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|
{-# LANGUAGE CPP #-}
-----------------------------------------------------------------------------
-- |
-- Module : Network.HTTP.Proxy
-- Copyright : See LICENSE file
-- License : BSD
--
-- Maintainer : Ganesh Sittampalam <ganesh@earth.li>
-- Stability : experimental
-- Portability : non-portable (not tested)
--
-- Handling proxy server settings and their resolution.
--
-----------------------------------------------------------------------------
module Network.HTTP.Proxy
( Proxy(..)
, noProxy -- :: Proxy
, fetchProxy -- :: Bool -> IO Proxy
, parseProxy -- :: String -> Maybe Proxy
) where
{-
#if !defined(WIN32) && defined(mingw32_HOST_OS)
#define WIN32 1
#endif
-}
import Control.Monad ( when, mplus, join, liftM2)
#if defined(WIN32)
import Network.HTTP.Base ( catchIO )
#endif
import Network.HTTP.Utils ( dropWhileTail, chopAtDelim )
import Network.HTTP.Auth
import Network.URI
( URI(..), URIAuth(..), parseAbsoluteURI, unEscapeString )
import System.IO ( hPutStrLn, stderr )
import System.Environment
{-
#if !defined(WIN32) && defined(mingw32_HOST_OS)
#define WIN32 1
#endif
-}
#if defined(WIN32)
import System.Win32.Types ( DWORD, HKEY )
import System.Win32.Registry( hKEY_CURRENT_USER, regOpenKey, regCloseKey, regQueryValue, regQueryValueEx )
import Control.Exception ( bracket )
import Foreign ( toBool, Storable(peek, sizeOf), castPtr, alloca )
#endif
-- | HTTP proxies (or not) are represented via 'Proxy', specifying if a
-- proxy should be used for the request (see 'Network.Browser.setProxy')
data Proxy
= NoProxy -- ^ Don't use a proxy.
| Proxy String
(Maybe Authority) -- ^ Use the proxy given. Should be of the
-- form "http:\/\/host:port", "host", "host:port", or "http:\/\/host".
-- Additionally, an optional 'Authority' for authentication with the proxy.
noProxy :: Proxy
noProxy = NoProxy
-- | @envProxyString@ locates proxy server settings by looking
-- up env variable @HTTP_PROXY@ (or its lower-case equivalent.)
-- If no mapping found, returns @Nothing@.
envProxyString :: IO (Maybe String)
envProxyString = do
env <- getEnvironment
return (lookup "http_proxy" env `mplus` lookup "HTTP_PROXY" env)
-- | @proxyString@ tries to locate the user's proxy server setting.
-- Consults environment variable, and in case of Windows, by querying
-- the Registry (cf. @registryProxyString@.)
proxyString :: IO (Maybe String)
proxyString = liftM2 mplus envProxyString registryProxyString
registryProxyString :: IO (Maybe String)
#if !defined(WIN32)
registryProxyString = return Nothing
#else
registryProxyLoc :: (HKEY,String)
registryProxyLoc = (hive, path)
where
-- some sources say proxy settings should be at
-- HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows
-- \CurrentVersion\Internet Settings\ProxyServer
-- but if the user sets them with IE connection panel they seem to
-- end up in the following place:
hive = hKEY_CURRENT_USER
path = "Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings"
-- read proxy settings from the windows registry; this is just a best
-- effort and may not work on all setups.
registryProxyString = catchIO
(bracket (uncurry regOpenKey registryProxyLoc) regCloseKey $ \hkey -> do
enable <- fmap toBool $ regQueryValueDWORD hkey "ProxyEnable"
if enable
then fmap Just $ regQueryValue hkey (Just "ProxyServer")
else return Nothing)
(\_ -> return Nothing)
#endif
-- | @fetchProxy flg@ gets the local proxy settings and parse the string
-- into a @Proxy@ value. If you want to be informed of ill-formed proxy
-- configuration strings, supply @True@ for @flg@.
-- Proxy settings are sourced from the @HTTP_PROXY@ environment variable,
-- and in the case of Windows platforms, by consulting IE/WinInet's proxy
-- setting in the Registry.
fetchProxy :: Bool -> IO Proxy
fetchProxy warnIfIllformed = do
mstr <- proxyString
case mstr of
Nothing -> return NoProxy
Just str -> case parseProxy str of
Just p -> return p
Nothing -> do
when warnIfIllformed $ System.IO.hPutStrLn System.IO.stderr $ unlines
[ "invalid http proxy uri: " ++ show str
, "proxy uri must be http with a hostname"
, "ignoring http proxy, trying a direct connection"
]
return NoProxy
-- | @parseProxy str@ translates a proxy server string into a @Proxy@ value;
-- returns @Nothing@ if not well-formed.
parseProxy :: String -> Maybe Proxy
parseProxy str = join
. fmap uri2proxy
$ parseHttpURI str
`mplus` parseHttpURI ("http://" ++ str)
where
parseHttpURI str' =
case parseAbsoluteURI str' of
Just uri@URI{uriAuthority = Just{}} -> Just (fixUserInfo uri)
_ -> Nothing
-- Note: we need to be able to parse non-URIs like @\"wwwcache.example.com:80\"@
-- which lack the @\"http://\"@ URI scheme. The problem is that
-- @\"wwwcache.example.com:80\"@ is in fact a valid URI but with scheme
-- @\"wwwcache.example.com:\"@, no authority part and a path of @\"80\"@.
--
-- So our strategy is to try parsing as normal uri first and if it lacks the
-- 'uriAuthority' then we try parsing again with a @\"http://\"@ prefix.
--
-- | tidy up user portion, don't want the trailing "\@".
fixUserInfo :: URI -> URI
fixUserInfo uri = uri{ uriAuthority = f `fmap` uriAuthority uri }
where
f a@URIAuth{uriUserInfo=s} = a{uriUserInfo=dropWhileTail (=='@') s}
--
uri2proxy :: URI -> Maybe Proxy
uri2proxy uri@URI{ uriScheme = "http:"
, uriAuthority = Just (URIAuth auth' hst prt)
} =
Just (Proxy (hst ++ prt) auth)
where
auth =
case auth' of
[] -> Nothing
as -> Just (AuthBasic "" (unEscapeString usr) (unEscapeString pwd) uri)
where
(usr,pwd) = chopAtDelim ':' as
uri2proxy _ = Nothing
-- utilities
#if defined(WIN32)
regQueryValueDWORD :: HKEY -> String -> IO DWORD
regQueryValueDWORD hkey name = alloca $ \ptr -> do
-- TODO: this throws away the key type returned by regQueryValueEx
-- we should check it's what we expect instead
_ <- regQueryValueEx hkey name (castPtr ptr) (sizeOf (undefined :: DWORD))
peek ptr
#endif
|
