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FileServe.hs
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FileServe.hs
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{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ScopedTypeVariables #-}
-- | Contains web handlers to serve files from a directory.
module Snap.Util.FileServe
(
getSafePath
, fileServe
, fileServe'
, fileServeSingle
, fileServeSingle'
, defaultMimeTypes
, MimeMap
) where
------------------------------------------------------------------------------
import Control.Applicative
import Control.Monad
import Control.Monad.Trans
import Data.Attoparsec.Char8 hiding (Done)
import qualified Data.ByteString.Char8 as S
import qualified Data.ByteString.Lazy.Char8 as L
import Data.ByteString.Char8 (ByteString)
import Data.Int
import Data.Map (Map)
import qualified Data.Map as Map
import Data.Maybe (fromMaybe, isNothing)
import Prelude hiding (show, Show)
import qualified Prelude
import System.Directory
import System.FilePath
import System.PosixCompat.Files
import Text.Show.ByteString hiding (runPut)
------------------------------------------------------------------------------
import Snap.Internal.Debug
import Snap.Internal.Parsing
import Snap.Iteratee hiding (drop)
import Snap.Types
------------------------------------------------------------------------------
-- | A type alias for MIME type
type MimeMap = Map FilePath ByteString
------------------------------------------------------------------------------
-- | The default set of mime type mappings we use when serving files. Its
-- value:
--
-- > Map.fromList [
-- > ( ".asc" , "text/plain" ),
-- > ( ".asf" , "video/x-ms-asf" ),
-- > ( ".asx" , "video/x-ms-asf" ),
-- > ( ".avi" , "video/x-msvideo" ),
-- > ( ".bz2" , "application/x-bzip" ),
-- > ( ".c" , "text/plain" ),
-- > ( ".class" , "application/octet-stream" ),
-- > ( ".conf" , "text/plain" ),
-- > ( ".cpp" , "text/plain" ),
-- > ( ".css" , "text/css" ),
-- > ( ".cxx" , "text/plain" ),
-- > ( ".dtd" , "text/xml" ),
-- > ( ".dvi" , "application/x-dvi" ),
-- > ( ".gif" , "image/gif" ),
-- > ( ".gz" , "application/x-gzip" ),
-- > ( ".hs" , "text/plain" ),
-- > ( ".htm" , "text/html" ),
-- > ( ".html" , "text/html" ),
-- > ( ".jar" , "application/x-java-archive" ),
-- > ( ".jpeg" , "image/jpeg" ),
-- > ( ".jpg" , "image/jpeg" ),
-- > ( ".js" , "text/javascript" ),
-- > ( ".log" , "text/plain" ),
-- > ( ".m3u" , "audio/x-mpegurl" ),
-- > ( ".mov" , "video/quicktime" ),
-- > ( ".mp3" , "audio/mpeg" ),
-- > ( ".mpeg" , "video/mpeg" ),
-- > ( ".mpg" , "video/mpeg" ),
-- > ( ".ogg" , "application/ogg" ),
-- > ( ".pac" , "application/x-ns-proxy-autoconfig" ),
-- > ( ".pdf" , "application/pdf" ),
-- > ( ".png" , "image/png" ),
-- > ( ".ps" , "application/postscript" ),
-- > ( ".qt" , "video/quicktime" ),
-- > ( ".sig" , "application/pgp-signature" ),
-- > ( ".spl" , "application/futuresplash" ),
-- > ( ".swf" , "application/x-shockwave-flash" ),
-- > ( ".tar" , "application/x-tar" ),
-- > ( ".tar.bz2" , "application/x-bzip-compressed-tar" ),
-- > ( ".tar.gz" , "application/x-tgz" ),
-- > ( ".tbz" , "application/x-bzip-compressed-tar" ),
-- > ( ".text" , "text/plain" ),
-- > ( ".tgz" , "application/x-tgz" ),
-- > ( ".torrent" , "application/x-bittorrent" ),
-- > ( ".txt" , "text/plain" ),
-- > ( ".wav" , "audio/x-wav" ),
-- > ( ".wax" , "audio/x-ms-wax" ),
-- > ( ".wma" , "audio/x-ms-wma" ),
-- > ( ".wmv" , "video/x-ms-wmv" ),
-- > ( ".xbm" , "image/x-xbitmap" ),
-- > ( ".xml" , "text/xml" ),
-- > ( ".xpm" , "image/x-xpixmap" ),
-- > ( ".xwd" , "image/x-xwindowdump" ),
-- > ( ".zip" , "application/zip" ) ]
--
defaultMimeTypes :: MimeMap
defaultMimeTypes = Map.fromList [
( ".asc" , "text/plain" ),
( ".asf" , "video/x-ms-asf" ),
( ".asx" , "video/x-ms-asf" ),
( ".avi" , "video/x-msvideo" ),
( ".bz2" , "application/x-bzip" ),
( ".c" , "text/plain" ),
( ".class" , "application/octet-stream" ),
( ".conf" , "text/plain" ),
( ".cpp" , "text/plain" ),
( ".css" , "text/css" ),
( ".cxx" , "text/plain" ),
( ".dtd" , "text/xml" ),
( ".dvi" , "application/x-dvi" ),
( ".gif" , "image/gif" ),
( ".gz" , "application/x-gzip" ),
( ".hs" , "text/plain" ),
( ".htm" , "text/html" ),
( ".html" , "text/html" ),
( ".jar" , "application/x-java-archive" ),
( ".jpeg" , "image/jpeg" ),
( ".jpg" , "image/jpeg" ),
( ".js" , "text/javascript" ),
( ".log" , "text/plain" ),
( ".m3u" , "audio/x-mpegurl" ),
( ".mov" , "video/quicktime" ),
( ".mp3" , "audio/mpeg" ),
( ".mpeg" , "video/mpeg" ),
( ".mpg" , "video/mpeg" ),
( ".ogg" , "application/ogg" ),
( ".pac" , "application/x-ns-proxy-autoconfig" ),
( ".pdf" , "application/pdf" ),
( ".png" , "image/png" ),
( ".ps" , "application/postscript" ),
( ".qt" , "video/quicktime" ),
( ".sig" , "application/pgp-signature" ),
( ".spl" , "application/futuresplash" ),
( ".swf" , "application/x-shockwave-flash" ),
( ".tar" , "application/x-tar" ),
( ".tar.bz2" , "application/x-bzip-compressed-tar" ),
( ".tar.gz" , "application/x-tgz" ),
( ".tbz" , "application/x-bzip-compressed-tar" ),
( ".text" , "text/plain" ),
( ".tgz" , "application/x-tgz" ),
( ".torrent" , "application/x-bittorrent" ),
( ".ttf" , "application/x-font-truetype" ),
( ".txt" , "text/plain" ),
( ".wav" , "audio/x-wav" ),
( ".wax" , "audio/x-ms-wax" ),
( ".wma" , "audio/x-ms-wma" ),
( ".wmv" , "video/x-ms-wmv" ),
( ".xbm" , "image/x-xbitmap" ),
( ".xml" , "text/xml" ),
( ".xpm" , "image/x-xpixmap" ),
( ".xwd" , "image/x-xwindowdump" ),
( ".zip" , "application/zip" ) ]
------------------------------------------------------------------------------
-- | Gets a path from the 'Request' using 'rqPathInfo' and makes sure it is
-- safe to use for opening files. A path is safe if it is a relative path
-- and has no ".." elements to escape the intended directory structure.
getSafePath :: MonadSnap m => m FilePath
getSafePath = do
req <- getRequest
let mp = urlDecode $ rqPathInfo req
p <- maybe pass (return . S.unpack) mp
-- relative paths only!
when (not $ isRelative p) pass
-- check that we don't have any sneaky .. paths
let dirs = splitDirectories p
when (elem ".." dirs) pass
return $ joinPath dirs
------------------------------------------------------------------------------
-- | Serves files out of the given directory. The relative path given in
-- 'rqPathInfo' is searched for the given file, and the file is served with
-- the appropriate mime type if it is found. Absolute paths and \"@..@\" are
-- prohibited to prevent files from being served from outside the sandbox.
--
-- Uses 'defaultMimeTypes' to determine the @Content-Type@ based on the file's
-- extension.
fileServe :: MonadSnap m
=> FilePath -- ^ root directory
-> m ()
fileServe = fileServe' defaultMimeTypes
{-# INLINE fileServe #-}
------------------------------------------------------------------------------
-- | Same as 'fileServe', with control over the MIME mapping used.
fileServe' :: MonadSnap m
=> MimeMap -- ^ MIME type mapping
-> FilePath -- ^ root directory
-> m ()
fileServe' mm root = do
sp <- getSafePath
let fp = root </> sp
-- check that the file exists
liftIO (doesFileExist fp) >>= flip unless pass
let fn = takeFileName fp
let mime = fileType mm fn
fileServeSingle' mime fp
{-# INLINE fileServe' #-}
------------------------------------------------------------------------------
-- | Serves a single file specified by a full or relative path. The
-- path restrictions on fileServe don't apply to this function since
-- the path is not being supplied by the user.
fileServeSingle :: MonadSnap m
=> FilePath -- ^ path to file
-> m ()
fileServeSingle fp =
fileServeSingle' (fileType defaultMimeTypes (takeFileName fp)) fp
{-# INLINE fileServeSingle #-}
------------------------------------------------------------------------------
-- | Same as 'fileServeSingle', with control over the MIME mapping used.
fileServeSingle' :: MonadSnap m
=> ByteString -- ^ MIME type mapping
-> FilePath -- ^ path to file
-> m ()
fileServeSingle' mime fp = do
reqOrig <- getRequest
-- If-Range header must be ignored if there is no Range: header in the
-- request (RFC 2616 section 14.27)
let req = if isNothing $ getHeader "range" reqOrig
then deleteHeader "if-range" reqOrig
else reqOrig
-- check "If-Modified-Since" and "If-Range" headers
let mbH = getHeader "if-modified-since" req
mbIfModified <- liftIO $ case mbH of
Nothing -> return Nothing
(Just s) -> liftM Just $ parseHttpTime s
-- If-Range header could contain an entity, but then parseHttpTime will
-- fail and return 0 which means a 200 response will be generated anyways
mbIfRange <- liftIO $ case getHeader "if-range" req of
Nothing -> return Nothing
(Just s) -> liftM Just $ parseHttpTime s
dbg $ "mbIfModified: " ++ Prelude.show mbIfModified
dbg $ "mbIfRange: " ++ Prelude.show mbIfRange
-- check modification time and bug out early if the file is not modified.
--
-- TODO: a stat cache would be nice here, but it'd need the date thread
-- stuff from snap-server to be folded into snap-core
filestat <- liftIO $ getFileStatus fp
let mt = modificationTime filestat
maybe (return $! ()) (\lt -> when (mt <= lt) notModified) mbIfModified
let sz = fromIntegral $ fileSize filestat
lm <- liftIO $ formatHttpTime mt
-- ok, at this point we know the last-modified time and the
-- content-type. set those.
modifyResponse $ setHeader "Last-Modified" lm
. setHeader "Accept-Ranges" "bytes"
. setContentType mime
-- now check: is this a range request? If there is an 'If-Range' header
-- with an old modification time we skip this check and send a 200
-- response
let skipRangeCheck = maybe (False)
(\lt -> mt > lt)
mbIfRange
-- checkRangeReq checks for a Range: header in the request and sends a
-- partial response if it matches.
wasRange <- if skipRangeCheck
then return False
else liftSnap $ checkRangeReq req fp sz
dbg $ "was this a range request? " ++ Prelude.show wasRange
-- if we didn't have a range request, we just do normal sendfile
unless wasRange $ do
modifyResponse $ setResponseCode 200
. setContentLength sz
liftSnap $ sendFile fp
where
--------------------------------------------------------------------------
notModified = finishWith $
setResponseCode 304 emptyResponse
------------------------------------------------------------------------------
fileType :: MimeMap -> FilePath -> ByteString
fileType mm f =
if null ext
then defaultMimeType
else fromMaybe (fileType mm (drop 1 ext))
mbe
where
ext = takeExtensions f
mbe = Map.lookup ext mm
------------------------------------------------------------------------------
defaultMimeType :: ByteString
defaultMimeType = "application/octet-stream"
------------------------------------------------------------------------------
data RangeReq = RangeReq { _rangeFirst :: !Int64
, _rangeLast :: !(Maybe Int64)
}
| SuffixRangeReq { _suffixLength :: !Int64 }
deriving (Eq, Prelude.Show)
------------------------------------------------------------------------------
rangeParser :: Parser RangeReq
rangeParser = string "bytes=" *>
(byteRangeSpec <|> suffixByteRangeSpec) <*
endOfInput
where
byteRangeSpec = do
start <- parseNum
char '-'
end <- option Nothing $ liftM Just parseNum
return $ RangeReq start end
suffixByteRangeSpec = liftM SuffixRangeReq $ char '-' *> parseNum
------------------------------------------------------------------------------
checkRangeReq :: (MonadSnap m) => Request -> FilePath -> Int64 -> m Bool
checkRangeReq req fp sz = do
-- TODO/FIXME: multiple ranges
dbg $ "checkRangeReq, fp=" ++ fp ++ ", sz=" ++ Prelude.show sz
maybe (return False)
(\s -> either (const $ return False)
withRange
(fullyParse s rangeParser))
(getHeader "range" req)
where
withRange rng@(RangeReq start mend) = do
dbg $ "withRange: got Range request: " ++ Prelude.show rng
let end = fromMaybe (sz-1) mend
dbg $ "withRange: start=" ++ Prelude.show start
++ ", end=" ++ Prelude.show end
if start < 0 || end < start || start >= sz || end >= sz
then send416
else send206 start end
withRange rng@(SuffixRangeReq nbytes) = do
dbg $ "withRange: got Range request: " ++ Prelude.show rng
let end = sz-1
let start = sz - nbytes
dbg $ "withRange: start=" ++ Prelude.show start
++ ", end=" ++ Prelude.show end
if start < 0 || end < start || start >= sz || end >= sz
then send416
else send206 start end
-- note: start and end INCLUSIVE here
send206 start end = do
dbg "inside send206"
let len = end-start+1
let crng = S.concat $
L.toChunks $
L.concat [ "bytes "
, show start
, "-"
, show end
, "/"
, show sz ]
modifyResponse $ setResponseCode 206
. setHeader "Content-Range" crng
. setContentLength len
dbg $ "send206: sending range (" ++ Prelude.show start
++ "," ++ Prelude.show (end+1) ++ ") to sendFilePartial"
-- end here was inclusive, sendFilePartial is exclusive
sendFilePartial fp (start,end+1)
return True
send416 = do
dbg "inside send416"
-- if there's an "If-Range" header in the request, then we just send
-- back 200
if getHeader "If-Range" req /= Nothing
then return False
else do
let crng = S.concat $
L.toChunks $
L.concat ["bytes */", show sz]
modifyResponse $ setResponseCode 416
. setHeader "Content-Range" crng
. setContentLength 0
. deleteHeader "Content-Type"
. deleteHeader "Content-Encoding"
. deleteHeader "Transfer-Encoding"
. setResponseBody (enumBS "")
return True
------------------------------------------------------------------------------
dbg :: (MonadIO m) => String -> m ()
dbg s = debug $ "FileServe:" ++ s