1 files changed, 85 insertions, 1 deletions
diff --git a/mini-http/Network/HTTP/Server/Mini/Parser.hs b/mini-http/Network/HTTP/Server/Mini/Parser.hs
index 02da6d3..97e25c1 100644
--- a/mini-http/Network/HTTP/Server/Mini/Parser.hs
+++ b/mini-http/Network/HTTP/Server/Mini/Parser.hs
@@ -1,10 +1,20 @@
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TypeApplications #-}
 module Network.HTTP.Server.Mini.Parser where
 
+import Control.Monad (guard)
 import Control.Monad.Trans.Maybe
 import Data.ByteString (ByteString)
 import Data.ByteString qualified as BS
+import Data.ByteString.Short (ShortByteString)
+import Data.ByteString.Short qualified as SBS
+import Data.Char
+import Data.Word
+import FlatParse.Basic qualified as P
 
 import Network.HTTP.Server.Mini.Types
+import Network.HTTP.Server.Mini.URI
+import Network.HTTP.Server.Mini.Util
 
 
 readRequest :: Monad m => Int -> (Int -> m ByteString) -> m (Maybe Request)
@@ -13,7 +23,71 @@ readRequest maxsize recv = runMaybeT $ do
   hoistMaybe (parseRequest bs)
 
 parseRequest :: ByteString -> Maybe Request
-parseRequest = _
+parseRequest bs =
+  case P.runParser pRequest bs of
+    P.OK req rest | BS.null rest -> Just req
+    _ -> Nothing
+
+pRequest :: P.Parser e Request
+pRequest = do
+  (method, uri) <- pFirstLine
+  headers <- P.many pHeader
+  let (path, query) = parseURI uri
+  return Request { reqMethod = method
+                 , reqURI = uri
+                 , reqHeaders = headers
+                 , reqPath = path
+                 , reqQuery = query }
+
+pFirstLine :: P.Parser e (ShortByteString, ByteString)
+pFirstLine = do
+  method <- pTakeUntil (ord8 ' ')
+  guard (BS.length method <= 32)  -- will put it in an SBS later
+  P.word8 32
+  uri <- pTakeUntil (ord8 ' ')
+  P.word8 32
+  $(P.bytes (map (fromIntegral @Int @Word . ord) "HTTP/1."))
+  version <- P.anyWord8
+  guard (version == ord8 '0' || version == ord8 '1')
+  pNewline
+  return (SBS.pack (map toAsciiUpperCase (BS.unpack method)), uri)
+
+pHeader :: P.Parser e (Header, ByteString)
+pHeader = do
+  key <- pTakeUntil (ord8 ':')
+  guard (BS.length key <= 128)  -- will put it in an SBS later
+  P.word8 (ord8 ':')
+  P.skipMany (P.satisfy isLinearSpace)
+  value <- pValue []
+  return (SBS.pack (map toAsciiLowerCase (BS.unpack key)), value)
+  where
+    pValue revlines = do
+      line <- trimCR <$> pTakeUntil 10
+      P.word8 10
+      P.withOption (P.lookahead (P.skipSatisfyAscii isLinearSpace))
+        (\_ -> pValue (line : revlines))
+        (return (BS.concat (reverse (line : revlines))))
+
+    trimCR bs
+      | len >= 1, bs `BS.index` (len - 1) == 13 = BS.take (len - 1) bs
+      | otherwise = bs
+      where len = BS.length bs
+
+isLinearSpace :: Char -> Bool
+isLinearSpace c = c == ' ' || c == '\t'
+
+pTakeUntil :: Word8 -> P.Parser e ByteString
+pTakeUntil term = do
+  midx <- P.lookahead (BS.elemIndex term <$> P.takeRest)
+  case midx of
+    Just idx -> P.take idx
+    Nothing -> P.failed
+
+pNewline :: P.Parser e ()
+pNewline = P.withAnyWord8 $ \case
+  10 -> return ()
+  13 -> P.word8 10
+  _ -> P.failed
 
 readUntilTerminator :: Monad m => Int -> (Int -> m ByteString) -> [ByteString] -> m (Maybe ByteString)
 readUntilTerminator 0 _ _ = return Nothing
@@ -76,3 +150,13 @@ findTerminator bs =
             -- [i+2] is read twice if this check fails, but LF CR (!=LF) will be very rare so it's fine
             13 | bs `BS.index` (i+2) == 10 -> FoundTerm (i+1)
             _ -> go is
+
+toAsciiUpperCase :: Word8 -> Word8
+toAsciiUpperCase c
+  | ord8 'a' <= c, c <= ord8 'z' = c - 32
+  | otherwise = c
+
+toAsciiLowerCase :: Word8 -> Word8
+toAsciiLowerCase c
+  | ord8 'A' <= c, c <= ord8 'Z' = c + 32
+  | otherwise = c