1 files changed, 44 insertions, 0 deletions
diff --git a/mini-http-server/Network/HTTP/Server/Mini/URI.hs b/mini-http-server/Network/HTTP/Server/Mini/URI.hs
new file mode 100644
index 0000000..13d7c35
--- /dev/null
+++ b/mini-http-server/Network/HTTP/Server/Mini/URI.hs
@@ -0,0 +1,44 @@
+{-# LANGUAGE ViewPatterns #-}
+module Network.HTTP.Server.Mini.URI where
+
+import Data.ByteString (ByteString)
+import Data.ByteString qualified as BS
+
+import Network.HTTP.Server.Mini.Util
+
+
+-- | (path components, query string)
+--
+-- TODO: percent-decode
+parseURI :: ByteString -> ([ByteString], [(ByteString, ByteString)])
+parseURI = \bs ->
+  case BS.uncons bs of
+    Just ((== ord8 '/') -> True, bs1) -> goPath id bs1
+    _ -> ([], [])
+  where
+    goPath f bs
+      | BS.null bs = (f [], [])
+      | otherwise =
+          let (comp, bs1) = BS.span (\c -> c /= ord8 '/' && c /= ord8 '?') bs
+          in case BS.uncons bs1 of
+               Just ((== ord8 '/') -> True, bs2) ->
+                 goPath (f . (comp:)) bs2
+               Just ((== ord8 '?') -> True, bs2) ->
+                 (f [comp], goQuery bs2)
+               _ -> (f [comp], [])
+
+    goQuery bs
+      | BS.null bs = []
+      | Just ((== ord8 '&') -> True, bs1) <- BS.uncons bs = goQuery bs1
+      | otherwise =
+          let (key, bs1) = BS.span (\c -> c /= ord8 '=' && c /= ord8 '&') bs
+          in case BS.uncons bs1 of
+               Just ((== ord8 '=') -> True, bs2) ->
+                 let (val, bs3) = BS.span (\c -> c /= ord8 '&') bs2
+                 in case BS.uncons bs3 of
+                      Just (_, bs4) -> (key, val) : goQuery bs4
+                      Nothing -> [(key, val)]
+               Just ((== ord8 '&') -> True, bs2) ->
+                 (key, BS.empty) : goQuery bs2
+               _ ->
+                 [(key, BS.empty)]