docs: improve readme

input-output-hk · May 20, 2024 · fba03b7 · fba03b7
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diff --git a/catalyst_voices_packages/catalyst_cardano_serialization/README.md b/catalyst_voices_packages/catalyst_cardano_serialization/README.md
@@ -2,3 +2,170 @@
 
 This package comes with serialization & deserialization of data structures related to Cardano
 blockchain transactions and useful utility functions.
+
+The goal of the package is to generate an unsigned transaction cbor that
+can be signed and submitted to the blockchain. The package communicates neither with the wallet
+nor with the blockchain therefore signing and submission are outside of scope of this package.
+
+## Usage
+
+Import `package:catalyst_cardano_serialization/catalyst_cardano_serialization.dart`,
+instantiate `TransactionBuilder`, provide transaction inputs, outputs, add change address
+for any remaining unspent UTXOs and build the transaction body.
+
+The transaction body must be signed by witnesses in order to be submitted to the blockchain.
+Otherwise the validity of the transaction could not be established and such transaction
+would be rejected. The caller must prove that they are eligible to spend the input UTXOs.
+
+Example:
+
+```dart
+import 'package:catalyst_cardano_serialization/catalyst_cardano_serialization.dart';
+import 'package:cbor/cbor.dart';
+import 'package:convert/convert.dart';
+
+/* cSpell:disable */
+void main() {
+  const txBuilderConfig = TransactionBuilderConfig(
+    feeAlgo: LinearFee(
+      constant: Coin(155381),
+      coefficient: Coin(44),
+    ),
+    maxTxSize: 8000,
+    coinsPerUtxoByte: Coin(4310),
+  );
+
+  final txMetadata = AuxiliaryData(
+    map: {
+      const CborSmallInt(1): CborString('Test'),
+      const CborSmallInt(2): CborBytes(hex.decode('aabbccddeeff')),
+      const CborSmallInt(3): const CborSmallInt(997),
+      const CborSmallInt(4): cbor.decode(
+        hex.decode(
+          '82a50081825820afcf8497561065afe1ca623823508753cc580eb575ac8f1d6cfa'
+          'a18c3ceeac010001818258390080f9e2c88e6c817008f3a812ed889b4a4da8e0bd'
+          '103f86e7335422aa122a946b9ad3d2ddf029d3a828f0468aece76895f15c9efbd6'
+          '9b42771a00df1560021a0002e63003182f075820bdc2b27e6869aa9a5fa23a1f1f'
+          'd3a87025d8703df4fd7b120d058c839dc0415c82a10141aa80',
+        ),
+      ),
+    },
+  );
+
+  final utxo = TransactionUnspentOutput(
+    input: TransactionInput(
+      transactionId: TransactionHash.fromHex(
+        '4c1fbc5433ec764164945d736a09dc087d59ff30e64d26d462ff8570cd4be9a7',
+      ),
+      index: 0,
+    ),
+    output: TransactionOutput(
+      address: ShelleyAddress.fromBech32(
+        'addr_test1qpu5vlrf4xkxv2qpwngf6cjhtw542ayty80v8dyr49rf5ewvxwdrt70'
+        'qlcpeeagscasafhffqsxy36t90ldv06wqrk2qum8x5w',
+      ),
+      amount: const Coin(10162333),
+    ),
+  );
+
+  final txOutput = TransactionOutput(
+    address: ShelleyAddress.fromBech32(
+      'addr_test1vzpwq95z3xyum8vqndgdd9mdnmafh3djcxnc6jemlgdmswcve6tkw',
+    ),
+    amount: const Coin(1000000),
+  );
+
+  final txBuilder = TransactionBuilder(
+    config: txBuilderConfig,
+    inputs: [utxo],
+    // fee can be left empty so that it's auto calculated or can be hardcoded
+    // fee: const Coin(1000000),
+    ttl: const SlotBigNum(410021),
+    auxiliaryData: txMetadata,
+    networkId: NetworkId.testnet,
+  );
+
+  final changeAddress = ShelleyAddress.fromBech32(
+    'addr_test1qrqr2ved9h96x46yazq89yvcgk0r93gwk0shnv06yfrnfryqhpr26'
+    'st0zgxmjnq6gqve99gtzxumclt9mwe5ynq03hjqgkjmhd',
+  );
+
+  final txBody = txBuilder
+      .withOutput(txOutput)
+      .withChangeAddressIfNeeded(changeAddress)
+      // fee can be set manually or left empty to be auto calculated
+      // .withFee(const Coin(10000000))
+      .buildBody();
+
+  final txHash = TransactionHash.fromTransactionBody(txBody);
+  final witnessSet = _signTransaction(txHash);
+
+  final tx = Transaction(
+    body: txBody,
+    isValid: true,
+    witnessSet: witnessSet,
+    auxiliaryData: txMetadata,
+  );
+
+  final txBytes = cbor.encode(tx.toCbor());
+  final txBytesHex = hex.encode(txBytes);
+  print(txBytesHex);
+}
+
+TransactionWitnessSet _signTransaction(TransactionHash txHash) {
+  // return a fake witness set, in real world the wallet
+  // would sign the transaction hash and provide this
+  return TransactionWitnessSet(
+    vkeyWitnesses: {
+      VkeyWitness(
+        vkey: Vkey.fromBytes(
+          hex.decode(
+            '3311ca404fcf22c91d607ace285d70e2'
+            '263a1b81745c39673080329bd1a3f56e',
+          ),
+        ),
+        signature: Ed25519Signature.fromBytes(
+          hex.decode(
+            'f5eb006f048fdfa9b81b0fe3abee1ce1f1a75789d'
+            'c21088b23ebf95c76b050ad157a497999e083e1957'
+            'c2a3d730a07a5b2aef4a755783c9ce778c02c4a08970f',
+          ),
+        ),
+      ),
+    },
+  );
+}
+
+/* cSpell:enable */
+```
+
+
+## Limitations
+
+This package supports a minimal `TransactionBuilder` that does not yet work with
+Smart Contracts, scripts or NFTs. However AuxiliaryMetadata is already supported thus
+it's possible to fulfill some of the use cases.
+
+Only Shelley era bech32 base and stake addresses are supported. Byron era addresses are not supported.
+
+## Supported transaction body fields
+
+| Field | Is supported? |
+| ----- | ------------- |
+| 0 = transaction inputs | ✔️ |
+| 1 = transaction outputs | ✔️ |
+| 2 = transaction fee | ✔️ |
+| 3 = Time to live [TTL] | ✔️ |
+| 4 = certificates | ❌️ |
+| 5 = reward withdrawals | ❌️ |
+| 6 = protocol parameter update | ❌️ |
+| 7 = auxiliary_data_hash | ✔️ |
+| 8 = validity interval start | ❌️ |
+| 9 = mint | ❌️ |
+| 11 = script_data_hash | ❌️ |
+| 13 = collateral inputs | ❌️ |
+| 14 = required signers | ❌️ |
+| 15 = network_id | ✔️ |
+| 16 = collateral return | ❌️ |
+| 17 = total collateral | ❌️ |
+| 18 = reference inputs | ❌️ |