---------------------------------------------------------------
-- Copyright (c) 2014, Enzo Haussecker. All rights reserved. --
---------------------------------------------------------------

{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE OverloadedStrings #-}
{-# OPTIONS -Wall              #-}

-- | A simple SMTP Client for sending Gmail.
module Network.Mail.Client.Gmail (sendGmail) where

import Control.Monad (foldM_, forM, liftM, void)
import Crypto.Random.AESCtr (makeSystem)
import Data.ByteString.Char8 (lines, unpack)
import Data.ByteString.Base64.Lazy (encode)
import Data.ByteString.Lazy.Char8 (ByteString, readFile)
import Data.ByteString.Lazy.Search (replace)
import Data.Char (isDigit, isSpace)
import Data.Default (def)
import Data.Monoid ((<>))
import Data.Text as Strict (Text, pack)
import Data.Text.Lazy as Lazy (Text, fromChunks)
import Data.Text.Lazy.Encoding (encodeUtf8)
import Network (PortID(PortNumber), connectTo)
import Network.Mail.Mime hiding (renderMail)
import Network.TLS
import Network.TLS.Extra
import Prelude hiding (any, lines, readFile)
import System.FilePath (takeExtension, takeFileName)
import System.IO hiding (readFile)
import System.Timeout (timeout)

-- | Send an email from your Gmail account using the simple
--   message transfer protocol with transport layer security.
--   Below is an example using ghci, where Alice sends an
--   Excel spreadsheet to Bob.
--
-- > >>> :set -XOverloadedStrings
-- > >>> :module Network.Mail.Mime Network.Mail.Client.Gmail
-- > >>> sendGmail "alice" "password" (Address (Just "Alice") "alice@gmail.com") [Address (Just "Bob") "bob@example.com"] [] [] "Excel Spreadsheet" "Hi Bob,\n\nThe Excel spreadsheet is attached.\n\nRegards,\n\nAlice" ["spreadsheet.xls"] Nothing
--
sendGmail
  :: Lazy.Text   -- ^ username
  -> Lazy.Text   -- ^ password
  -> Address     -- ^ from
  -> [Address]   -- ^ to
  -> [Address]   -- ^ cc
  -> [Address]   -- ^ bcc
  -> Strict.Text -- ^ subject
  -> Lazy.Text   -- ^ body
  -> [FilePath]  -- ^ attachments
  -> Maybe Int   -- ^ timeout in microseconds
  -> IO ()
sendGmail user pass from to cc bcc subject body attach lim = do
  hdl   <- connectTo "smtp.gmail.com" $ PortNumber 587
  sys   <- makeSystem
  ctx   <- contextNew hdl params sys
  _MAIL <- renderMail from to cc bcc subject body attach
  hSetBuffering hdl LineBuffering
  ----------------------------
  -- BEGIN MESSAGE EXCHANGE --
  ----------------------------
  sendSMTP  hdl "EHLO"       >> recvSMTP  hdl lim "220"
                             >> recvSMTP  hdl lim "250"
  sendSMTP  hdl "STARTTLS"   >> recvSMTP  hdl lim "220"
  handshake ctx
  sendSMTPS ctx "EHLO"       >> recvSMTPS ctx lim "250"
  sendSMTPS ctx "AUTH LOGIN" >> recvSMTPS ctx lim "334"
  sendSMTPS ctx _USERNAME    >> recvSMTPS ctx lim "334"
  sendSMTPS ctx _PASSWORD    >> recvSMTPS ctx lim "235"
  sendSMTPS ctx _FROM        >> recvSMTPS ctx lim "250"
  sendSMTPS ctx _TO          >> recvSMTPS ctx lim "250"
  sendSMTPS ctx "DATA"       >> recvSMTPS ctx lim "354"
  sendSMTPS ctx _MAIL        >> recvSMTPS ctx lim "250"
  sendSMTPS ctx "QUIT"       >> recvSMTPS ctx lim "221"
  ----------------------------
  --- END MESSAGE EXCHANGE ---
  ----------------------------
  bye ctx
  contextClose ctx
  hClose hdl
  where _USERNAME  = encode $ encodeUtf8 user
        _PASSWORD  = encode $ encodeUtf8 pass
        _FROM      = "MAIL FROM: " <> angleBracket [from]
        _TO        = "RCPT TO: "   <> angleBracket (to ++ cc ++ bcc)

-- | Display the first email address in the given list using angle bracket formatting.
angleBracket :: [Address] -> ByteString
angleBracket = \ case [] -> ""; (Address _ email:_) -> "<" <> encodeUtf8 (fromChunks [email]) <> ">"

-- | Render an email using the RFC 2822 message format.
renderMail
  :: Address     -- ^ from
  -> [Address]   -- ^ to
  -> [Address]   -- ^ cc
  -> [Address]   -- ^ bcc
  -> Strict.Text -- ^ subject
  -> Lazy.Text   -- ^ body
  -> [FilePath]  -- ^ attachments
  -> IO ByteString
renderMail from to cc bcc subject body attach = do
  parts <- forM attach $ \ path -> do
    content <- readFile path
    let mime = getMime $ takeExtension path
        file = Just . pack $ takeFileName path
    return $! [Part mime Base64 file [] content]
  let plain = [Part "text/plain; charset=utf-8" QuotedPrintableText Nothing [] $ encodeUtf8 body]
  mail <- renderMail' . Mail from to cc bcc headers $ plain : parts
  return $! replace "\n." ("\n.."::ByteString) mail <> "\r\n.\r\n"
  where headers = [("Subject",subject)]

-- | Send an unencrypted message using the simple message transfer protocol.
sendSMTP
  :: Handle -- ^ connection
  -> String -- ^ message
  -> IO ()
sendSMTP = hPutStrLn

-- | Receive an unencrypted message using the simple message transfer protocol.
recvSMTP
  :: Handle    -- ^ connection
  -> Maybe Int -- ^ timeout in microseconds
  -> String    -- ^ expected reply code
  -> IO ()
recvSMTP hdl lim code = void $
  step [] where
  step accum = do
    mval <- maybe (liftM Just) timeout lim $ hGetLine hdl
    case mval of
      Nothing    -> fail "recvSMTP: connection timeout"
      Just reply -> match code reply step accum

-- | Send an encrypted message using the simple message transfer protocol.
sendSMTPS
  :: Context    -- ^ connection
  -> ByteString -- ^ message
  -> IO ()
sendSMTPS ctx msg = sendData ctx $ msg <> "\r\n"

-- | Receive an encrypted message using the simple message transfer protocol.
recvSMTPS
  :: Context   -- ^ connection
  -> Maybe Int -- ^ timeout in microseconds
  -> String    -- ^ expected reply code
  -> IO ()
recvSMTPS ctx lim code = do
  mval <- maybe (liftM Just) timeout lim $ recvData ctx
  case mval of
    Nothing      -> fail "recvSMTPS: connection timeout"
    Just replies -> foldM_ step [] $ lines replies
    -- NOTE: Here we assume that the whole response arrives in
    -- one TLS packet. That assumption is not necessarily true.
    where step accum reply = match code (unpack reply) return accum

-- | A convenient type synonym.
type Continuation = [String] -> IO [String]

-- | Match reply codes and perform continuation, termination, and failure case analysis.
match
  :: String       -- ^ expected reply code
  -> String       -- ^ reply
  -> Continuation -- ^ continuation
  -> [String]     -- ^ accumulator
  -> IO [String]
match code reply continuation accum =
  if not (null suffix) && head suffix == '-'
  then continuation $ drop 1 suffix:accum
  else if prefix == code && "" /= code
       then return []
       else mismatch code prefix $ suffix:accum
       where (prefix, suffix) = break (not . isDigit) reply

-- | Raise an exception for mismatched reply codes.
mismatch
  :: String   -- ^ expected reply code
  -> String   -- ^ received reply code
  -> [String] -- ^ messages
  -> IO [String]
mismatch code other replies = fail $
  if null code
  then "mismatch: missing expected reply code."
  else "mismatch: expected reply code " ++ code ++
   (if null other
    then ", but no reply code was received"
    else ", but received reply code " ++ other) ++
    case filter (not . null) $ map strip replies of
      []     -> "."
      (r:rs) -> ": " ++ foldl step (strip r) rs ++ "."
      where strip = dropWhile isSpace . filter (/='\r')
            step accum = flip (++) $ "; " ++ accum

-- | TLS client parameters.
params :: ClientParams 
params = (defaultParamsClient "smtp.gmail.com" "587")
  { clientSupported  = def { supportedCiphers      = ciphersuite_all }
  , clientShared     = def { sharedValidationCache = noValidate      }
  } where noValidate = ValidationCache (\_ _ _ -> return ValidationCachePass)
                                       (\_ _ _ -> return ())

-- | Get the mime type for the given file extension.
getMime :: String -> Strict.Text
getMime = \ case
  ".3dm"       -> "x-world/x-3dmf"
  ".3dmf"      -> "x-world/x-3dmf"
  ".a"         -> "application/octet-stream"
  ".aab"       -> "application/x-authorware-bin"
  ".aam"       -> "application/x-authorware-map"
  ".aas"       -> "application/x-authorware-seg"
  ".abc"       -> "text/vnd.abc"
  ".acgi"      -> "text/html"
  ".afl"       -> "video/animaflex"
  ".ai"        -> "application/postscript"
  ".aif"       -> "audio/aiff"
  ".aifc"      -> "audio/aiff"
  ".aiff"      -> "audio/aiff"
  ".aim"       -> "application/x-aim"
  ".aip"       -> "text/x-audiosoft-intra"
  ".ani"       -> "application/x-navi-animation"
  ".aos"       -> "application/x-nokia-9000-communicator-add-on-software"
  ".aps"       -> "application/mime"
  ".arc"       -> "application/octet-stream"
  ".arj"       -> "application/arj"
  ".art"       -> "image/x-jg"
  ".asf"       -> "video/x-ms-asf"
  ".asm"       -> "text/x-asm"
  ".asp"       -> "text/asp"
  ".asx"       -> "application/x-mplayer2"
  ".au"        -> "audio/basic"
  ".avi"       -> "application/x-troff-msvideo"
  ".avs"       -> "video/avs-video"
  ".bcpio"     -> "application/x-bcpio"
  ".bin"       -> "application/mac-binary"
  ".bm"        -> "image/bmp"
  ".bmp"       -> "image/bmp"
  ".boo"       -> "application/book"
  ".book"      -> "application/book"
  ".boz"       -> "application/x-bzip2"
  ".bsh"       -> "application/x-bsh"
  ".bz"        -> "application/x-bzip"
  ".bz2"       -> "application/x-bzip2"
  ".c"         -> "text/plain"
  ".c++"       -> "text/plain"
  ".cat"       -> "application/vnd.ms-pki.seccat"
  ".cc"        -> "text/plain"
  ".ccad"      -> "application/clariscad"
  ".cco"       -> "application/x-cocoa"
  ".cdf"       -> "application/cdf"
  ".cer"       -> "application/pkix-cert"
  ".cha"       -> "application/x-chat"
  ".chat"      -> "application/x-chat"
  ".class"     -> "application/java"
  ".com"       -> "application/octet-stream"
  ".conf"      -> "text/plain"
  ".cpio"      -> "application/x-cpio"
  ".cpp"       -> "text/x-c"
  ".cpt"       -> "application/mac-compactpro"
  ".crl"       -> "application/pkcs-crl"
  ".crt"       -> "application/pkix-cert"
  ".csh"       -> "application/x-csh"
  ".css"       -> "application/x-pointplus"
  ".cxx"       -> "text/plain"
  ".dcr"       -> "application/x-director"
  ".deepv"     -> "application/x-deepv"
  ".def"       -> "text/plain"
  ".der"       -> "application/x-x509-ca-cert"
  ".dif"       -> "video/x-dv"
  ".dir"       -> "application/x-director"
  ".dl"        -> "video/dl"
  ".doc"       -> "application/msword"
  ".dot"       -> "application/msword"
  ".dp"        -> "application/commonground"
  ".drw"       -> "application/drafting"
  ".dump"      -> "application/octet-stream"
  ".dv"        -> "video/x-dv"
  ".dvi"       -> "application/x-dvi"
  ".dwf"       -> "drawing/x-dwf (old)"
  ".dwg"       -> "application/acad"
  ".dxf"       -> "application/dxf"
  ".dxr"       -> "application/x-director"
  ".el"        -> "text/x-script.elisp"
  ".elc"       -> "application/x-bytecode.elisp (compiled elisp)"
  ".env"       -> "application/x-envoy"
  ".eps"       -> "application/postscript"
  ".es"        -> "application/x-esrehber"
  ".etx"       -> "text/x-setext"
  ".evy"       -> "application/envoy"
  ".exe"       -> "application/octet-stream"
  ".f"         -> "text/plain"
  ".f77"       -> "text/x-fortran"
  ".f90"       -> "text/plain"
  ".fdf"       -> "application/vnd.fdf"
  ".fif"       -> "application/fractals"
  ".fli"       -> "video/fli"
  ".flo"       -> "image/florian"
  ".flx"       -> "text/vnd.fmi.flexstor"
  ".fmf"       -> "video/x-atomic3d-feature"
  ".for"       -> "text/plain"
  ".fpx"       -> "image/vnd.fpx"
  ".frl"       -> "application/freeloader"
  ".funk"      -> "audio/make"
  ".g"         -> "text/plain"
  ".g3"        -> "image/g3fax"
  ".gif"       -> "image/gif"
  ".gl"        -> "video/gl"
  ".gsd"       -> "audio/x-gsm"
  ".gsm"       -> "audio/x-gsm"
  ".gsp"       -> "application/x-gsp"
  ".gss"       -> "application/x-gss"
  ".gtar"      -> "application/x-gtar"
  ".gz"        -> "application/x-compressed"
  ".gzip"      -> "application/x-gzip"
  ".h"         -> "text/plain"
  ".hdf"       -> "application/x-hdf"
  ".help"      -> "application/x-helpfile"
  ".hgl"       -> "application/vnd.hp-hpgl"
  ".hh"        -> "text/plain"
  ".hlb"       -> "text/x-script"
  ".hlp"       -> "application/hlp"
  ".hpg"       -> "application/vnd.hp-hpgl"
  ".hpgl"      -> "application/vnd.hp-hpgl"
  ".hqx"       -> "application/binhex"
  ".hs"        -> "text/x-haskell"
  ".hta"       -> "application/hta"
  ".htc"       -> "text/x-component"
  ".htm"       -> "text/html"
  ".html"      -> "text/html"
  ".htmls"     -> "text/html"
  ".htt"       -> "text/webviewhtml"
  ".htx"       -> "text/html"
  ".ice"       -> "x-conference/x-cooltalk"
  ".ico"       -> "image/x-icon"
  ".idc"       -> "text/plain"
  ".ief"       -> "image/ief"
  ".iefs"      -> "image/ief"
  ".iges"      -> "application/iges"
  ".igs"       -> "application/iges"
  ".ima"       -> "application/x-ima"
  ".imap"      -> "application/x-httpd-imap"
  ".inf"       -> "application/inf"
  ".ins"       -> "application/x-internett-signup"
  ".ip"        -> "application/x-ip2"
  ".isu"       -> "video/x-isvideo"
  ".it"        -> "audio/it"
  ".iv"        -> "application/x-inventor"
  ".ivr"       -> "i-world/i-vrml"
  ".ivy"       -> "application/x-livescreen"
  ".jam"       -> "audio/x-jam"
  ".jav"       -> "text/plain"
  ".java"      -> "text/plain"
  ".jcm"       -> "application/x-java-commerce"
  ".jfif"      -> "image/jpeg"
  ".jfif-tbnl" -> "image/jpeg"
  ".jpe"       -> "image/jpeg"
  ".jpeg"      -> "image/jpeg"
  ".jpg"       -> "image/jpeg"
  ".jps"       -> "image/x-jps"
  ".js"        -> "application/x-javascript"
  ".jut"       -> "image/jutvision"
  ".kar"       -> "audio/midi"
  ".ksh"       -> "application/x-ksh"
  ".la"        -> "audio/nspaudio"
  ".lam"       -> "audio/x-liveaudio"
  ".latex"     -> "application/x-latex"
  ".lha"       -> "application/lha"
  ".lhx"       -> "application/octet-stream"
  ".list"      -> "text/plain"
  ".lma"       -> "audio/nspaudio"
  ".log"       -> "text/plain"
  ".lsp"       -> "application/x-lisp"
  ".lst"       -> "text/plain"
  ".lsx"       -> "text/x-la-asf"
  ".ltx"       -> "application/x-latex"
  ".lzh"       -> "application/octet-stream"
  ".lzx"       -> "application/lzx"
  ".m"         -> "text/plain"
  ".m1v"       -> "video/mpeg"
  ".m2a"       -> "audio/mpeg"
  ".m2v"       -> "video/mpeg"
  ".m3u"       -> "audio/x-mpequrl"
  ".man"       -> "application/x-troff-man"
  ".map"       -> "application/x-navimap"
  ".mar"       -> "text/plain"
  ".mbd"       -> "application/mbedlet"
  ".mc$"       -> "application/x-magic-cap-package-1.0"
  ".mcd"       -> "application/mcad"
  ".mcf"       -> "image/vasa"
  ".mcp"       -> "application/netmc"
  ".me"        -> "application/x-troff-me"
  ".mht"       -> "message/rfc822"
  ".mhtml"     -> "message/rfc822"
  ".mid"       -> "application/x-midi"
  ".midi"      -> "application/x-midi"
  ".mif"       -> "application/x-frame"
  ".mime"      -> "message/rfc822"
  ".mjf"       -> "audio/x-vnd.audioexplosion.mjuicemediafile"
  ".mjpg"      -> "video/x-motion-jpeg"
  ".mm"        -> "application/base64"
  ".mme"       -> "application/base64"
  ".mod"       -> "audio/mod"
  ".moov"      -> "video/quicktime"
  ".mov"       -> "video/quicktime"
  ".movie"     -> "video/x-sgi-movie"
  ".mp2"       -> "audio/mpeg"
  ".mp3"       -> "audio/mpeg3"
  ".mpa"       -> "audio/mpeg"
  ".mpc"       -> "application/x-project"
  ".mpe"       -> "video/mpeg"
  ".mpeg"      -> "video/mpeg"
  ".mpg"       -> "audio/mpeg"
  ".mpga"      -> "audio/mpeg"
  ".mpp"       -> "application/vnd.ms-project"
  ".mpt"       -> "application/x-project"
  ".mpv"       -> "application/x-project"
  ".mpx"       -> "application/x-project"
  ".mrc"       -> "application/marc"
  ".ms"        -> "application/x-troff-ms"
  ".mv"        -> "video/x-sgi-movie"
  ".my"        -> "audio/make"
  ".mzz"       -> "application/x-vnd.audioexplosion.mzz"
  ".nap"       -> "image/naplps"
  ".naplps"    -> "image/naplps"
  ".nc"        -> "application/x-netcdf"
  ".ncm"       -> "application/vnd.nokia.configuration-message"
  ".nif"       -> "image/x-niff"
  ".niff"      -> "image/x-niff"
  ".nix"       -> "application/x-mix-transfer"
  ".nsc"       -> "application/x-conference"
  ".nvd"       -> "application/x-navidoc"
  ".o"         -> "application/octet-stream"
  ".oda"       -> "application/oda"
  ".omc"       -> "application/x-omc"
  ".omcd"      -> "application/x-omcdatamaker"
  ".omcr"      -> "application/x-omcregerator"
  ".p"         -> "text/x-pascal"
  ".p10"       -> "application/pkcs10"
  ".p12"       -> "application/pkcs-12"
  ".p7a"       -> "application/x-pkcs7-signature"
  ".p7c"       -> "application/pkcs7-mime"
  ".p7m"       -> "application/pkcs7-mime"
  ".p7r"       -> "application/x-pkcs7-certreqresp"
  ".p7s"       -> "application/pkcs7-signature"
  ".part"      -> "application/pro_eng"
  ".pas"       -> "text/pascal"
  ".pbm"       -> "image/x-portable-bitmap"
  ".pcl"       -> "application/vnd.hp-pcl"
  ".pct"       -> "image/x-pict"
  ".pcx"       -> "image/x-pcx"
  ".pdb"       -> "chemical/x-pdb"
  ".pdf"       -> "application/pdf"
  ".pfunk"     -> "audio/make"
  ".pgm"       -> "image/x-portable-graymap"
  ".pic"       -> "image/pict"
  ".pict"      -> "image/pict"
  ".pkg"       -> "application/x-newton-compatible-pkg"
  ".pko"       -> "application/vnd.ms-pki.pko"
  ".pl"        -> "text/plain"
  ".plx"       -> "application/x-pixclscript"
  ".pm"        -> "image/x-xpixmap"
  ".pm4"       -> "application/x-pagemaker"
  ".pm5"       -> "application/x-pagemaker"
  ".png"       -> "image/png"
  ".pnm"       -> "application/x-portable-anymap"
  ".pot"       -> "application/mspowerpoint"
  ".pov"       -> "model/x-pov"
  ".ppa"       -> "application/vnd.ms-powerpoint"
  ".ppm"       -> "image/x-portable-pixmap"
  ".pps"       -> "application/mspowerpoint"
  ".ppt"       -> "application/mspowerpoint"
  ".ppz"       -> "application/mspowerpoint"
  ".pre"       -> "application/x-freelance"
  ".prt"       -> "application/pro_eng"
  ".ps"        -> "application/postscript"
  ".psd"       -> "application/octet-stream"
  ".pvu"       -> "paleovu/x-pv"
  ".pwz"       -> "application/vnd.ms-powerpoint"
  ".py"        -> "text/x-script.phyton"
  ".pyc"       -> "applicaiton/x-bytecode.python"
  ".qcp"       -> "audio/vnd.qcelp"
  ".qd3"       -> "x-world/x-3dmf"
  ".qd3d"      -> "x-world/x-3dmf"
  ".qif"       -> "image/x-quicktime"
  ".qt"        -> "video/quicktime"
  ".qtc"       -> "video/x-qtc"
  ".qti"       -> "image/x-quicktime"
  ".qtif"      -> "image/x-quicktime"
  ".ra"        -> "audio/x-pn-realaudio"
  ".ram"       -> "audio/x-pn-realaudio"
  ".ras"       -> "application/x-cmu-raster"
  ".rast"      -> "image/cmu-raster"
  ".rexx"      -> "text/x-script.rexx"
  ".rf"        -> "image/vnd.rn-realflash"
  ".rgb"       -> "image/x-rgb"
  ".rm"        -> "application/vnd.rn-realmedia"
  ".rmi"       -> "audio/mid"
  ".rmm"       -> "audio/x-pn-realaudio"
  ".rmp"       -> "audio/x-pn-realaudio"
  ".rng"       -> "application/ringing-tones"
  ".rnx"       -> "application/vnd.rn-realplayer"
  ".roff"      -> "application/x-troff"
  ".rp"        -> "image/vnd.rn-realpix"
  ".rpm"       -> "audio/x-pn-realaudio-plugin"
  ".rt"        -> "text/richtext"
  ".rtf"       -> "application/rtf"
  ".rtx"       -> "application/rtf"
  ".rv"        -> "video/vnd.rn-realvideo"
  ".s"         -> "text/x-asm"
  ".s3m"       -> "audio/s3m"
  ".saveme"    -> "application/octet-stream"
  ".sbk"       -> "application/x-tbook"
  ".scm"       -> "application/x-lotusscreencam"
  ".sdml"      -> "text/plain"
  ".sdp"       -> "application/sdp"
  ".sdr"       -> "application/sounder"
  ".sea"       -> "application/sea"
  ".set"       -> "application/set"
  ".sgm"       -> "text/sgml"
  ".sgml"      -> "text/sgml"
  ".sh"        -> "application/x-bsh"
  ".shar"      -> "application/x-bsh"
  ".shtml"     -> "text/html"
  ".sid"       -> "audio/x-psid"
  ".sit"       -> "application/x-sit"
  ".skd"       -> "application/x-koan"
  ".skm"       -> "application/x-koan"
  ".skp"       -> "application/x-koan"
  ".skt"       -> "application/x-koan"
  ".sl"        -> "application/x-seelogo"
  ".smi"       -> "application/smil"
  ".smil"      -> "application/smil"
  ".snd"       -> "audio/basic"
  ".sol"       -> "application/solids"
  ".spc"       -> "application/x-pkcs7-certificates"
  ".spl"       -> "application/futuresplash"
  ".spr"       -> "application/x-sprite"
  ".sprite"    -> "application/x-sprite"
  ".src"       -> "application/x-wais-source"
  ".ssi"       -> "text/x-server-parsed-html"
  ".ssm"       -> "application/streamingmedia"
  ".sst"       -> "application/vnd.ms-pki.certstore"
  ".step"      -> "application/step"
  ".stl"       -> "application/sla"
  ".stp"       -> "application/step"
  ".sv4cpio"   -> "application/x-sv4cpio"
  ".sv4crc"    -> "application/x-sv4crc"
  ".svf"       -> "image/vnd.dwg"
  ".svr"       -> "application/x-world"
  ".swf"       -> "application/x-shockwave-flash"
  ".t"         -> "application/x-troff"
  ".talk"      -> "text/x-speech"
  ".tar"       -> "application/x-tar"
  ".tbk"       -> "application/toolbook"
  ".tcl"       -> "application/x-tcl"
  ".tcsh"      -> "text/x-script.tcsh"
  ".tex"       -> "application/x-tex"
  ".texi"      -> "application/x-texinfo"
  ".texinfo"   -> "application/x-texinfo"
  ".text"      -> "application/plain"
  ".tgz"       -> "application/gnutar"
  ".tif"       -> "image/tiff"
  ".tiff"      -> "image/tiff"
  ".tr"        -> "application/x-troff"
  ".tsi"       -> "audio/tsp-audio"
  ".tsp"       -> "application/dsptype"
  ".tsv"       -> "text/tab-separated-values"
  ".turbot"    -> "image/florian"
  ".txt"       -> "text/plain"
  ".uil"       -> "text/x-uil"
  ".uni"       -> "text/uri-list"
  ".unis"      -> "text/uri-list"
  ".unv"       -> "application/i-deas"
  ".uri"       -> "text/uri-list"
  ".uris"      -> "text/uri-list"
  ".ustar"     -> "application/x-ustar"
  ".uu"        -> "application/octet-stream"
  ".uue"       -> "text/x-uuencode"
  ".vcd"       -> "application/x-cdlink"
  ".vcs"       -> "text/x-vcalendar"
  ".vda"       -> "application/vda"
  ".vdo"       -> "video/vdo"
  ".vew"       -> "application/groupwise"
  ".viv"       -> "video/vivo"
  ".vivo"      -> "video/vivo"
  ".vmd"       -> "application/vocaltec-media-desc"
  ".vmf"       -> "application/vocaltec-media-file"
  ".voc"       -> "audio/voc"
  ".vos"       -> "video/vosaic"
  ".vox"       -> "audio/voxware"
  ".vqe"       -> "audio/x-twinvq-plugin"
  ".vqf"       -> "audio/x-twinvq"
  ".vql"       -> "audio/x-twinvq-plugin"
  ".vrml"      -> "application/x-vrml"
  ".vrt"       -> "x-world/x-vrt"
  ".vsd"       -> "application/x-visio"
  ".vst"       -> "application/x-visio"
  ".vsw"       -> "application/x-visio"
  ".w60"       -> "application/wordperfect6.0"
  ".w61"       -> "application/wordperfect6.1"
  ".w6w"       -> "application/msword"
  ".wav"       -> "audio/wav"
  ".wb1"       -> "application/x-qpro"
  ".wbmp"      -> "image/vnd.wap.wbmp"
  ".web"       -> "application/vnd.xara"
  ".wiz"       -> "application/msword"
  ".wk1"       -> "application/x-123"
  ".wmf"       -> "windows/metafile"
  ".wml"       -> "text/vnd.wap.wml"
  ".wmlc"      -> "application/vnd.wap.wmlc"
  ".wmls"      -> "text/vnd.wap.wmlscript"
  ".wmlsc"     -> "application/vnd.wap.wmlscriptc"
  ".word"      -> "application/msword"
  ".wp"        -> "application/wordperfect"
  ".wp5"       -> "application/wordperfect"
  ".wp6"       -> "application/wordperfect"
  ".wpd"       -> "application/wordperfect"
  ".wq1"       -> "application/x-lotus"
  ".wri"       -> "application/mswrite"
  ".wrl"       -> "application/x-world"
  ".wrz"       -> "model/vrml"
  ".wsc"       -> "text/scriplet"
  ".wsrc"      -> "application/x-wais-source"
  ".wtk"       -> "application/x-wintalk"
  ".xbm"       -> "image/x-xbitmap"
  ".xdr"       -> "video/x-amt-demorun"
  ".xgz"       -> "xgl/drawing"
  ".xif"       -> "image/vnd.xiff"
  ".xl"        -> "application/excel"
  ".xla"       -> "application/excel"
  ".xlb"       -> "application/excel"
  ".xlc"       -> "application/excel"
  ".xld"       -> "application/excel"
  ".xlk"       -> "application/excel"
  ".xll"       -> "application/excel"
  ".xlm"       -> "application/excel"
  ".xls"       -> "application/excel"
  ".xlt"       -> "application/excel"
  ".xlv"       -> "application/excel"
  ".xlw"       -> "application/excel"
  ".xm"        -> "audio/xm"
  ".xml"       -> "application/xml"
  ".xmz"       -> "xgl/movie"
  ".xpix"      -> "application/x-vnd.ls-xpix"
  ".xpm"       -> "image/x-xpixmap"
  ".x-png"     -> "image/png"
  ".xsr"       -> "video/x-amt-showrun"
  ".xwd"       -> "image/x-xwd"
  ".xyz"       -> "chemical/x-pdb"
  ".z"         -> "application/x-compress"
  ".zip"       -> "application/x-compressed"
  ".zoo"       -> "application/octet-stream"
  ".zsh"       -> "text/x-script.zsh"
  _            -> "application/octet-stream"