using throwError

IntersectMBO · Jun 8, 2021 · 5c47477 · 5c47477
1 parent c649140
commit 5c47477
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Showing 2 changed files with 13 additions and 16 deletions.
diff --git a/plutus-pab/src/Plutus/PAB/Db/Beam/ContractStore.hs b/plutus-pab/src/Plutus/PAB/Db/Beam/ContractStore.hs
@@ -72,24 +72,11 @@ mkContracts xs =
 uuidStr :: ContractInstanceId -> Text
 uuidStr = toText . unContractInstanceId
 
-extractState
-  :: Maybe ContractInstance
-  -> State ContractExe
--- TODO: use 'throwError' instead
-extractState Nothing  = error "Couldn't find contract instance"
-extractState (Just c) =
-  fromMaybe (error "No state found for this contract instance")
-            (join (decodeText <$> (_contractInstanceState c)))
-  where
-    decodeText = decode . toLazyByteString . encodeUtf8Builder
-
 handleContractStore ::
   forall effs.
   ( Member DbStoreEffect effs
   , Member (Error PABError) effs
   )
-  -- TODO: State t ~ ContractResponse Value Value Value ContractPABRequest
-  --       instead of 'ContractExe'
   => ContractStore ContractExe
   ~> Eff effs
 handleContractStore = \case
@@ -105,13 +92,21 @@ handleContractStore = \case
             (\ci -> ci ^. contractInstanceState <-. val_ (encode' state))
             (\ci -> ci ^. contractInstanceId ==. val_ (uuidStr instanceId))
 
-  GetState instanceId ->
-    fmap extractState
+  GetState instanceId -> do
+    let decodeText = decode . toLazyByteString . encodeUtf8Builder
+        extractState = \case
+          Nothing -> throwError $ ContractInstanceNotFound instanceId
+          Just  c ->
+            fromMaybe (throwError $ ContractStateNotFound instanceId)
+                      (pure <$> (_contractInstanceState c >>= decodeText))
+
+    join
+      $ fmap extractState
       $ selectOne
       $ select
       $ do
           inst <- all_ (_contractInstances db)
-          guard_ ( inst ^. contractInstanceId ==. val_ (uuidStr instanceId) )
+          guard_ (inst ^. contractInstanceId ==. val_ (uuidStr instanceId))
           pure inst
 
   PutStopInstance instanceId ->

diff --git a/plutus-pab/src/Plutus/PAB/Types.hs b/plutus-pab/src/Plutus/PAB/Types.hs
@@ -52,6 +52,7 @@ data PABError
     | InstanceAlreadyStopped ContractInstanceId -- ^ Attempt to stop the instance failed because it was not running
     | WalletNotFound Wallet
     | MissingConfigFileOption
+    | ContractStateNotFound ContractInstanceId
     deriving stock (Show, Eq, Generic)
     deriving anyclass (ToJSON, FromJSON)
 
@@ -74,6 +75,7 @@ instance Pretty PABError where
         InstanceAlreadyStopped i   -> "Instance already stopped:" <+> pretty i
         WalletNotFound w           -> "Wallet not found:" <+> pretty w
         MissingConfigFileOption    -> "The --config-file option is required"
+        ContractStateNotFound i    -> "State for contract instance not found:" <+> pretty i
 
 data DbConfig =
     DbConfig