This is a WAI middleware for blocking incoming requests by IP range.

See Haddock for documentation, including the YAML configuration format.

To use this with the Yesod scaffold, modify the makeApplication function in Application.hs like so:

makeApplication :: App -> IO Application
makeApplication foundation = do
    logWare <- makeLogWare foundation
    -- Create the WAI application and apply middlewares
    appPlain <- toWaiAppPlain foundation
    ipBlock <- ipBlockMiddlewareFromFileEnv "IP_BLOCK_CFG" basicDenyResponse
    return $ logWare $ ipBlock $ defaultMiddlewaresNoLogging appPlain

When your server launches, it'll look for an environment variable IP_BLOCK_CFG. That should have the path to a YAML formatted configuration file. The details of that format are in the Haddock.

Note: the ordering of the middleware above is important! logWare must be applied after ipBlock so that blocked requests are logged. Otherwise they will be dropped silently - this library does no logging on its own.

Don't rely on this for security. I wrote this so I could put a site up on the internet before I was ready to make it public. IP based blocking is in general a weak measure and this package in particular has undergone relatively little testing, none of it adversarial.