mini-http-server: Handle nonexistent files decently

2 files changed, 14 insertions, 3 deletions

diff --git a/mini-http-server/Network/HTTP/Server/Mini/Printer.hs b/mini-http-server/Network/HTTP/Server/Mini/Printer.hs
index 77b88ce..442d768 100644
--- a/mini-http-server/Network/HTTP/Server/Mini/Printer.hs
+++ b/mini-http-server/Network/HTTP/Server/Mini/Printer.hs
@@ -5,19 +5,27 @@ import Data.ByteString (ByteString)
 import Data.ByteString qualified as BS
 import Data.ByteString.Lazy qualified as BSL
 import Data.ByteString.Builder qualified as BSB
+import GHC.IO.Exception (IOException(..), IOErrorType(..))
 import Network.Socket
 import Network.Socket.ByteString
+import System.IO.Error (catchIOError)
 
 import Network.HTTP.Server.Mini.Types
-import System.IO.Error (catchIOError)
 
 
 sendResponse :: Socket -> Response -> IO ()
 sendResponse conn (Response status hdrs (BodyLBS body)) =
   sendResponseChunks conn status hdrs body
-sendResponse conn (Response status hdrs (BodyFile path)) =
+sendResponse conn (Response status hdrs (BodyFile path)) = do
   -- lazy IO is fine here because the whole thing is traversed before the end of this function in sendMany
-  sendResponseChunks conn status hdrs =<< BSL.readFile path
+  elazyContents <-
+    catchIOError (Right <$> BSL.readFile path)
+      (\e -> case ioe_type e of
+               NoSuchThing -> return (Left (status404, "File not found"))
+               _ -> return (Left (status500, "Something went wrong")))
+  case elazyContents of
+    Right lazyContents -> sendResponseChunks conn status hdrs lazyContents
+    Left (status', text) -> sendResponseChunks conn status' [] text
 
 sendResponseChunks :: Socket -> Status -> [(Header, ByteString)] -> BSL.ByteString -> IO ()
 sendResponseChunks conn (Status code reason) hdrs body =
diff --git a/mini-http-server/Network/HTTP/Server/Mini/Types.hs b/mini-http-server/Network/HTTP/Server/Mini/Types.hs
index 94e113f..42a1085 100644
--- a/mini-http-server/Network/HTTP/Server/Mini/Types.hs
+++ b/mini-http-server/Network/HTTP/Server/Mini/Types.hs
@@ -57,6 +57,9 @@ status200 = Status 200 "OK"
 status404 :: Status
 status404 = Status 404 "Not Found"
 
+status500 :: Status
+status500 = Status 500 "Internal Server Error"
+
 responseLBS :: Status -> [(Header, ByteString)] -> LazyByteString -> Response
 responseLBS status hdrs = Response status hdrs . BodyLBS