should work

src/Handler/Apps.hs

@@ -11,9 +11,12 @@ import           Startlude
 import           Control.Monad.Logger
 import           Data.Aeson
 import qualified Data.ByteString.Lazy as BS
+import           Data.Char
 import           Data.Conduit
 import qualified Data.Conduit.Binary  as CB
+import qualified Data.Text            as T
 import qualified GHC.Show             (Show (..))
+import           Network.HTTP.Types
 import           System.Directory
 import           Yesod.Core
 
@@ -47,7 +50,10 @@ getAppR = getApp appResourceDir
 
 getApp :: KnownSymbol a => FilePath -> Extension a -> Handler TypedContent
 getApp rootDir ext = do
-    spec <- querySpecD mostRecentVersion <$> lookupGetParam "spec"
+    specString <- T.filter (not . isSpace) . fromMaybe "*" <$> lookupGetParam "spec"
+    spec <- case readMaybe specString of
+        Nothing -> sendResponseStatus status400 ("Invalid App Version Specification" :: Text)
+        Just t  -> pure t
     appVersions <- liftIO $ getAvailableAppVersions rootDir ext
     putStrLn $ "valid appversion for " <> (show ext :: String) <> ": " <> show appVersions
     case getSpecifiedAppVersion spec appVersions of

src/Handler/Types/Status.hs

@@ -5,6 +5,8 @@ module Handler.Types.Status where
 import           Startlude
 
 import           Data.Aeson
+import           Data.Char
+import qualified Data.Text          as T
 import           Yesod.Core.Content
 
 import           Lib.Types.Semver
@@ -30,8 +32,8 @@ instance ToContent (Maybe AppVersionRes) where
 instance ToTypedContent (Maybe AppVersionRes) where
     toTypedContent = toTypedContent . toJSON
 
-querySpec :: Maybe Text -> Maybe AppVersionSpecification
-querySpec = (readMaybe . toS =<<)
+-- querySpec :: Text -> Maybe AppVersionSpecification
+-- querySpec = readMaybe . toS . T.filter (not . isSpace)
 
-querySpecD :: AppVersionSpecification -> Maybe Text -> AppVersionSpecification
-querySpecD defaultSpec = fromMaybe defaultSpec . querySpec
+-- querySpecD :: AppVersionSpecification -> Maybe Text -> AppVersionSpecification
+-- querySpecD defaultSpec = fromMaybe defaultSpec . querySpec

src/Handler/Version.hs

@@ -7,7 +7,9 @@ module Handler.Version where
 import           Startlude
 
 import           Control.Monad.Trans.Maybe
+import           Data.Char
 import           Data.String.Interpolate.IsString
+import qualified Data.Text                        as T
 import           Network.HTTP.Types
 import           Yesod.Core
 
@@ -38,7 +40,10 @@ getVersionSysR sysAppId = runMaybeT $ do
 
 getVersionWSpec :: KnownSymbol a => FilePath -> Extension a -> Handler (Maybe AppVersionRes)
 getVersionWSpec rootDir ext = do
-    spec <- querySpecD mostRecentVersion <$> lookupGetParam "spec"
+    specString <- T.filter (not . isSpace) . fromMaybe "*" <$> lookupGetParam "spec"
+    spec <- case readMaybe specString of
+        Nothing -> sendResponseStatus status400 ("Invalid App Version Specification" :: Text)
+        Just t  -> pure t
     appVersions <- liftIO $ getAvailableAppVersions rootDir ext
     let av = version <$> getSpecifiedAppVersion spec appVersions
     pure $ liftA2 AppVersionRes av (pure Nothing)