king: factor scrying logic into helper lib

Takes care of constructing the full scry path based off the given
components. Fills in timestamp with the current time. Logs errors on
result conversion failures.

pkg/hs/urbit-king/lib/Urbit/King/Scry.hs

@@ -0,0 +1,31 @@
+{-|
+  Scry helpers
+-}
+
+module Urbit.King.Scry (scryNow) where
+
+import Urbit.Prelude
+import Urbit.Vere.Serf.Types
+
+import qualified Urbit.Noun.Time as Time
+
+scryNow :: forall e n
+        . (HasLogFunc e, FromNoun n)
+       => (Time.Wen -> Gang -> Path -> IO (Maybe (Term, Noun)))
+       -> Text
+       -> Ship
+       -> Text
+       -> [Text]
+       -> RIO e (Maybe n)
+scryNow scry vare ship desk path = do
+  env <- ask
+  wen <- io Time.now
+  let wan = tshow $ Time.MkDate wen
+  let pax = Path $ fmap MkKnot $ vare : (tshow ship) : desk : wan : path
+  io (scry wen Nothing pax) >>= \case
+    Just (_, fromNoun @n -> Just v) -> pure $ Just v
+    Just (_, n) -> do
+      logError $ displayShow (vare, "uncanny scry result", pax, n)
+      pure Nothing
+    Nothing -> pure Nothing
+

pkg/hs/urbit-king/lib/Urbit/Vere/Ames.hs

@@ -9,6 +9,7 @@ import Urbit.Prelude
 import Network.Socket              hiding (recvFrom, sendTo)
 import Urbit.Arvo                  hiding (Fake)
 import Urbit.King.Config
+import Urbit.King.Scry
 import Urbit.Vere.Ames.LaneCache
 import Urbit.Vere.Ames.Packet
 import Urbit.Vere.Pier.Types
@@ -341,23 +342,13 @@ ames env who isFake scry enqueueEv stderr = (initialEvents, runAmes)
   scryLane :: HasLogFunc e
            => Ship
            -> RIO e (Maybe [AmesDest])
-  scryLane ship = scry' ["peers", MkKnot $ tshow ship, "forward-lane"]
+  scryLane ship = scry' ["peers", tshow ship, "forward-lane"]
 
   scry' :: forall e n
          . (HasLogFunc e, FromNoun n)
-        => [Knot]
+        => [Text]
         -> RIO e (Maybe n)
-  scry' p = do
-    env <- ask
-    wen <- io Time.now
-    let nkt = MkKnot $ tshow $ Time.MkDate wen
-    let pax = Path $ "ax" : MkKnot (tshow who) : "" : nkt : p
-    io (scry wen Nothing pax) >>= \case
-      Just (_, fromNoun @n -> Just v) -> pure $ Just v
-      Just (_, n) -> do
-        logError $ displayShow ("ames: uncanny scry result", pax, n)
-        pure Nothing
-      Nothing -> pure Nothing
+  scry' = scryNow scry "ax" who ""
 
   ipv4Addr (Jammed (AAVoid v  )) = absurd v
   ipv4Addr (Jammed (AAIpv4 a p)) = SockAddrInet (fromIntegral p) (unIpv4 a)

pkg/hs/urbit-king/lib/Urbit/Vere/Eyre/KingSubsite.hs

@@ -12,6 +12,7 @@ module Urbit.Vere.Eyre.KingSubsite
 import Urbit.Prelude hiding (Builder)
 
 import Data.ByteString.Builder
+import Urbit.King.Scry
 import Urbit.Vere.Serf.Types
 
 import Data.Conduit       (ConduitT, Flush(..), yield)
@@ -100,27 +101,7 @@ kingSubsite who scry func = do  --TODO  unify who into scry
               => Text
               -> RIO e (Maybe Bool)
     scryAuth cookie =
-      scry' $ fmap MkKnot ["authenticated", "cookie", textAsTa cookie]
-
-    --TODO  refactor into scry lib, as:
-    -- (forall n. FromNoun n => Text -> Text -> [Text] -> IO (Maybe n))
-    --                      vanecare -> desk -> restofpath
-    scry' :: forall e n
-           . (HasLogFunc e, FromNoun n)
-          => [Knot]
-          -> RIO e (Maybe n)
-    scry' p = do
-      env <- ask
-      wen <- io Time.now
-      let nkt = MkKnot $ tshow $ Time.MkDate wen
-      let pax = Path $ "ex" : MkKnot (tshow who) : "" : nkt : p
-      putStrLn (tshow pax)
-      io (scry wen Nothing pax) >>= \case
-        Just (_, fromNoun @n -> Just v) -> pure $ Just v
-        Just (_, n) -> do
-          logError $ displayShow ("eyre: uncanny scry result", pax, n)
-          pure Nothing
-        Nothing -> pure Nothing
+      scryNow scry "ex" who "" $ ["authenticated", "cookie", textAsTa cookie]
 
 fourOhFourSubsite :: Ship -> KingSubsite
 fourOhFourSubsite who = KS $ \req respond ->