feat: added a unique identifier to the quote within the timestamp met…

…adata … (#281)

* Added a unique identifier to the quote within the timestamp metadata field

* Added unit test for affiliate data generation, other nits

* prettier 🤦

src/constants.ts

@@ -18,6 +18,7 @@ export const ONE_SECOND_MS = 1000;
 export const ONE_MINUTE_MS = ONE_SECOND_MS * 60;
 export const TEN_MINUTES_MS = ONE_MINUTE_MS * 10;
 export const DEFAULT_VALIDATION_GAS_LIMIT = 10e6;
+export const HEX_BASE = 16;
 
 // The number of orders to post to Mesh at one time
 export const MESH_ORDERS_BATCH_SIZE = 200;

src/utils/number_utils.ts

@@ -0,0 +1,19 @@
+export const numberUtils = {
+    // from MDN https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random
+    randomNumberInclusive: (minimumSpecified: number, maximumSpecified: number): number => {
+        const min = Math.ceil(minimumSpecified);
+        const max = Math.floor(maximumSpecified);
+        return Math.floor(Math.random() * (max - min + 1)) + min; // The maximum is inclusive and the minimum is inclusive
+    },
+    // creates a random hex number of desired length by stringing together
+    // random integers from 1-15, guaranteeing the
+    // result is a hex number of the given length
+    randomHexNumberOfLength: (numberLength: number): string => {
+        let res = '';
+        for (let i = 0; i < numberLength; i++) {
+            // tslint:disable-next-line:custom-no-magic-numbers
+            res = `${res}${numberUtils.randomNumberInclusive(1, 15).toString(16)}`;
+        }
+        return res;
+    },
+};

src/utils/service_utils.ts

@@ -18,6 +18,7 @@ import {
     GAS_BURN_REFUND,
     GST_DIVISOR,
     GST_INTERACTION_COST,
+    HEX_BASE,
     ONE_SECOND_MS,
     PERCENTAGE_SIG_DIGITS,
     SSTORE_COST,
@@ -29,6 +30,8 @@ import { GasTokenRefundInfo, GetSwapQuoteResponseLiquiditySource } from '../type
 import { orderUtils } from '../utils/order_utils';
 import { findTokenDecimalsIfExists } from '../utils/token_metadata_utils';
 
+import { numberUtils } from './number_utils';
+
 export const serviceUtils = {
     attributeSwapQuoteOrders(
         swapQuote: MarketSellSwapQuote | MarketBuySwapQuote,
@@ -69,8 +72,20 @@ export const serviceUtils = {
             stateMutability: 'view',
             type: 'function',
         });
-        const timestamp = new BigNumber(Date.now() / ONE_SECOND_MS).integerValue();
-        const encodedAffiliateData = affiliateCallDataEncoder.encode([affiliateAddressOrDefault, timestamp]);
+
+        // Generate unique identiifer
+        const timestampInSeconds = new BigNumber(Date.now() / ONE_SECOND_MS).integerValue();
+        const hexTimestamp = timestampInSeconds.toString(HEX_BASE);
+        const randomNumber = numberUtils.randomHexNumberOfLength(10);
+
+        // Concatenate the hex identifier with the hex timestamp
+        // In the final encoded call data, this will leave us with a 5-byte ID followed by
+        // a 4-byte timestamp, and won't break parsers of the timestamp made prior to the
+        // addition of the ID
+        const uniqueIdentifier = new BigNumber(`${randomNumber}${hexTimestamp}`, HEX_BASE);
+
+        // Encode additional call data and return
+        const encodedAffiliateData = affiliateCallDataEncoder.encode([affiliateAddressOrDefault, uniqueIdentifier]);
         const affiliatedData = `${data}${encodedAffiliateData.slice(2)}`;
         return affiliatedData;
     },

test/constants.ts

@@ -18,3 +18,4 @@ export const SYMBOL_TO_ADDRESS: ObjectMap<string> = {
     ZRX: ZRX_TOKEN_ADDRESS,
     WETH: WETH_TOKEN_ADDRESS,
 };
+export const AFFILIATE_DATA_SELECTOR = '869584cd';

test/service_utils_test.ts

@@ -6,7 +6,7 @@ import 'mocha';
 import { ZERO } from '../src/constants';
 import { serviceUtils } from '../src/utils/service_utils';
 
-import { MAX_INT } from './constants';
+import { AFFILIATE_DATA_SELECTOR, MAX_INT } from './constants';
 
 const SUITE_NAME = 'serviceUtils test';
 
@@ -68,4 +68,26 @@ describe(SUITE_NAME, () => {
             expect(gasTokenGasCost.toNumber()).to.be.eq(0);
         });
     });
+    describe('attributeCallData', () => {
+        it('it returns a reasonable ID and timestamp', () => {
+            const fakeCallData = '0x0000000000000';
+            const fakeAffiliate = '0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee';
+            const attributedCallData = serviceUtils.attributeCallData(fakeCallData, fakeAffiliate);
+            const currentTime = new Date();
+
+            // parse out items from call data to ensure they are reasonable values
+            const selectorPos = attributedCallData.indexOf(AFFILIATE_DATA_SELECTOR);
+            const affiliateAddress = '0x'.concat(attributedCallData.substring(selectorPos + 32, selectorPos + 72));
+            const randomId = attributedCallData.substring(selectorPos + 118, selectorPos + 128);
+            const timestampFromCallDataHex = attributedCallData.substring(selectorPos + 128, selectorPos + 136);
+            const timestampFromCallData = parseInt(timestampFromCallDataHex, 16);
+
+            expect(affiliateAddress).to.be.eq(fakeAffiliate);
+            // call data timestamp is within 3 seconds of timestamp created during test
+            expect(timestampFromCallData).to.be.greaterThan(currentTime.getTime() / 1000 - 3);
+            expect(timestampFromCallData).to.be.lessThan(currentTime.getTime() / 1000 + 3);
+            // ID is a 10-digit hex number
+            expect(randomId).to.match(/[0-9A-Fa-f]{10}/);
+        });
+    });
 });