flip args to inTransaction

src/Main.hs

@@ -41,8 +41,8 @@ main = do
 
   Prelude.putStrLn $ "Listening on port " ++ (show $ configPort conf :: String)
   conn <- connectPostgreSQL' dburi
-  runTLS tls settings $ gzip def $ cors corsPolicy $
-    inTransaction conn (app (cs $ configAnonRole conf))
+  runTLS tls settings . gzip def . cors corsPolicy $
+    inTransaction (app (cs $ configAnonRole conf)) conn
 
   where
     describe = progDesc "create a REST API to an existing Postgres database"

src/Middleware.hs

@@ -10,14 +10,13 @@ import Database.HDBC.PostgreSQL (Connection)
 import Network.HTTP.Types.Header (hContentType)
 import Network.HTTP.Types.Status (status400)
 import Database.HDBC.Types (SqlError(..))
-import Network.Wai (Application, Request, Response, ResponseReceived, responseLBS)
+import Network.Wai (Application, responseLBS)
 import Control.Exception (finally, catchJust)
 
-type ResHandler = Response -> IO ResponseReceived
 
-inTransaction :: Connection -> (Connection -> Application) -> Request -> ResHandler -> IO ResponseReceived
-inTransaction conn app req respond =
-  finally (putStrLn "begin txn" >> runRaw conn "begin" >> app conn req respond) (putStrLn "commit txn" >> runRaw conn "commit")
+inTransaction :: (Connection -> Application) -> (Connection -> Application)
+inTransaction app conn req respond =
+  finally (runRaw conn "begin" >> app conn req respond) (runRaw conn "commit")
 
 instance ToJSON SqlError where
   toJSON t = object [
@@ -28,7 +27,7 @@ instance ToJSON SqlError where
       ]
     ]
 
-reportPgErrors :: Application -> Request -> ResHandler -> IO ResponseReceived
+reportPgErrors :: Application -> Application
 reportPgErrors app req respond =
   catchJust isPgException (app req respond) (
       respond . responseLBS status400 [(hContentType, "application/json")]