Safe Haskell	None
Language	Haskell2010

Network.Wai.Logger

Contents

High level functions
Creating a logger
Types
Date cacher
Utilities

Description

Apache style logger for WAI applications.

An example:

{-# LANGUAGE OverloadedStrings #-}
module Main where

import Blaze.ByteString.Builder (fromByteString)
import Control.Monad.IO.Class (liftIO)
import qualified Data.ByteString.Char8 as BS
import Network.HTTP.Types (status200)
import Network.Wai (Application, responseBuilder)
import Network.Wai.Handler.Warp (run)
import Network.Wai.Logger (withStdoutLogger, ApacheLogger)

main :: IO ()
main = withStdoutLogger $ \aplogger ->
    run 3000 $ logApp aplogger

logApp :: ApacheLogger -> Application
logApp aplogger req = do
    liftIO $ aplogger req status (Just len)
    return $ responseBuilder status hdr msg
  where
    status = status200
    hdr = [("Content-Type", "text/plain")
          ,("Content-Length", BS.pack (show len))]
    pong = "PONG"
    len = fromIntegral $ BS.length pong
    msg = toLogStr pong

Synopsis

High level functions

type ApacheLogger = Request -> Status -> Maybe Integer -> IO () Source

Apache style logger.

withStdoutLogger :: (ApacheLogger -> IO a) -> IO a Source

Executing a function which takes ApacheLogger. This ApacheLogger writes log message to stdout. Each buffer (4K bytes) is flushed every second.

Creating a logger

data ApacheLoggerActions Source

Constructors

ApacheLoggerActions

Fields

apacheLogger :: ApacheLogger
logFlusher :: IO (): Flushing log messages in the buffers. This is explicitly called from your program. Probably, one second and 10 seconds is proper to stdout and log files, respectively. See the source code of withStdoutLogger.
logRotator :: IO (): Rotating log files. This is explicitly called from your program. Probably, 10 seconds is proper.
logRemover :: IO (): Removing resources relating Apache logger.

initLogger :: IPAddrSource -> LogType -> DateCacheGetter -> IO ApacheLoggerActions Source

Creating ApacheLogger according to LogType.

Types

data IPAddrSource Source

Source from which the IP source address of the client is obtained.

Constructors

FromSocket	From the peer address of the HTTP connection.
FromHeader	From X-Real-IP: or X-Forwarded-For: in the HTTP header.
FromFallback	From the peer address if header is not found.

data LogType Source

Logger Type.

Constructors

LogNone	No logging.
LogStdout BufSize	Logging to stdout. `BufSize` is a buffer size for each capability.
LogFile FileLogSpec BufSize	Logging to a file. `BufSize` is a buffer size for each capability.
LogCallback (LogStr -> IO ()) (IO ())