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-- | Module containing a small, simple http file server for testing and preview
-- purposes.
module Network.Hakyll.SimpleServer
( simpleServer
) where
import Network
import Control.Monad (forever, mapM_)
import Control.Monad.Reader (ReaderT, runReaderT, ask, liftIO)
import System.IO (Handle, hClose, hGetLine, hPutStr)
import System.Directory (doesFileExist, doesDirectoryExist)
import Control.Concurrent (forkIO)
import System.FilePath (takeExtension)
import qualified Data.ByteString.Char8 as B
import qualified Data.Map as M
import Text.Hakyll.Util
-- | General server configuration.
data ServerConfig = ServerConfig { documentRoot :: FilePath
, portNumber :: PortNumber
} deriving (Show, Eq, Ord)
-- | 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 $ split " " 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 $ "<html> <head> <title>" ++ show statusCode ++ "</title> </head>"
++ "<body> <h1>" ++ show statusCode ++ "</h1>\n"
++ "<p>" ++ (B.unpack phrase) ++ "</p> </body> </html>"
}
-- | 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)
isDirectory <- liftIO $ doesDirectoryExist $ documentRoot config ++ uri
let fileName = (documentRoot config) ++ if isDirectory then uri ++ "/index.html"
else uri
-- Send back the page if found.
exists <- liftIO $ doesFileExist fileName
if exists then do response <- liftIO $ catch (create200 fileName) create500
return response
else return $ createErrorResponse 404 (B.pack "Not Found")
where create200 fileName = 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 putStrLn $ "Internal Error: " ++ show e
return $ createErrorResponse 500 (B.pack "Internal Server Error")
-- | 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.
liftIO $ putStrLn $ 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
putStrLn $ "Starting hakyll server on port " ++ show port ++ "..."
socket <- listenOn (PortNumber port)
forever (listen socket)
where -- A default configuration.
config = ServerConfig { documentRoot = root
, portNumber = port
}
-- When a client connects, respond in a separate thread.
listen socket = do (handle, _, _) <- accept socket
forkIO (runReaderT (respond handle) config)
return ()
|
