forked from GitHub/gf-core
157 lines
6.2 KiB
Haskell
157 lines
6.2 KiB
Haskell
{-# LANGUAGE DeriveDataTypeable #-}
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import PGF (PGF)
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import qualified PGF
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import FastCGIUtils
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import URLEncoding
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import Network.CGI
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import Text.JSON
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import qualified Codec.Binary.UTF8.String as UTF8 (encodeString, decodeString)
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import Control.Monad
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import Data.Char
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import qualified Data.Map as Map
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import Data.Maybe
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grammarFile :: FilePath
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grammarFile = "grammar.pgf"
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main :: IO ()
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main = do initFastCGI
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r <- newDataRef
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loopFastCGI (handleErrors (handleCGIErrors (fcgiMain r)))
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fcgiMain :: DataRef PGF -> CGI CGIResult
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fcgiMain ref = getData (liftIO . PGF.readPGF) ref grammarFile >>= cgiMain
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cgiMain :: PGF -> CGI CGIResult
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cgiMain pgf =
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do path <- pathInfo
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json <- case path of
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"/parse" -> return (doParse pgf) `ap` getText `ap` getCat `ap` getFrom
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"/complete" -> return (doComplete pgf) `ap` getText `ap` getCat `ap` getFrom `ap` getLimit
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"/linearize" -> return (doLinearize pgf) `ap` getTree `ap` getTo
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"/translate" -> return (doTranslate pgf) `ap` getText `ap` getCat `ap` getFrom `ap` getTo
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"/grammar" -> return (doGrammar pgf) `ap` requestAcceptLanguage
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_ -> throwCGIError 404 "Not Found" ["Resource not found: " ++ path]
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outputJSON json
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where
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getText :: CGI String
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getText = liftM (maybe "" (urlDecodeUnicode . UTF8.decodeString)) $ getInput "input"
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getTree :: CGI PGF.Tree
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getTree = do mt <- getInput "tree"
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t <- maybe (throwCGIError 400 "No tree given" ["No tree given"]) return mt
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maybe (throwCGIError 400 "Bad tree" ["Bad tree: " ++ t]) return (PGF.readTree t)
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getCat :: CGI (Maybe PGF.Category)
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getCat =
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do mcat <- getInput "cat"
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case mcat of
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Just "" -> return Nothing
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Just cat | cat `notElem` PGF.categories pgf ->
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throwCGIError 400 "Unknown category" ["Unknown category: " ++ cat]
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_ -> return mcat
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getFrom :: CGI (Maybe PGF.Language)
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getFrom = getLang "from"
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getTo :: CGI (Maybe PGF.Language)
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getTo = getLang "to"
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getLimit :: CGI (Maybe Int)
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getLimit = readInput "limit"
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getLang :: String -> CGI (Maybe PGF.Language)
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getLang i =
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do mlang <- getInput i
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case mlang of
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Just "" -> return Nothing
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Just lang | lang `notElem` PGF.languages pgf ->
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throwCGIError 400 "Unknown language" ["Unknown language: " ++ lang]
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_ -> return mlang
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doTranslate :: PGF -> String -> Maybe PGF.Category -> Maybe PGF.Language -> Maybe PGF.Language -> JSValue
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doTranslate pgf input mcat mfrom mto = showJSON $ map toJSObject
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[[("from",from),("to",to),("text",output)]
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| (from,trees) <- parse' pgf input mcat mfrom,
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tree <- trees,
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(to,output) <- linearize' pgf mto tree]
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doParse :: PGF -> String -> Maybe PGF.Category -> Maybe PGF.Language -> JSValue
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doParse pgf input mcat mfrom = showJSON $ map toJSObject
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[[("from",from),("tree",PGF.showTree tree)]
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| (from,trees) <- parse' pgf input mcat mfrom,
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tree <- trees ]
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doComplete :: PGF -> String -> Maybe PGF.Category -> Maybe PGF.Language -> Maybe Int -> JSValue
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doComplete pgf input mcat mfrom mlimit = showJSON $ map toJSObject $ limit
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[[("from",from),("text",text)]
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| (from,compls) <- complete' pgf input mcat mfrom,
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text <- compls]
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where
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limit xs = maybe xs (\n -> take n xs) mlimit
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doLinearize :: PGF -> PGF.Tree -> Maybe PGF.Language -> JSValue
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doLinearize pgf tree mto = showJSON $ map toJSObject
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[[("to",to),("text",text)] | (to,text) <- linearize' pgf mto tree]
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doGrammar :: PGF -> Maybe (Accept Language) -> JSValue
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doGrammar pgf macc = showJSON $ toJSObject
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[("name", showJSON (PGF.abstractName pgf)),
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("userLanguage", showJSON (selectLanguage pgf macc)),
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("categories", showJSON categories),
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("languages", showJSON languages)]
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where languages = map toJSObject
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[[("name", showJSON l),
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("languageCode", showJSON $ fromMaybe "" (PGF.languageCode pgf l)),
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("canParse", showJSON $ PGF.canParse pgf l)]
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| l <- PGF.languages pgf]
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categories = map toJSObject [[("cat", cat)] | cat <- PGF.categories pgf]
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-- * PGF utilities
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parse' :: PGF -> String -> Maybe PGF.Category -> Maybe PGF.Language -> [(PGF.Language,[PGF.Tree])]
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parse' pgf input mcat mfrom =
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[(from,ts) | from <- froms, PGF.canParse pgf from, let ts = PGF.parse pgf from cat input, not (null ts)]
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where froms = maybe (PGF.languages pgf) (:[]) mfrom
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cat = fromMaybe (PGF.startCat pgf) mcat
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complete' :: PGF -> String -> Maybe PGF.Category -> Maybe PGF.Language -> [(PGF.Language,[String])]
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complete' pgf input mcat mfrom =
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[(from,ss) | from <- froms, PGF.canParse pgf from, let ss = PGF.complete pgf from cat input, not (null ss)]
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where froms = maybe (PGF.languages pgf) (:[]) mfrom
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cat = fromMaybe (PGF.startCat pgf) mcat
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linearize' :: PGF -> Maybe PGF.Language -> PGF.Tree -> [(PGF.Language,String)]
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linearize' pgf mto tree =
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case mto of
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Nothing -> PGF.linearizeAllLang pgf tree
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Just to -> [(to,PGF.linearize pgf to tree)]
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selectLanguage :: PGF -> Maybe (Accept Language) -> PGF.Language
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selectLanguage pgf macc = case acceptable of
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[] -> case PGF.languages pgf of
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[] -> "" -- FIXME: error?
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l:_ -> l
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Language c:_ -> fromJust (langCodeLanguage pgf c)
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where langCodes = mapMaybe (PGF.languageCode pgf) (PGF.languages pgf)
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acceptable = negotiate (map Language langCodes) macc
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langCodeLanguage :: PGF -> String -> Maybe PGF.Language
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langCodeLanguage pgf code = listToMaybe [l | l <- PGF.languages pgf, PGF.languageCode pgf l == Just code]
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-- * General CGI and JSON stuff
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outputJSON :: JSON a => a -> CGI CGIResult
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outputJSON x = do setHeader "Content-Type" "text/json; charset=utf-8"
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outputStrict $ UTF8.encodeString $ encode x
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outputStrict :: String -> CGI CGIResult
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outputStrict x | x == x = output x
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| otherwise = fail "I am the pope."
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