Small refactor around error responses and more tests (#1282)

* Fix #880, Clean and consolidate error responses
* Fix #1285, Abort on fatal errors
* Add / Detail tests

src/PostgREST/Middleware.hs

@@ -13,7 +13,6 @@ import qualified Data.Aeson                    as JSON
 import qualified Data.HashMap.Strict           as M
 import qualified Hasql.Transaction             as H
 
-import           Network.HTTP.Types.Status     (unauthorized401, status500)
 import           Network.Wai                   (Application, Response)
 import           Network.Wai.Middleware.Cors   (cors)
 import           Network.Wai.Middleware.Gzip   (def, gzip)
@@ -22,7 +21,7 @@ import           Network.Wai.Middleware.Static (only, staticPolicy)
 import           PostgREST.ApiRequest          (ApiRequest(..))
 import           PostgREST.Auth                (JWTAttempt(..))
 import           PostgREST.Config              (AppConfig (..), corsPolicy)
-import           PostgREST.Error               (simpleError)
+import           PostgREST.Error               (errorResponseFor, SimpleError(JwtTokenMissing, JwtTokenInvalid))
 import           PostgREST.QueryBuilder        (unquoted, pgFmtSetLocal, pgFmtSetLocalSearchPath)
 
 import           Protolude
@@ -32,10 +31,10 @@ runWithClaims :: AppConfig -> JWTAttempt ->
                  ApiRequest -> H.Transaction Response
 runWithClaims conf eClaims app req =
   case eClaims of
-    JWTInvalid JWTExpired -> return $ unauthed "JWT expired"
-    JWTInvalid e -> return $ unauthed $ show e
-    JWTMissingSecret -> return $ simpleError status500 [] "Server lacks JWT secret"
-    JWTClaims claims -> do
+    JWTMissingSecret      -> return . errorResponseFor $ JwtTokenMissing
+    JWTInvalid JWTExpired -> return . errorResponseFor . JwtTokenInvalid $ "JWT expired"
+    JWTInvalid e          -> return . errorResponseFor . JwtTokenInvalid . show $ e
+    JWTClaims claims      -> do
       H.sql $ toS . mconcat $ setSearchPathSql : setRoleSql ++ claimsSql ++ headersSql ++ cookiesSql ++ appSettingsSql
       mapM_ H.sql customReqCheck
       app req
@@ -51,14 +50,6 @@ runWithClaims conf eClaims app req =
         claimsWithRole = M.union claims (M.singleton "role" anon)
         anon = JSON.String . toS $ configAnonRole conf
         customReqCheck = (\f -> "select " <> toS f <> "();") <$> configReqCheck conf
-  where
-    unauthed message = simpleError
-      unauthorized401
-      [( "WWW-Authenticate"
-        , "Bearer error=\"invalid_token\", " <>
-          "error_description=" <> show message
-      )]
-      message
 
 defaultMiddle :: Application -> Application
 defaultMiddle =