Merge pull request #1243 from IntersectMBO/cardano-wasm-getTxId

cardano-wasm: expose the transaction id (getTxId)

Author: palas

.changes/20260708_120000_cardano-wasm_pablo.lamela_expose_tx_id.yml

@@ -0,0 +1,5 @@
+description: Added `getTxId` to the `cardano-wasm` API (on `UnsignedTx` and `SignedTx`), returning the transaction id (the blake2b-256 hash of the transaction body) as a hex string. The id is available as soon as the transaction body is final and is not affected by signing, so flows that do not submit through the app (e.g. air-gapped signing) can display, copy, or link the id.
+kind:
+- feature
+pr: 1243
+project: cardano-wasm

cardano-wasm/cardano-wasm.cabal

@@ -80,7 +80,7 @@ executable cardano-wasi
   if arch(wasm32)
     ghc-options:
       -no-hs-main
-      "-optl-Wl,--strip-all,--export=hs_init,--export=newTx,--export=newUpcomingEraTx,--export=addTxInput,--export=addSimpleTxOut,--export=appendCertificateToTx,--export=setFee,--export=estimateMinFee,--export=signWithPaymentKey,--export=signWithStakeKey,--export=alsoSignWithPaymentKey,--export=alsoSignWithStakeKey,--export=toCbor,--export=makeStakeAddressStakeDelegationCertificate,--export=makeStakeAddressStakeDelegationCertificateUpcomingEra,--export=makeStakeAddressRegistrationCertificate,--export=makeStakeAddressRegistrationCertificateUpcomingEra,--export=makeStakeAddressUnregistrationCertificate,--export=makeStakeAddressUnregistrationCertificateUpcomingEra,--export=generatePaymentWallet,--export=generateStakeWallet,--export=restorePaymentWalletFromSigningKeyBech32,--export=restoreStakeWalletFromSigningKeyBech32,--export=generateTestnetPaymentWallet,--export=generateTestnetStakeWallet,--export=restoreTestnetPaymentWalletFromSigningKeyBech32,--export=restoreTestnetStakeWalletFromSigningKeyBech32,--export=getAddressBech32,--export=getBech32ForPaymentVerificationKey,--export=getBech32ForPaymentSigningKey,--export=getBech32ForStakeVerificationKey,--export=getBech32ForStakeSigningKey,--export=getBase16ForPaymentVerificationKeyHash,--export=getBase16ForStakeVerificationKeyHash,--export=mallocNBytes,--export=getStrLen,--export=freeMemory"
+      "-optl-Wl,--strip-all,--export=hs_init,--export=newTx,--export=newUpcomingEraTx,--export=addTxInput,--export=addSimpleTxOut,--export=appendCertificateToTx,--export=setFee,--export=estimateMinFee,--export=signWithPaymentKey,--export=signWithStakeKey,--export=getUnsignedTxId,--export=alsoSignWithPaymentKey,--export=alsoSignWithStakeKey,--export=toCbor,--export=getSignedTxId,--export=makeStakeAddressStakeDelegationCertificate,--export=makeStakeAddressStakeDelegationCertificateUpcomingEra,--export=makeStakeAddressRegistrationCertificate,--export=makeStakeAddressRegistrationCertificateUpcomingEra,--export=makeStakeAddressUnregistrationCertificate,--export=makeStakeAddressUnregistrationCertificateUpcomingEra,--export=generatePaymentWallet,--export=generateStakeWallet,--export=restorePaymentWalletFromSigningKeyBech32,--export=restoreStakeWalletFromSigningKeyBech32,--export=generateTestnetPaymentWallet,--export=generateTestnetStakeWallet,--export=restoreTestnetPaymentWalletFromSigningKeyBech32,--export=restoreTestnetStakeWalletFromSigningKeyBech32,--export=getAddressBech32,--export=getBech32ForPaymentVerificationKey,--export=getBech32ForPaymentSigningKey,--export=getBech32ForStakeVerificationKey,--export=getBech32ForStakeSigningKey,--export=getBase16ForPaymentVerificationKeyHash,--export=getBase16ForStakeVerificationKeyHash,--export=mallocNBytes,--export=getStrLen,--export=freeMemory"
   other-modules:
     Cardano.Wasi.Internal.Api.Certificate.StakeCertificate
     Cardano.Wasi.Internal.Api.GRPC

cardano-wasm/js-test/basic-test.golden

@@ -18,6 +18,7 @@
     estimateMinFee: function (protocolParams,numKeyWitnesses,numByronKeyWitnesses,totalRefScriptSize) 
     signWithPaymentKey: function (signingKey) 
     signWithStakeKey: function (signingKey) 
+    getTxId: function () 
   }
 > "Estimated fee:"
 > 164005n
@@ -27,6 +28,7 @@
     alsoSignWithPaymentKey: function (signingKey) 
     alsoSignWithStakeKey: function (signingKey) 
     txToCbor: function () 
+    getTxId: function () 
   }
 > "Tx CBOR:"
 > "84a300d9010281825820be6efd42a3d7b9a00d09d77a5d41e55ceaf0bd093a8aa8a893ce70d9caafd97800018182581d6082935e44937e8b530f32ce672b5d600d0a286b4e8a52c6555f659b871a00989680021a000280a5a100d9010281825820adfc1c30385916da87db1ba3328f0690a57ebb2a6ac9f6f86b2d97f943adae005840a49259b5977aea523b46f01261fbff93e0899e8700319e11f5ab96b67eb628fca1a233ce2d50ee3227b591b84f27237d920d63974d65728362382f751c4d9400f5f6"

cardano-wasm/lib-wrapper/signed-tx.d.ts

@@ -30,6 +30,12 @@ declare interface SignedTx {
      * @returns A promise that resolves to the CBOR representation of the transaction as a hex string.
      */
     txToCbor(): Promise<string>;
+
+    /**
+     * Gets the transaction id (the hash of the transaction body). It is not affected by signing, so it matches the id of the unsigned transaction just before signing.
+     * @returns A promise that resolves to the transaction id as a hex string.
+     */
+    getTxId(): Promise<string>;
 }
 
 export default SignedTx;

cardano-wasm/lib-wrapper/unsigned-tx.d.ts

@@ -66,6 +66,12 @@ declare interface UnsignedTx {
      * @returns A promise that resolves to a `SignedTx` object.
      */
     signWithStakeKey(signingKey: string): Promise<SignedTx>;
+
+    /**
+     * Gets the transaction id (the hash of the transaction body). It can change if the transaction body is modified.
+     * @returns A promise that resolves to the transaction id as a hex string.
+     */
+    getTxId(): Promise<string>;
 }
 
 export default UnsignedTx;

cardano-wasm/npm-wrapper/api.test.js

@@ -46,6 +46,37 @@ describe('Cardano API', () => {
         expect(txCbor).toBe("84a300d9010281825820be6efd42a3d7b9a00d09d77a5d41e55ceaf0bd093a8aa8a893ce70d9caafd97800018182581d6082935e44937e8b530f32ce672b5d600d0a286b4e8a52c6555f659b871a0098968002192710a100d9010281825820adfc1c30385916da87db1ba3328f0690a57ebb2a6ac9f6f86b2d97f943adae0058400b19a00593e659ad0f10951f0f7d1e8a8b93112c60f67277529f91340581639e92ed4d0042ff92a0076cd69deb7e708acfdb73bb4ae79cf4bc06fd6d15efa208f5f6");
     });
 
+    // The transaction id is the blake2b-256 hash of the transaction body, so it
+    // is already available before signing and is not changed by adding witnesses.
+    it('should expose the transaction id on both unsigned and signed transactions', async () => {
+        // Test constants
+        const secretKey = "addr_sk1648253w4tf6fv5fk28dc7crsjsaw7d9ymhztd4favg3cwkhz7x8sl5u3ms";
+        const txInputHash = "be6efd42a3d7b9a00d09d77a5d41e55ceaf0bd093a8aa8a893ce70d9caafd978";
+        const outputAddress = "addr_test1vzpfxhjyjdlgk5c0xt8xw26avqxs52rtf69993j4tajehpcue4v2v";
+
+        // Same transaction as in the simple transaction test above. The expected id
+        // is the blake2b-256 hash of the transaction body bytes in its expected CBOR
+        // (computed independently of this library).
+        const expectedTxId = "4eebc97a1c96eb5537d0ec2172fdb3f0c516dc209d9ab93de585956e0be99ff1";
+
+        const tx = (await api.tx.newTx())
+            .addTxInput(txInputHash, 0)
+            .addSimpleTxOut(outputAddress, 10_000_000n)
+            .setFee(10_000n);
+
+        // The id is available as soon as the body is final (before signing)
+        const unsignedTxId = await tx.getTxId();
+        expect(unsignedTxId).toBe(expectedTxId);
+
+        // Signing does not change the transaction id
+        const signedTx = await tx.signWithPaymentKey(secretKey);
+        expect(await signedTx.getTxId()).toBe(expectedTxId);
+
+        // Nor does adding more witnesses
+        const multiSignedTx = await signedTx.alsoSignWithPaymentKey(secretKey);
+        expect(await multiSignedTx.getTxId()).toBe(expectedTxId);
+    });
+
     // Delegation requires a witness from the stake credential, added with the stake key.
     it('should build a delegation transaction signed with a payment key and a stake key', async () => {
         // Test constants
@@ -80,6 +111,9 @@ describe('Cardano API', () => {
         const txCbor = await signedTx.txToCbor();
 
         expect(txCbor).toBe("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");
+
+        // The transaction id only depends on the body, so the stake witness does not change it
+        expect(await signedTx.getTxId()).toBe(await tx.getTxId());
     });
 
     // The stake key can also be the first signer, with the payment witness added afterwards.

cardano-wasm/src-lib/Cardano/Wasm/Api/Info.hs

@@ -374,6 +374,16 @@ apiInfo =
                     , methodReturnType = NewObject (virtualObjectName signedTxObj)
                     , methodReturnDoc = "A promise that resolves to a `SignedTx` object."
                     }
+              , MethodInfoEntry $
+                  MethodInfo
+                    { methodName = "getUnsignedTxId"
+                    , methodSimpleName = Just "getTxId"
+                    , methodDoc =
+                        "Gets the transaction id (the hash of the transaction body). It can change if the transaction body is modified."
+                    , methodParams = []
+                    , methodReturnType = OtherType TSString
+                    , methodReturnDoc = "A promise that resolves to the transaction id as a hex string."
+                    }
               ]
           }
 
@@ -410,6 +420,16 @@ apiInfo =
                     , methodReturnDoc =
                         "A promise that resolves to the CBOR representation of the transaction as a hex string."
                     }
+              , MethodInfoEntry $
+                  MethodInfo
+                    { methodName = "getSignedTxId"
+                    , methodSimpleName = Just "getTxId"
+                    , methodDoc =
+                        "Gets the transaction id (the hash of the transaction body). It is not affected by signing, so it matches the id of the unsigned transaction just before signing."
+                    , methodParams = []
+                    , methodReturnType = OtherType TSString
+                    , methodReturnDoc = "A promise that resolves to the transaction id as a hex string."
+                    }
               ]
           }
 

cardano-wasm/src-lib/Cardano/Wasm/Api/Tx.hs

@@ -24,6 +24,8 @@ module Cardano.Wasm.Api.Tx
   , alsoSignWithPaymentKeyImpl
   , alsoSignWithStakeKeyImpl
   , toCborImpl
+  , getUnsignedTxIdImpl
+  , getSignedTxIdImpl
   )
 where
 
@@ -49,7 +51,7 @@ import Data.Set qualified as Set
 import Data.Text qualified as Text
 import Data.Text.Encoding qualified as Text
 import GHC.Stack (HasCallStack)
-import Lens.Micro ((%~), (&), (.~), (<>~))
+import Lens.Micro ((%~), (&), (.~), (<>~), (^.))
 
 -- * @UnsignedTx@ object
 
@@ -211,6 +213,16 @@ estimateMinFeeImpl
           numByronKeyWitnesses
           totalRefScriptSize
 
+-- | Get the transaction id of an unsigned transaction object. The transaction
+-- id is the blake2b-256 hash of the transaction body, so it is fully determined
+-- once the body is final and it is not affected by signing.
+getUnsignedTxIdImpl :: UnsignedTxObject -> String
+getUnsignedTxIdImpl (UnsignedTxObject era (Exp.UnsignedTx tx)) =
+  obtainCommonConstraints era $
+    Text.unpack $
+      Api.serialiseToRawBytesHexText $
+        TxBody.getTxIdShelley (Api.convert era) (tx ^. Ledger.bodyTxL)
+
 -- * @SignedTx@ object
 
 -- | An object representing a signed transaction.
@@ -272,3 +284,13 @@ toCborImpl (SignedTxObject era signedTx) =
   obtainCommonConstraints era $
     Text.unpack $
       Text.decodeUtf8 (Api.serialiseToRawBytesHex signedTx)
+
+-- | Get the transaction id of a signed transaction object. The transaction
+-- id is the blake2b-256 hash of the transaction body, so it is not affected
+-- by signing and it matches the id of the unsigned transaction.
+getSignedTxIdImpl :: SignedTxObject -> String
+getSignedTxIdImpl (SignedTxObject era (Exp.SignedTx tx)) =
+  obtainCommonConstraints era $
+    Text.unpack $
+      Api.serialiseToRawBytesHexText $
+        TxBody.getTxIdShelley (Api.convert era) (tx ^. Ledger.bodyTxL)

cardano-wasm/src-wasi/Cardano/Wasi/Internal/Api/Tx.hs

@@ -13,6 +13,8 @@ module Cardano.Wasi.Internal.Api.Tx
   , alsoSignWithPaymentKey
   , alsoSignWithStakeKey
   , toCbor
+  , getUnsignedTxId
+  , getSignedTxId
   )
 where
 
@@ -64,6 +66,9 @@ foreign export ccall "signWithPaymentKey"
 foreign export ccall "signWithStakeKey"
   signWithStakeKey :: UnsignedTxObjectJSON -> CString -> IO SignedTxObjectJSON
 
+foreign export ccall "getUnsignedTxId"
+  getUnsignedTxId :: UnsignedTxObjectJSON -> IO CString
+
 #endif
 
 type UnsignedTxObjectJSON = CString
@@ -138,6 +143,11 @@ signWithStakeKey unsignedTxObject signingKeyBech32 =
             <*> stringToSigningKey signingKeyBech32
         )
 
+getUnsignedTxId :: UnsignedTxObjectJSON -> IO CString
+getUnsignedTxId unsignedTxObject =
+  newCString . getUnsignedTxIdImpl
+    =<< fromCJSON False "UnsignedTx" unsignedTxObject
+
 -- * SignedTxObject
 
 #if defined(wasm32_HOST_ARCH)
@@ -151,6 +161,9 @@ foreign export ccall "alsoSignWithStakeKey"
 foreign export ccall "toCbor"
   toCbor :: SignedTxObjectJSON -> IO CString
 
+foreign export ccall "getSignedTxId"
+  getSignedTxId :: SignedTxObjectJSON -> IO CString
+
 #endif
 
 type SignedTxObjectJSON = CString
@@ -175,3 +188,8 @@ toCbor :: SignedTxObjectJSON -> IO CString
 toCbor signedTxObject =
   newCString . toCborImpl
     =<< fromCJSON False "SignedTx" signedTxObject
+
+getSignedTxId :: SignedTxObjectJSON -> IO CString
+getSignedTxId signedTxObject =
+  newCString . getSignedTxIdImpl
+    =<< fromCJSON False "SignedTx" signedTxObject

cardano-wasm/src-wasm/Cardano/Wasm/Internal/JavaScript/Bridge.hs

@@ -390,6 +390,9 @@ foreign export javascript "signWithPaymentKey"
 foreign export javascript "signWithStakeKey"
   signWithStakeKey :: JSUnsignedTx -> JSSigningKey -> IO JSSignedTx
 
+foreign export javascript "getUnsignedTxId"
+  getUnsignedTxId :: JSUnsignedTx -> IO JSString
+
 -- | Create a new unsigned transaction in the current era.
 newTx :: HasCallStack => IO JSUnsignedTx
 newTx = toJSVal Wasm.newTxImpl
@@ -528,6 +531,11 @@ signWithStakeKey jsUnsignedTx jsSigningKey =
             <*> fromJSVal jsSigningKey
         )
 
+-- | Get the transaction id (the hash of the transaction body) of an unsigned transaction.
+getUnsignedTxId :: HasCallStack => JSUnsignedTx -> IO JSString
+getUnsignedTxId jsUnsignedTx =
+  toJSVal . Wasm.getUnsignedTxIdImpl =<< fromJSVal jsUnsignedTx
+
 -- * SignedTxObject
 
 foreign export javascript "alsoSignWithPaymentKey"
@@ -539,6 +547,9 @@ foreign export javascript "alsoSignWithStakeKey"
 foreign export javascript "txToCbor"
   txToCbor :: JSSignedTx -> IO JSString
 
+foreign export javascript "getSignedTxId"
+  getSignedTxId :: JSSignedTx -> IO JSString
+
 -- | Sign an unsigned transaction with a payment key.
 alsoSignWithPaymentKey :: HasCallStack => JSSignedTx -> JSSigningKey -> IO JSSignedTx
 alsoSignWithPaymentKey jsSignedTx jsSigningKey =
@@ -562,6 +573,11 @@ txToCbor :: HasCallStack => JSSignedTx -> IO JSString
 txToCbor jsSignedTx =
   toJSVal . Wasm.toCborImpl =<< fromJSVal jsSignedTx
 
+-- | Get the transaction id (the hash of the transaction body) of a signed transaction.
+getSignedTxId :: HasCallStack => JSSignedTx -> IO JSString
+getSignedTxId jsSignedTx =
+  toJSVal . Wasm.getSignedTxIdImpl =<< fromJSVal jsSignedTx
+
 -- * GrpcObject
 
 foreign export javascript "newGrpcConnection"