module Network.HTTP.Lucu.MIMEType.Guess
( ExtMap
, guessTypeByFileName
, parseExtMapFile
, serializeExtMap
)
where
import qualified Data.ByteString.Lazy.Char8 as B
import qualified Data.Map as M
import Data.Map (Map)
import Data.Maybe
import Language.Haskell.Pretty
import Language.Haskell.Syntax
import Network.HTTP.Lucu.MIMEType
import Network.HTTP.Lucu.Parser
import Network.HTTP.Lucu.Parser.Http
import Network.HTTP.Lucu.Utils
import System.IO
type ExtMap = Map String MIMEType
guessTypeByFileName :: ExtMap -> FilePath -> Maybe MIMEType
guessTypeByFileName extMap fpath
= extMap `seq` fpath `seq`
let ext = last $ splitBy (== '.') fpath
in
M.lookup ext extMap >>= return
parseExtMapFile :: FilePath -> IO ExtMap
parseExtMapFile fpath
= fpath `seq`
do file <- B.readFile fpath
case parse (allowEOF extMapP) file of
(# Success xs, _ #)
-> return $ compile xs
(# _, input' #)
-> let near = B.unpack $ B.take 100 input'
in
fail ("Failed to parse: " ++ fpath ++ " (near: " ++ near ++ ")")
extMapP :: Parser [ (MIMEType, [String]) ]
extMapP = do xs <- many (comment <|> validLine <|> emptyLine)
eof
return $ catMaybes xs
where
spc = oneOf " \t"
comment = do many spc
char '#'
many $ satisfy (/= '\n')
return Nothing
validLine = do many spc
mime <- mimeTypeP
many spc
exts <- sepBy token (many spc)
return $ Just (mime, exts)
emptyLine = oneOf " \t\n" >> return Nothing
compile :: [ (MIMEType, [String]) ] -> Map String MIMEType
compile = M.fromList . foldr (++) [] . map tr
where
tr :: (MIMEType, [String]) -> [ (String, MIMEType) ]
tr (mime, exts) = [ (ext, mime) | ext <- exts ]
serializeExtMap :: ExtMap -> String -> String -> String
serializeExtMap extMap moduleName variableName
= let hsModule = HsModule undefined modName (Just exports) imports decls
modName = Module moduleName
exports = [HsEVar (UnQual (HsIdent variableName))]
imports = [ HsImportDecl undefined (Module "Network.HTTP.Lucu.MIMEType") False Nothing (Just (False, []))
, HsImportDecl undefined (Module "Network.HTTP.Lucu.MIMEType.Guess") False Nothing Nothing
, HsImportDecl undefined (Module "Data.Map") True (Just (Module "M")) Nothing
]
decls = [ HsTypeSig undefined [HsIdent variableName]
(HsQualType []
(HsTyCon (UnQual (HsIdent "ExtMap"))))
, HsFunBind [HsMatch undefined (HsIdent variableName)
[] (HsUnGuardedRhs extMapExp) []]
]
extMapExp = HsApp (HsVar (Qual (Module "M") (HsIdent "fromList"))) (HsList records)
comment = "{- !!! WARNING !!!\n"
++ " This file is automatically generated.\n"
++ " DO NOT EDIT BY HAND OR YOU WILL REGRET -}\n\n"
in
comment ++ prettyPrint hsModule ++ "\n"
where
records :: [HsExp]
records = map record $ M.assocs extMap
record :: (String, MIMEType) -> HsExp
record (ext, mime)
= HsTuple [HsLit (HsString ext), mimeToExp mime]
mimeToExp :: MIMEType -> HsExp
mimeToExp mt
= HsApp (HsVar (UnQual (HsIdent "read"))) (HsLit (HsString $ show mt))