

data CustomWaiThrottle a

A throttle for a type implementing RequestHashable

initThrottler :: IO WaiThrottle

Initialize an IP address throttler

initCustomThrottler :: IO (CustomWaiThrottle a)

Initialize a "custom" throttler that implements the RequestHashable class

Throttle settings and configuration

data ThrottleSettings

Settings which control various behaviors in the middleware.

Constructors

ThrottleSettings

Fields

• isThrottled :: !(Request -> IO Bool)

  Determines whether the Request is throttled

• onThrottled :: !(Word64 -> Response)

  Function to run when the request is throttled.

  The first argument is a Word64 containing the amount of microseconds until the next retry should be attempted.

• onRequestError :: !(Text -> Response)

  Function to run when the throttler fails to extract the key.

  The first argument is a Text containing the error message.

• throttleRate :: !Integer

  Rate

• throttlePeriod :: !Integer
• throttleBurst :: !Integer

  Burst rate

defaultThrottleSettings :: ThrottleSettings

Default settings to throttle requests.

newtype Address

Constructors

Address SockAddr

Instances

Eq Address

Methods

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

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

Ord Address

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

Methods

hashWithSalt :: Int -> Address -> Int

hash :: Address -> Int

RequestHashable Address

Methods

requestToKey :: (Functor m, Monad m) => Request -> ExceptT Text m Address

class (Eq a, Ord a, Hashable a) => RequestHashable a where

A class extracting a hashable key from a Request to store in an in-memory map

Minimal complete definition

requestToKey

Methods

requestToKey :: (Functor m, Monad m) => Request -> ExceptT Text m a

Instances

RequestHashable Address

Methods

requestToKey :: (Functor m, Monad m) => Request -> ExceptT Text m Address