-- | Module containing a small, simple http file server for testing and preview -- purposes. module Network.Hakyll.SimpleServer ( simpleServer ) where import Prelude hiding (log) import Network import Control.Monad (forever, mapM_) import Control.Monad.Reader (ReaderT, runReaderT, ask, liftIO) import System.IO (Handle, hClose, hGetLine, hPutStr, hPutStrLn, stderr) import System.Directory (doesFileExist, doesDirectoryExist) import Control.Concurrent (forkIO) import Control.Concurrent.Chan (Chan, newChan, readChan, writeChan) import System.FilePath (takeExtension) import qualified Data.ByteString.Char8 as B import qualified Data.Map as M import Text.Hakyll.Util import Text.Hakyll.Regex -- | Function to log from a chan. log :: Chan String -> IO () log logChan = forever (readChan logChan >>= hPutStrLn stderr) -- | General server configuration. data ServerConfig = ServerConfig { documentRoot :: FilePath , portNumber :: PortNumber , logChannel :: Chan String } -- | Custom monad stack. type Server = ReaderT ServerConfig IO -- | Simple representation of a HTTP request. data Request = Request { requestMethod :: B.ByteString , requestURI :: B.ByteString , requestVersion :: B.ByteString } deriving (Ord, Eq) instance Show Request where show request = (B.unpack $ requestMethod request) ++ " " ++ (B.unpack $ requestURI request) ++ " " ++ (B.unpack $ requestVersion request) -- | Read a HTTP request from a 'Handle'. For now, this will ignore the request -- headers and body. readRequest :: Handle -> Server Request readRequest handle = do requestLine <- liftIO $ hGetLine handle let [method, uri, version] = map trim $ splitRegex " " requestLine return $ Request { requestMethod = B.pack method , requestURI = B.pack uri , requestVersion = B.pack version } -- | Simple representation of the HTTP response we send back. data Response = Response { responseVersion :: B.ByteString , responseStatusCode :: Int , responsePhrase :: B.ByteString , responseHeaders :: M.Map B.ByteString B.ByteString , responseBody :: B.ByteString } deriving (Ord, Eq) instance Show Response where show response = (B.unpack $ responseVersion response) ++ " " ++ (show $ responseStatusCode response) ++ " " ++ (B.unpack $ responsePhrase response) -- | A default response. defaultResponse :: Response defaultResponse = Response { responseVersion = B.pack "HTTP/1.1" , responseStatusCode = 0 , responsePhrase = B.empty , responseHeaders = M.empty , responseBody = B.empty } -- | Create a response for a given HTTP request. createResponse :: Request -> Server Response createResponse request | requestMethod request == B.pack "GET" = createGetResponse request | otherwise = return $ createErrorResponse 501 (B.pack "Not Implemented") -- | Create a simple error response. createErrorResponse :: Int -- ^ Error code. -> B.ByteString -- ^ Error phrase. -> Response -- ^ Result. createErrorResponse statusCode phrase = defaultResponse { responseStatusCode = statusCode , responsePhrase = phrase , responseHeaders = M.singleton (B.pack "Content-Type") (B.pack "text/html") , responseBody = B.pack $ "
" ++ (B.unpack phrase) ++ "
" } -- | Create a simple get response. createGetResponse :: Request -> Server Response createGetResponse request = do -- Construct the complete fileName of the requested resource. config <- ask let uri = B.unpack (requestURI request) log' = writeChan (logChannel config) isDirectory <- liftIO $ doesDirectoryExist $ documentRoot config ++ uri let fileName = (documentRoot config) ++ if isDirectory then uri ++ "/index.html" else uri create200 = do body <- B.readFile fileName let headers = [ (B.pack "Content-Length", B.pack $ show $ B.length body) ] ++ getMIMEHeader fileName return $ defaultResponse { responseStatusCode = 200 , responsePhrase = B.pack "OK" , responseHeaders = (responseHeaders defaultResponse) `M.union` M.fromList headers , responseBody = body } -- Called when an error occurs during the creation of a 200 response. create500 e = do log' $ "Internal Error: " ++ show e return $ createErrorResponse 500 (B.pack "Internal Server Error") -- Send back the page if found. exists <- liftIO $ doesFileExist fileName if exists then do response <- liftIO $ catch create200 create500 return response else do liftIO $ log' $ "Not Found: " ++ fileName return $ createErrorResponse 404 (B.pack "Not Found") -- | Get the mime header for a certain filename. This is based on the extension -- of the given 'FilePath'. getMIMEHeader :: FilePath -> [(B.ByteString, B.ByteString)] getMIMEHeader fileName = case result of (Just x) -> [(B.pack "Content-Type", B.pack x)] Nothing -> [] where result = lookup (takeExtension fileName) [ (".css", "text/css") , (".gif", "image/gif") , (".htm", "text/html") , (".html", "text/html") , (".jpeg", "image/jpeg") , (".jpg", "image/jpeg") , (".js", "text/javascript") , (".png", "image/png") , (".txt", "text/plain") , (".xml", "text/xml") ] -- | Respond to an incoming request. respond :: Handle -> Server () respond handle = do -- Read the request and create a response. request <- readRequest handle response <- createResponse request -- Generate some output. config <- ask liftIO $ writeChan (logChannel config) $ show request ++ " => " ++ show response -- Send the response back to the handle. liftIO $ putResponse response where putResponse response = do B.hPutStr handle $ B.intercalate (B.pack " ") [ responseVersion response , B.pack $ show $ responseStatusCode response , responsePhrase response ] hPutStr handle "\r\n" mapM_ putHeader (M.toList $ responseHeaders response) hPutStr handle "\r\n" B.hPutStr handle $ responseBody response hPutStr handle "\r\n" hClose handle putHeader (key, value) = B.hPutStr handle $ key `B.append` B.pack ": " `B.append` value `B.append` B.pack "\r\n" -- | Start a simple http server on the given 'PortNumber', serving the given -- directory. simpleServer :: PortNumber -> FilePath -> IO () simpleServer port root = do -- Channel to send logs to logChan <- newChan let config = ServerConfig { documentRoot = root , portNumber = port , logChannel = logChan } -- When a client connects, respond in a separate thread. listen socket = do (handle, _, _) <- accept socket forkIO (runReaderT (respond handle) config) return () -- Handle logging in a separate thread forkIO (log logChan) writeChan logChan $ "Starting hakyll server on port " ++ show port ++ "..." socket <- listenOn (PortNumber port) forever (listen socket)