From adcf7ca3cc6fcd1a98a54192905030d0fa7177d6 Mon Sep 17 00:00:00 2001
From: Keagan McClelland <keagan.mcclelland@gmail.com>
Date: Tue, 23 Nov 2021 14:09:11 -0700
Subject: [PATCH] sends 404s if we can't find the package rather than just
 blowing up and going 500

---
 src/Handler/Apps.hs      |  4 +++-
 src/Lib/PkgRepository.hs | 13 +++++++++----
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/Handler/Apps.hs b/src/Handler/Apps.hs
index 304bafa..7267d44 100644
--- a/src/Handler/Apps.hs
+++ b/src/Handler/Apps.hs
@@ -75,7 +75,9 @@ getAppR file = do
         `orThrow` sendResponseStatus status404 (NotFoundE [i|#{pkg} satisfying #{versionSpec}|])
     addPackageHeader pkg version
     void $ recordMetrics pkg version
-    (len, src) <- getPackage pkg version
+    (len, src) <- getPackage pkg version >>= \case
+        Nothing -> sendResponseStatus status404 ([i|#{pkg}@#{version} not found|] :: Text)
+        Just a  -> pure a
     addHeader "Content-Length" (show len)
     respondSource typeOctet $ src .| awaitForever sendChunkBS
 
diff --git a/src/Lib/PkgRepository.hs b/src/Lib/PkgRepository.hs
index f5debcd..56a7251 100644
--- a/src/Lib/PkgRepository.hs
+++ b/src/Lib/PkgRepository.hs
@@ -96,7 +96,8 @@ import           UnliftIO                       ( MonadUnliftIO
                                                 )
 import           UnliftIO                       ( tryPutMVar )
 import           UnliftIO.Concurrent            ( forkIO )
-import           UnliftIO.Directory             ( getFileSize
+import           UnliftIO.Directory             ( doesPathExist
+                                                , getFileSize
                                                 , listDirectory
                                                 , removeFile
                                                 , renameFile
@@ -257,9 +258,13 @@ getHash pkg version = do
 getPackage :: (MonadResource m, MonadReader r m, Has PkgRepo r)
            => PkgId
            -> Version
-           -> m (Integer, ConduitT () ByteString m ())
+           -> m (Maybe (Integer, ConduitT () ByteString m ()))
 getPackage pkg version = do
     root <- asks pkgRepoFileRoot
     let pkgPath = root </> show pkg </> show version </> show pkg <.> "s9pk"
-    n <- getFileSize pkgPath
-    pure (n, sourceFile pkgPath)
+    found <- doesPathExist pkgPath
+    if found
+        then do
+            n <- getFileSize pkgPath
+            pure . Just $ (n, sourceFile pkgPath)
+        else pure Nothing