Display serialised tx endpoint

lib/core-integration/src/Test/Integration/Framework/TestData.hs

@@ -97,7 +97,6 @@ module Test.Integration.Framework.TestData
     , errMsg403TemplateInvalidDuplicateXPub
     , errMsg403TemplateInvalidScript
     , errMsg403InvalidConstructTx
-    , errMsg403transactionAlreadyBalanced
     ) where
 
 import Prelude
@@ -622,10 +621,6 @@ errMsg400ScriptNotUniformRoles :: String
 errMsg400ScriptNotUniformRoles =
     "All keys of a script must have the same role: either payment or delegation."
 
-errMsg403transactionAlreadyBalanced :: String
-errMsg403transactionAlreadyBalanced =
-    "The transaction is already balanced. Please send a transaction that requires more inputs/outputs to be picked to be balanced."
-
 --------------------------------------------------------------------------------
 -- Transaction metadata
 --------------------------------------------------------------------------------

lib/core/src/Cardano/Wallet.hs

@@ -101,9 +101,12 @@ module Cardano.Wallet
     , importRandomAddresses
     , listAddresses
     , normalizeDelegationAddress
+    , lookupTxIns
+    , lookupTxOuts
     , ErrCreateRandomAddress(..)
     , ErrImportRandomAddress(..)
     , ErrImportAddress(..)
+    , ErrDecodeTx (..)
 
     -- ** Payment
     , getTxExpiry
@@ -457,7 +460,7 @@ import Control.Monad.Trans.Except
 import Control.Monad.Trans.Maybe
     ( MaybeT (..), maybeToExceptT )
 import Control.Monad.Trans.State
-    ( runState, state )
+    ( evalState, runState, state )
 import Control.Tracer
     ( Tracer, contramap, traceWith )
 import Crypto.Hash
@@ -559,7 +562,6 @@ import qualified Data.Set as Set
 import qualified Data.Text as T
 import qualified Data.Vector as V
 
-
 -- $Development
 -- __Naming Conventions__
 --
@@ -1169,6 +1171,52 @@ manageRewardBalance _ ctx wid = db & \DBLayer{..} -> do
                                     Address
 -------------------------------------------------------------------------------}
 
+lookupTxIns
+    :: forall ctx s k .
+        ( HasDBLayer IO s k ctx
+        , IsOurs s Address
+        )
+    => ctx
+    -> WalletId
+    -> [TxIn]
+    -> ExceptT ErrDecodeTx IO [(TxIn, Maybe (TxOut, NonEmpty DerivationIndex))]
+lookupTxIns ctx wid txins = db & \DBLayer{..} -> do
+    cp <- mapExceptT atomically
+          $ withExceptT ErrDecodeTxNoSuchWallet
+          $ withNoSuchWallet wid
+          $ readCheckpoint wid
+    pure $ map (\i -> (i, lookupTxIn cp i)) txins
+  where
+    db = ctx ^. dbLayer @IO @s @k
+    lookupTxIn :: Wallet s -> TxIn -> Maybe (TxOut, NonEmpty DerivationIndex)
+    lookupTxIn cp txIn = do
+        out@(TxOut addr _) <- UTxO.lookup txIn (totalUTxO mempty cp)
+        path <- fst $ isOurs addr (getState cp)
+        return (out, path)
+
+lookupTxOuts
+    :: forall ctx s k .
+        ( HasDBLayer IO s k ctx
+        , IsOurs s Address
+        )
+    => ctx
+    -> WalletId
+    -> [TxOut]
+    -> ExceptT ErrDecodeTx IO [(TxOut, Maybe (NonEmpty DerivationIndex))]
+lookupTxOuts ctx wid txouts = db & \DBLayer{..} -> do
+    cp <- mapExceptT atomically
+          $ withExceptT ErrDecodeTxNoSuchWallet
+          $ withNoSuchWallet wid
+          $ readCheckpoint wid
+    -- NOTE: We evolve the state (in practice an address pool) as we loop
+    -- through the outputs, but we don't consider pending transactions.
+    -- /Theoretically/ the outputs might only be discoverable after discovering
+    -- outputs other pending transactions.
+    pure $ flip evalState (getState cp) $ forM txouts $ \out@(TxOut addr _) -> do
+        (out,) <$> state (isOurs addr)
+  where
+    db = ctx ^. dbLayer @IO @s @k
+
 -- | List all addresses of a wallet with their metadata. Addresses
 -- are ordered from the most-recently-discovered to the oldest known.
 listAddresses
@@ -2794,11 +2842,9 @@ data ErrSignPayment
 
 -- | Errors that can occur when balancing transaction.
 data ErrBalanceTx
-    = ErrBalanceTxTxAlreadyBalanced
-    | ErrBalanceTxUpdateError ErrUpdateSealedTx
+    = ErrBalanceTxUpdateError ErrUpdateSealedTx
     | ErrBalanceTxSelectAssets ErrSelectAssets
     | ErrBalanceTxAssignRedeemers ErrAssignRedeemers
-    | ErrBalanceTxNotImplemented
     deriving (Show, Eq)
 
 -- | Errors that can occur when constructing an unsigned transaction.
@@ -2825,6 +2871,11 @@ data ErrWitnessTx
     | ErrWitnessTxIncorrectTTL PastHorizonException
     deriving (Show, Eq)
 
+-- | Errors that can occur when decoding a transaction.
+newtype ErrDecodeTx
+    = ErrDecodeTxNoSuchWallet ErrNoSuchWallet
+    deriving (Show, Eq)
+
 -- | Errors that can occur when submitting a signed transaction to the network.
 data ErrSubmitTx
     = ErrSubmitTxNetwork ErrPostTx

lib/core/src/Cardano/Wallet/Api.hs

@@ -61,6 +61,7 @@ module Cardano.Wallet.Api
         , CreateTransactionOld
         , PostTransactionFeeOld
         , BalanceTransaction
+        , DecodeTransaction
 
     , StakePools
         , ListStakePools
@@ -177,6 +178,7 @@ import Cardano.Wallet.Api.Types
     , ApiCoinSelectionT
     , ApiConstructTransactionDataT
     , ApiConstructTransactionT
+    , ApiDecodedTransactionT
     , ApiFee
     , ApiHealthCheck
     , ApiMaintenanceAction
@@ -528,6 +530,7 @@ type ShelleyTransactions n =
     :<|> CreateTransactionOld n
     :<|> PostTransactionFeeOld n
     :<|> BalanceTransaction n
+    :<|> DecodeTransaction n
 
 -- | https://input-output-hk.github.io/cardano-wallet/api/#operation/constructTransaction
 type ConstructTransaction n = "wallets"
@@ -588,6 +591,13 @@ type BalanceTransaction n = "wallets"
     :> ReqBody '[JSON] (ApiBalanceTransactionPostDataT n)
     :> PostAccepted '[JSON] ApiSerialisedTransaction
 
+-- | https://input-output-hk.github.io/cardano-wallet/api/#operation/decodeTransaction
+type DecodeTransaction n = "wallets"
+    :> Capture "walletId" (ApiT WalletId)
+    :> "transactions-decode"
+    :> ReqBody '[JSON] ApiSerialisedTransaction
+    :> PostAccepted '[JSON] (ApiDecodedTransactionT n)
+
 {-------------------------------------------------------------------------------
                                  Shelley Migrations
 

lib/core/src/Cardano/Wallet/Api/Client.hs

@@ -67,6 +67,7 @@ import Cardano.Wallet.Api.Types
     , ApiCoinSelectionT
     , ApiConstructTransactionDataT
     , ApiConstructTransactionT
+    , ApiDecodedTransactionT
     , ApiFee
     , ApiNetworkClock
     , ApiNetworkInformation (..)
@@ -194,6 +195,10 @@ data TransactionClient = TransactionClient
         :: ApiT WalletId
         -> ApiBalanceTransactionPostDataT Aeson.Value
         -> ClientM ApiSerialisedTransaction
+    , decodeTransaction
+        :: ApiT WalletId
+        -> ApiSerialisedTransaction
+        -> ClientM (ApiDecodedTransactionT Aeson.Value)
     }
 
 data AddressClient = AddressClient
@@ -310,6 +315,7 @@ transactionClient =
             :<|> _postTransaction
             :<|> _postTransactionFee
             :<|> _balanceTransaction
+            :<|> _decodeTransaction
             = client (Proxy @("v2" :> (ShelleyTransactions Aeson.Value)))
 
         _postExternalTransaction
@@ -325,6 +331,7 @@ transactionClient =
             , getTransaction = _getTransaction
             , constructTransaction = _constructTransaction
             , balanceTransaction = _balanceTransaction
+            , decodeTransaction = _decodeTransaction
             }
 
 fromSerialisedTx :: ApiBytesT base SerialisedTx -> ApiT SealedTx
@@ -357,6 +364,7 @@ byronTransactionClient =
         , getTransaction = _getTransaction
         , constructTransaction = _constructTransaction
         , balanceTransaction = error "balance transaction endpoint not supported for byron"
+        , decodeTransaction = error "decode transaction endpoint not supported for byron"
         }
 
 -- | Produces an 'AddressClient n' working against the /wallets API
@@ -458,3 +466,4 @@ type instance PostTransactionOldDataT Aeson.Value = Aeson.Value
 type instance PostTransactionFeeOldDataT Aeson.Value = Aeson.Value
 type instance ApiPutAddressesDataT Aeson.Value = Aeson.Value
 type instance ApiBalanceTransactionPostDataT Aeson.Value = Aeson.Value
+type instance ApiDecodedTransactionT Aeson.Value = Aeson.Value

lib/core/src/Cardano/Wallet/Api/Link.hs

@@ -83,6 +83,7 @@ module Cardano.Wallet.Api.Link
     , createUnsignedTransaction
     , signTransaction
     , balanceTransaction
+    , decodeTransaction
 
       -- * StakePools
     , listStakePools
@@ -681,6 +682,21 @@ balanceTransaction w = discriminate @style
   where
     wid = w ^. typed @(ApiT WalletId)
 
+decodeTransaction
+    :: forall style w.
+        ( HasCallStack
+        , HasType (ApiT WalletId) w
+        , Discriminate style
+        )
+    => w
+    -> (Method, Text)
+decodeTransaction w = discriminate @style
+    (endpoint @(Api.DecodeTransaction Net) (wid &))
+    (notSupported "Byron")
+    (notSupported "Shared")
+  where
+    wid = w ^. typed @(ApiT WalletId)
+
 --
 -- Stake Pools
 --