Add transaction hash utils

4 files changed, 108 insertions, 5 deletions

diff --git a/packages/order-utils/src/eip712_utils.ts b/packages/order-utils/src/eip712_utils.ts
index 646d9e301..4b37dba41 100644
--- a/packages/order-utils/src/eip712_utils.ts
+++ b/packages/order-utils/src/eip712_utils.ts
@@ -11,16 +11,16 @@ export const eip712Utils = {
      * @param   primaryType The primary type found in message
      * @param   types The additional types for the data in message
      * @param   message The contents of the message
-     * @param   exchangeAddress The address of the exchange contract
+     * @param   verifyingContractAddress The address of the verifying contract
      * @return  A typed data object
      */
     createTypedData: (
         primaryType: string,
         types: EIP712Types,
         message: EIP712Object,
-        exchangeAddress: string,
+        verifyingContractAddress: string,
     ): EIP712TypedData => {
-        assert.isETHAddressHex('exchangeAddress', exchangeAddress);
+        assert.isETHAddressHex('verifyingContractAddress', verifyingContractAddress);
         assert.isString('primaryType', primaryType);
         const typedData = {
             types: {
@@ -30,7 +30,7 @@ export const eip712Utils = {
             domain: {
                 name: constants.EIP712_DOMAIN_NAME,
                 version: constants.EIP712_DOMAIN_VERSION,
-                verifyingContract: exchangeAddress,
+                verifyingContract: verifyingContractAddress,
             },
             message,
             primaryType,
@@ -60,7 +60,6 @@ export const eip712Utils = {
      * Creates an ExecuteTransaction EIP712TypedData object for use with signTypedData and
      * 0x Exchange executeTransaction.
      * @param   ZeroExTransaction the 0x transaction
-     * @param   exchangeAddress The address of the exchange contract
      * @return  A typed data object
      */
     createZeroExTransactionTypedData: (zeroExTransaction: ZeroExTransaction): EIP712TypedData => {
diff --git a/packages/order-utils/src/index.ts b/packages/order-utils/src/index.ts
index 2150a02e4..26cbf9665 100644
--- a/packages/order-utils/src/index.ts
+++ b/packages/order-utils/src/index.ts
@@ -3,6 +3,7 @@ export { signatureUtils } from './signature_utils';
 export { generatePseudoRandomSalt } from './salt';
 export { assetDataUtils } from './asset_data_utils';
 export { marketUtils } from './market_utils';
+export { transactionHashUtils } from './transaction_hash';
 export { rateUtils } from './rate_utils';
 export { sortingUtils } from './sorting_utils';
 export { orderParsingUtils } from './parsing_utils';
@@ -51,6 +52,7 @@ export {
     EIP712Object,
     EIP712ObjectValue,
     ZeroExTransaction,
+    SignedZeroExTransaction,
 } from '@0x/types';
 export {
     OrderError,
diff --git a/packages/order-utils/src/transaction_hash.ts b/packages/order-utils/src/transaction_hash.ts
new file mode 100644
index 000000000..2b2345af7
--- /dev/null
+++ b/packages/order-utils/src/transaction_hash.ts
@@ -0,0 +1,46 @@
+import { schemas, SchemaValidator } from '@0x/json-schemas';
+import { SignedZeroExTransaction, ZeroExTransaction } from '@0x/types';
+import { signTypedDataUtils } from '@0x/utils';
+import * as _ from 'lodash';
+
+import { assert } from './assert';
+import { eip712Utils } from './eip712_utils';
+
+export const transactionHashUtils = {
+    /**
+     * Checks if the supplied hex encoded 0x transaction hash is valid.
+     * Note: Valid means it has the expected format, not that a transaction with the transactionHash exists.
+     * Use this method when processing transactionHashes submitted as user input.
+     * @param   transactionHash    Hex encoded transactionHash.
+     * @return  Whether the supplied transactionHash has the expected format.
+     */
+    isValidTransactionHash(transactionHash: string): boolean {
+        // Since this method can be called to check if any arbitrary string conforms to an transactionHash's
+        // format, we only assert that we were indeed passed a string.
+        assert.isString('transactionHash', transactionHash);
+        const schemaValidator = new SchemaValidator();
+        const isValid = schemaValidator.validate(transactionHash, schemas.orderHashSchema).valid;
+        return isValid;
+    },
+    /**
+     * Computes the transactionHash for a supplied 0x transaction.
+     * @param   transaction   An object that conforms to the ZeroExTransaction or SignedZeroExTransaction interface definitions.
+     * @return  Hex encoded string transactionHash from hashing the supplied order.
+     */
+    getTransactionHashHex(transaction: ZeroExTransaction | SignedZeroExTransaction): string {
+        assert.doesConformToSchema('transaction', transaction, schemas.zeroExTransactionSchema, [schemas.hexSchema]);
+        const transactionHashBuff = transactionHashUtils.getTransactionHashBuffer(transaction);
+        const transactionHashHex = `0x${transactionHashBuff.toString('hex')}`;
+        return transactionHashHex;
+    },
+    /**
+     * Computes the transactionHash for a supplied 0x transaction.
+     * @param   transaction   An object that conforms to the ZeroExTransaction or SignedZeroExTransaction interface definitions.
+     * @return  A Buffer containing the resulting transactionHash from hashing the supplied 0x transaction.
+     */
+    getTransactionHashBuffer(transaction: ZeroExTransaction | SignedZeroExTransaction): Buffer {
+        const typedData = eip712Utils.createZeroExTransactionTypedData(transaction);
+        const transactionHashBuff = signTypedDataUtils.generateTypedDataHash(typedData);
+        return transactionHashBuff;
+    },
+};
diff --git a/packages/order-utils/test/transaction_hash_test.ts b/packages/order-utils/test/transaction_hash_test.ts
new file mode 100644
index 000000000..0c371c7c2
--- /dev/null
+++ b/packages/order-utils/test/transaction_hash_test.ts
@@ -0,0 +1,56 @@
+import { ZeroExTransaction } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import * as chai from 'chai';
+import 'mocha';
+
+import { transactionHashUtils } from '../src';
+
+import { constants } from '../src/constants';
+
+import { chaiSetup } from './utils/chai_setup';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+describe.only('0x transaction hashing', () => {
+    describe('#getTransactionHashHex', () => {
+        const expectedTransactionHash = '0x82c9bb2dcac4f868ec7a15c20ff6175cfc384c20ae6a872aa0342a840f108c2b';
+        const fakeVerifyingContractAddress = '0x5e72914535f202659083db3a02c984188fa26e9f';
+        const transaction: ZeroExTransaction = {
+            verifyingContractAddress: fakeVerifyingContractAddress,
+            signerAddress: constants.NULL_ADDRESS,
+            salt: new BigNumber(0),
+            data: constants.NULL_BYTES,
+        };
+        it('calculates the transaction hash', async () => {
+            const transactionHash = transactionHashUtils.getTransactionHashHex(transaction);
+            expect(transactionHash).to.be.equal(expectedTransactionHash);
+        });
+        it('calculates the transaction hash if amounts are strings', async () => {
+            // It's common for developers using javascript to provide the amounts
+            // as strings. Since we eventually toString() the BigNumber
+            // before encoding we should result in the same orderHash in this scenario
+            // tslint:disable-next-line:no-unnecessary-type-assertion
+            const transactionHash = transactionHashUtils.getTransactionHashHex({
+                ...transaction,
+                salt: '0',
+            } as any);
+            expect(transactionHash).to.be.equal(expectedTransactionHash);
+        });
+    });
+    describe('#isValidTransactionHash', () => {
+        it('returns false if the value is not a hex string', () => {
+            const isValid = transactionHashUtils.isValidTransactionHash('not a hex');
+            expect(isValid).to.be.false();
+        });
+        it('returns false if the length is wrong', () => {
+            const isValid = transactionHashUtils.isValidTransactionHash('0xdeadbeef');
+            expect(isValid).to.be.false();
+        });
+        it('returns true if order hash is correct', () => {
+            const orderHashLength = 65;
+            const isValid = transactionHashUtils.isValidTransactionHash(`0x${Array(orderHashLength).join('0')}`);
+            expect(isValid).to.be.true();
+        });
+    });
+});