refactor transport encoding, make client IO error "temporary" (#634)

* file server/client framework

* refactor

* make IOError temporary

* fix test

src/Simplex/Messaging/Client.hs

@@ -62,7 +62,9 @@ module Simplex.Messaging.Client
     defaultNetworkConfig,
     transportClientConfig,
     chooseTransportHost,
+    proxyUsername,
     ServerTransmission,
+    ClientCommand,
   )
 where
 
@@ -317,9 +319,6 @@ getProtocolClient transportSession@(_, srv, _) cfg@ProtocolClientConfig {qSize,
         Just (Left e) -> Left e
         Nothing -> Left PCENetworkError
 
-    proxyUsername :: TransportSession msg -> ByteString
-    proxyUsername (userId, _, entityId_) = C.sha256Hash $ bshow userId <> maybe "" (":" <>) entityId_
-
     useTransport :: (ServiceName, ATransport)
     useTransport = case port srv of
       "" -> defaultTransport cfg
@@ -382,6 +381,9 @@ getProtocolClient transportSession@(_, srv, _) cfg@ProtocolClientConfig {qSize,
           Right msg -> atomically $ mapM_ (`writeTBQueue` serverTransmission c qId msg) msgQ
           Left e -> putStrLn $ "SMP client error: " <> show e
 
+proxyUsername :: TransportSession msg -> ByteString
+proxyUsername (userId, _, entityId_) = C.sha256Hash $ bshow userId <> maybe "" (":" <>) entityId_
+
 -- | Disconnects client from the server and terminates client threads.
 closeProtocolClient :: ProtocolClient msg -> IO ()
 closeProtocolClient = mapM_ uninterruptibleCancel . action