Publish

- @0x/asset-swapper@16.65.0

packages/asset-swapper/CHANGELOG.json

@@ -1,4 +1,14 @@
 [
+    {
+        "version": "16.65.0",
+        "changes": [
+            {
+                "note": "Use 0x gas api instead of eth gas station api",
+                "pr": 532
+            }
+        ],
+        "timestamp": 1659391840
+    },
     {
         "version": "16.64.0",
         "changes": [

packages/asset-swapper/CHANGELOG.md

@@ -5,6 +5,10 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v16.65.0 - _August 1, 2022_
+
+    * Use 0x gas api instead of eth gas station api (#532)
+
 ## v16.64.0 - _July 27, 2022_
 
     * Refactor `TokenAdjacency` and `TokenAdjacencyBuilder` (#517)

packages/asset-swapper/docs/reference.mdx

@@ -1897,7 +1897,7 @@ ___
 
 # Interface: SwapQuoteRequestOpts
 
-slippagePercentage: The percentage buffer to add to account for slippage. Affects max ETH price estimates. Defaults to 0.2 (20%).
+slippagePercentage: The percentage buffer to add to account for slippage. Affects max ETH price estimates. Defaults to 0.01 (1%).
 gasPrice: gas price to determine protocolFee amount, default to ethGasStation fast amount
 
 

packages/asset-swapper/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/asset-swapper",
-    "version": "16.64.0",
+    "version": "16.65.0",
     "engines": {
         "node": ">=6.12"
     },
@@ -109,6 +109,7 @@
         "dirty-chai": "^2.0.1",
         "gitpkg": "https://github.com/0xProject/gitpkg.git",
         "mocha": "^6.2.0",
+        "msw": "^0.44.2",
         "npm-run-all": "^4.1.2",
         "nyc": "^11.0.1",
         "shx": "^0.2.2",

packages/asset-swapper/src/constants.ts

@@ -19,7 +19,7 @@ import {
     DEFAULT_TOKEN_ADJACENCY_GRAPH_BY_CHAIN_ID,
 } from './utils/market_operation_utils/constants';
 
-const ETH_GAS_STATION_API_URL = 'https://ethgasstation.info/api/ethgasAPI.json';
+const ZERO_EX_GAS_API_URL = 'https://gas.api.0x.org/source/median';
 const NULL_BYTES = '0x';
 const NULL_ERC20_ASSET_DATA = '0xf47261b00000000000000000000000000000000000000000000000000000000000000000';
 const NULL_ADDRESS = '0x0000000000000000000000000000000000000000';
@@ -48,7 +48,7 @@ const DEFAULT_SWAP_QUOTER_OPTS: SwapQuoterOpts = {
     orderRefreshIntervalMs: 10000, // 10 seconds
     ...DEFAULT_ORDER_PRUNER_OPTS,
     samplerGasLimit: 500e6,
-    ethGasStationUrl: ETH_GAS_STATION_API_URL,
+    zeroExGasApiUrl: ZERO_EX_GAS_API_URL,
     rfqt: {
         integratorsWhitelist: [],
         makerAssetOfferings: {},
@@ -99,7 +99,7 @@ export const POSITIVE_SLIPPAGE_FEE_TRANSFORMER_GAS = new BigNumber(30000);
 export const KEEP_ALIVE_TTL = 5 * 60 * ONE_SECOND_MS;
 
 export const constants = {
-    ETH_GAS_STATION_API_URL,
+    ZERO_EX_GAS_API_URL,
     PROTOCOL_FEE_MULTIPLIER,
     POSITIVE_SLIPPAGE_FEE_TRANSFORMER_GAS,
     NULL_BYTES,

packages/asset-swapper/src/index.ts

@@ -157,8 +157,6 @@ export {
     GetMarketOrdersRfqOpts,
     LiquidityProviderFillData,
     LiquidityProviderRegistry,
-    MarketDepth,
-    MarketDepthSide,
     MooniswapFillData,
     MultiHopFillData,
     NativeRfqOrderFillData,

packages/asset-swapper/src/swap_quoter.ts

@@ -36,9 +36,6 @@ import {
     FillData,
     GasSchedule,
     GetMarketOrdersOpts,
-    MarketDepth,
-    MarketDepthSide,
-    MarketSideLiquidity,
     OptimizedMarketOrder,
     OptimizerResultWithReport,
 } from './utils/market_operation_utils/types';
@@ -112,7 +109,7 @@ export class SwapQuoter {
         };
         this._protocolFeeUtils = ProtocolFeeUtils.getInstance(
             constants.PROTOCOL_FEE_UTILS_POLLING_INTERVAL_IN_MS,
-            options.ethGasStationUrl,
+            options.zeroExGasApiUrl,
         );
         // Allow the sampler bytecode to be overwritten using geths override functionality
         const samplerBytecode = _.get(artifacts.ERC20BridgeSampler, 'compilerOutput.evm.deployedBytecode.object');
@@ -228,67 +225,6 @@ export class SwapQuoter {
         return batchSwapQuotes.filter(x => x !== undefined) as MarketBuySwapQuote[];
     }
 
-    /**
-     * Returns the bids and asks liquidity for the entire market.
-     * For certain sources (like AMM's) it is recommended to provide a practical maximum takerAssetAmount.
-     * @param   makerTokenAddress The address of the maker asset
-     * @param   takerTokenAddress The address of the taker asset
-     * @param   takerAssetAmount  The amount to sell and buy for the bids and asks.
-     *
-     * @return  An object that conforms to MarketDepth that contains all of the samples and liquidity
-     *          information for the source.
-     */
-    public async getBidAskLiquidityForMakerTakerAssetPairAsync(
-        makerToken: string,
-        takerToken: string,
-        takerAssetAmount: BigNumber,
-        options: Partial<SwapQuoteRequestOpts> = {},
-    ): Promise<MarketDepth> {
-        assert.isString('makerToken', makerToken);
-        assert.isString('takerToken', takerToken);
-        const sourceFilters = new SourceFilters([], options.excludedSources, options.includedSources);
-
-        let [sellOrders, buyOrders] = !sourceFilters.isAllowed(ERC20BridgeSource.Native)
-            ? [[], []]
-            : await Promise.all([
-                  this.orderbook.getOrdersAsync(makerToken, takerToken),
-                  this.orderbook.getOrdersAsync(takerToken, makerToken),
-              ]);
-        if (!sellOrders || sellOrders.length === 0) {
-            sellOrders = [createDummyOrder(makerToken, takerToken)];
-        }
-        if (!buyOrders || buyOrders.length === 0) {
-            buyOrders = [createDummyOrder(takerToken, makerToken)];
-        }
-
-        const getMarketDepthSide = (marketSideLiquidity: MarketSideLiquidity): MarketDepthSide => {
-            const { dexQuotes, nativeOrders } = marketSideLiquidity.quotes;
-            const { side } = marketSideLiquidity;
-
-            return [
-                ...dexQuotes,
-                nativeOrders.map(o => {
-                    return {
-                        input: side === MarketOperation.Sell ? o.fillableTakerAmount : o.fillableMakerAmount,
-                        output: side === MarketOperation.Sell ? o.fillableMakerAmount : o.fillableTakerAmount,
-                        fillData: o,
-                        source: ERC20BridgeSource.Native,
-                    };
-                }),
-            ];
-        };
-        const [bids, asks] = await Promise.all([
-            this._marketOperationUtils.getMarketBuyLiquidityAsync(buyOrders, takerAssetAmount, options),
-            this._marketOperationUtils.getMarketSellLiquidityAsync(sellOrders, takerAssetAmount, options),
-        ]);
-        return {
-            bids: getMarketDepthSide(bids),
-            asks: getMarketDepthSide(asks),
-            makerTokenDecimals: asks.makerTokenDecimals,
-            takerTokenDecimals: asks.takerTokenDecimals,
-        };
-    }
-
     /**
      * Returns the recommended gas price for a fast transaction
      */

packages/asset-swapper/src/types.ts

@@ -337,7 +337,7 @@ export interface SwapQuoterOpts extends OrderPrunerOpts {
     contractAddresses?: AssetSwapperContractAddresses;
     samplerGasLimit?: number;
     multiBridgeAddress?: string;
-    ethGasStationUrl?: string;
+    zeroExGasApiUrl?: string;
     rfqt?: SwapQuoterRfqOpts;
     samplerOverrides?: SamplerOverrides;
     tokenAdjacencyGraph?: TokenAdjacencyGraph;

packages/asset-swapper/src/utils/market_operation_utils/constants.ts

@@ -2176,7 +2176,6 @@ export const LIDO_INFO_BY_CHAIN = valueByChainId<LidoInfo>(
     },
 );
 
-export const BALANCER_SUBGRAPH_URL = 'https://api.thegraph.com/subgraphs/name/balancer-labs/balancer';
 export const BALANCER_TOP_POOLS_FETCHED = 250;
 export const BALANCER_MAX_POOLS_FETCHED = 3;
 

packages/asset-swapper/src/utils/market_operation_utils/index.ts

@@ -862,14 +862,9 @@ export class MarketOperationUtils {
     }
 
     private async _refreshPoolCacheIfRequiredAsync(takerToken: string, makerToken: string): Promise<void> {
-        void Promise.all(
-            Object.values(this._sampler.poolsCaches).map(async cache => {
-                if (!cache || cache.isFresh(takerToken, makerToken)) {
-                    return Promise.resolve([]);
-                }
-                return cache.getFreshPoolsForPairAsync(takerToken, makerToken);
-            }),
-        );
+        _.values(this._sampler.poolsCaches)
+            .filter(cache => cache !== undefined && !cache.isFresh(takerToken, makerToken))
+            .forEach(cache => cache?.getFreshPoolsForPairAsync(takerToken, makerToken));
     }
 }
 

packages/asset-swapper/src/utils/market_operation_utils/pools_cache/balancer_utils.ts

@@ -1,16 +1,21 @@
+import { ChainId } from '@0x/contract-addresses';
 import { getPoolsWithTokens, parsePoolData } from 'balancer-labs-sor-v1';
 import { Pool } from 'balancer-labs-sor-v1/dist/types';
 import { gql, request } from 'graphql-request';
 
 import { DEFAULT_WARNING_LOGGER } from '../../../constants';
 import { LogFunction } from '../../../types';
-import { BALANCER_MAX_POOLS_FETCHED, BALANCER_SUBGRAPH_URL, BALANCER_TOP_POOLS_FETCHED } from '../constants';
+import { BALANCER_MAX_POOLS_FETCHED, BALANCER_TOP_POOLS_FETCHED } from '../constants';
 
-import { CacheValue, PoolsCache } from './pools_cache';
+import { NoOpPoolsCache } from './no_op_pools_cache';
+import { AbstractPoolsCache, CacheValue, PoolsCache } from './pools_cache';
 
 // tslint:disable:custom-no-magic-numbers
 const ONE_DAY_MS = 24 * 60 * 60 * 1000;
 // tslint:enable:custom-no-magic-numbers
+// tslint:disable: member-ordering
+
+const BALANCER_SUBGRAPH_URL = 'https://api.thegraph.com/subgraphs/name/balancer-labs/balancer';
 
 interface BalancerPoolResponse {
     id: string;
@@ -20,10 +25,18 @@ interface BalancerPoolResponse {
     totalWeight: string;
 }
 
-export class BalancerPoolsCache extends PoolsCache {
-    constructor(
+export class BalancerPoolsCache extends AbstractPoolsCache {
+    public static create(chainId: ChainId): PoolsCache {
+        if (chainId !== ChainId.Mainnet) {
+            return new NoOpPoolsCache();
+        }
+
+        return new BalancerPoolsCache();
+    }
+
+    private constructor(
         private readonly _subgraphUrl: string = BALANCER_SUBGRAPH_URL,
-        cache: { [key: string]: CacheValue } = {},
+        cache: Map<string, CacheValue> = new Map(),
         private readonly maxPoolsFetched: number = BALANCER_MAX_POOLS_FETCHED,
         private readonly _topPoolsFetched: number = BALANCER_TOP_POOLS_FETCHED,
         private readonly _warningLogger: LogFunction = DEFAULT_WARNING_LOGGER,

packages/asset-swapper/src/utils/market_operation_utils/pools_cache/balancer_v2_utils.ts

@@ -9,7 +9,10 @@ import { LogFunction } from '../../../types';
 import { BALANCER_MAX_POOLS_FETCHED, BALANCER_TOP_POOLS_FETCHED } from '../constants';
 
 import { parsePoolData } from './balancer_sor_v2';
-import { CacheValue, PoolsCache } from './pools_cache';
+import { NoOpPoolsCache } from './no_op_pools_cache';
+import { AbstractPoolsCache, CacheValue, PoolsCache } from './pools_cache';
+
+// tslint:disable: member-ordering
 
 const BEETHOVEN_X_SUBGRAPH_URL_BY_CHAIN = new Map<ChainId, string>([
     [ChainId.Fantom, 'https://api.thegraph.com/subgraphs/name/beethovenxfi/beethovenx'],
@@ -28,11 +31,11 @@ interface BalancerPoolResponse {
     amp: string | null;
 }
 
-export class BalancerV2PoolsCache extends PoolsCache {
-    public static createBeethovenXPoolCache(chainId: ChainId): BalancerV2PoolsCache | undefined {
+export class BalancerV2PoolsCache extends AbstractPoolsCache {
+    public static createBeethovenXPoolCache(chainId: ChainId): PoolsCache {
         const subgraphUrl = BEETHOVEN_X_SUBGRAPH_URL_BY_CHAIN.get(chainId);
         if (subgraphUrl === undefined) {
-            return undefined;
+            return new NoOpPoolsCache();
         }
 
         return new BalancerV2PoolsCache(subgraphUrl);
@@ -58,12 +61,12 @@ export class BalancerV2PoolsCache extends PoolsCache {
         };
     }
 
-    constructor(
+    private constructor(
         private readonly subgraphUrl: string,
         private readonly maxPoolsFetched: number = BALANCER_MAX_POOLS_FETCHED,
         private readonly _topPoolsFetched: number = BALANCER_TOP_POOLS_FETCHED,
         private readonly _warningLogger: LogFunction = DEFAULT_WARNING_LOGGER,
-        cache: { [key: string]: CacheValue } = {},
+        cache: Map<string, CacheValue> = new Map(),
     ) {
         super(cache);
         void this._loadTopPoolsAsync();

packages/asset-swapper/src/utils/market_operation_utils/pools_cache/cream_utils.ts

@@ -1,18 +1,20 @@
+import { ChainId } from '@0x/contract-addresses';
 import { Pool } from 'balancer-labs-sor-v1/dist/types';
 import { getPoolsWithTokens, parsePoolData } from 'cream-sor';
 
 import { BALANCER_MAX_POOLS_FETCHED } from '../constants';
 
-import { CacheValue, PoolsCache } from './pools_cache';
+import { NoOpPoolsCache } from './no_op_pools_cache';
+import { AbstractPoolsCache, CacheValue, PoolsCache } from './pools_cache';
 
-export class CreamPoolsCache extends PoolsCache {
-    constructor(
-        _cache: { [key: string]: CacheValue } = {},
-        private readonly maxPoolsFetched: number = BALANCER_MAX_POOLS_FETCHED,
-    ) {
-        super(_cache);
+export class CreamPoolsCache extends AbstractPoolsCache {
+    public static create(chainId: ChainId): PoolsCache {
+        if (chainId !== ChainId.Mainnet) {
+            return new NoOpPoolsCache();
+        }
+
+        return new CreamPoolsCache();
     }
-
     protected async _fetchPoolsForPairAsync(takerToken: string, makerToken: string): Promise<Pool[]> {
         try {
             const poolData = (await getPoolsWithTokens(takerToken, makerToken)).pools;
@@ -25,4 +27,10 @@ export class CreamPoolsCache extends PoolsCache {
             return [];
         }
     }
+    private constructor(
+        _cache: Map<string, CacheValue> = new Map(),
+        private readonly maxPoolsFetched: number = BALANCER_MAX_POOLS_FETCHED,
+    ) {
+        super(_cache);
+    }
 }

packages/asset-swapper/src/utils/market_operation_utils/pools_cache/index.ts

@@ -1,4 +1,4 @@
 export { BalancerPoolsCache } from './balancer_utils';
 export { BalancerV2PoolsCache } from './balancer_v2_utils';
 export { CreamPoolsCache } from './cream_utils';
-export { PoolsCache } from './pools_cache';
+export { AbstractPoolsCache, PoolsCache } from './pools_cache';

packages/asset-swapper/src/utils/market_operation_utils/pools_cache/no_op_pools_cache.ts

@@ -0,0 +1,21 @@
+import { Pool, PoolsCache } from './pools_cache';
+
+// tslint:disable:prefer-function-over-method
+
+export class NoOpPoolsCache implements PoolsCache {
+    public async getFreshPoolsForPairAsync(
+        _takerToken: string,
+        _makerToken: string,
+        _timeoutMs?: number | undefined,
+    ): Promise<Pool[]> {
+        return [];
+    }
+
+    public getPoolAddressesForPair(_takerToken: string, _makerToken: string): string[] {
+        return [];
+    }
+
+    public isFresh(_takerToken: string, _makerToken: string): boolean {
+        return true;
+    }
+}

packages/asset-swapper/src/utils/market_operation_utils/pools_cache/pools_cache.ts

@@ -10,15 +10,29 @@ export interface CacheValue {
 // tslint:disable:custom-no-magic-numbers
 // Cache results for 30mins
 const DEFAULT_CACHE_TIME_MS = (ONE_HOUR_IN_SECONDS / 2) * ONE_SECOND_MS;
-const DEFAULT_TIMEOUT_MS = 1000;
+const DEFAULT_TIMEOUT_MS = 3000;
 // tslint:enable:custom-no-magic-numbers
 
-export abstract class PoolsCache {
-    protected static _isExpired(value: CacheValue): boolean {
+export interface PoolsCache {
+    getFreshPoolsForPairAsync(takerToken: string, makerToken: string, timeoutMs?: number): Promise<Pool[]>;
+    getPoolAddressesForPair(takerToken: string, makerToken: string): string[];
+    isFresh(takerToken: string, makerToken: string): boolean;
+}
+
+export abstract class AbstractPoolsCache implements PoolsCache {
+    protected static _getKey(takerToken: string, makerToken: string): string {
+        return `${takerToken}-${makerToken}`;
+    }
+
+    protected static _isExpired(value: CacheValue | undefined): boolean {
+        if (value === undefined) {
+            return true;
+        }
         return Date.now() >= value.expiresAt;
     }
+
     constructor(
-        protected readonly _cache: { [key: string]: CacheValue },
+        protected readonly _cache: Map<string, CacheValue>,
         protected readonly _cacheTimeMs: number = DEFAULT_CACHE_TIME_MS,
     ) {}
 
@@ -31,47 +45,42 @@ export abstract class PoolsCache {
         return Promise.race([this._getAndSaveFreshPoolsForPairAsync(takerToken, makerToken), timeout]);
     }
 
-    public getCachedPoolAddressesForPair(
-        takerToken: string,
-        makerToken: string,
-        ignoreExpired: boolean = true,
-    ): string[] | undefined {
-        const key = JSON.stringify([takerToken, makerToken]);
-        const value = this._cache[key];
-        if (ignoreExpired) {
-            return value === undefined ? [] : value.pools.map(pool => pool.id);
-        }
-        if (!value) {
-            return undefined;
-        }
-        if (PoolsCache._isExpired(value)) {
-            return undefined;
-        }
-        return (value || []).pools.map(pool => pool.id);
+    /**
+     * Returns pool addresses (can be stale) for a pair.
+     *
+     * An empty array will be returned if cache does not exist.
+     */
+    public getPoolAddressesForPair(takerToken: string, makerToken: string): string[] {
+        const value = this._getValue(takerToken, makerToken);
+        return value === undefined ? [] : value.pools.map(pool => pool.id);
     }
 
     public isFresh(takerToken: string, makerToken: string): boolean {
-        const cached = this.getCachedPoolAddressesForPair(takerToken, makerToken, false);
-        return cached !== undefined;
+        const value = this._getValue(takerToken, makerToken);
+        return !AbstractPoolsCache._isExpired(value);
+    }
+
+    protected _getValue(takerToken: string, makerToken: string): CacheValue | undefined {
+        const key = AbstractPoolsCache._getKey(takerToken, makerToken);
+        return this._cache.get(key);
     }
 
     protected async _getAndSaveFreshPoolsForPairAsync(takerToken: string, makerToken: string): Promise<Pool[]> {
-        const key = JSON.stringify([takerToken, makerToken]);
-        const value = this._cache[key];
-        if (value === undefined || value.expiresAt >= Date.now()) {
-            const pools = await this._fetchPoolsForPairAsync(takerToken, makerToken);
-            const expiresAt = Date.now() + this._cacheTimeMs;
-            this._cachePoolsForPair(takerToken, makerToken, pools, expiresAt);
+        const key = AbstractPoolsCache._getKey(takerToken, makerToken);
+        const value = this._cache.get(key);
+        if (!AbstractPoolsCache._isExpired(value)) {
+            return value!.pools;
         }
-        return this._cache[key].pools;
+
+        const pools = await this._fetchPoolsForPairAsync(takerToken, makerToken);
+        const expiresAt = Date.now() + this._cacheTimeMs;
+        this._cachePoolsForPair(takerToken, makerToken, pools, expiresAt);
+        return pools;
     }
 
     protected _cachePoolsForPair(takerToken: string, makerToken: string, pools: Pool[], expiresAt: number): void {
-        const key = JSON.stringify([takerToken, makerToken]);
-        this._cache[key] = {
-            pools,
-            expiresAt,
-        };
+        const key = AbstractPoolsCache._getKey(takerToken, makerToken);
+        this._cache.set(key, { pools, expiresAt });
     }
 
     protected abstract _fetchPoolsForPairAsync(takerToken: string, makerToken: string): Promise<Pool[]>;

packages/asset-swapper/src/utils/market_operation_utils/sampler_operations.ts

@@ -56,7 +56,7 @@ import {
 } from './constants';
 import { getGeistInfoForPair } from './geist_utils';
 import { getLiquidityProvidersForPair } from './liquidity_provider_utils';
-import { BalancerPoolsCache, BalancerV2PoolsCache, CreamPoolsCache } from './pools_cache';
+import { BalancerPoolsCache, BalancerV2PoolsCache, CreamPoolsCache, PoolsCache } from './pools_cache';
 import { BalancerV2SwapInfoCache } from './pools_cache/balancer_v2_utils_new';
 import { SamplerContractOperation } from './sampler_contract_operation';
 import { SamplerNoOperation } from './sampler_no_operation';
@@ -114,10 +114,10 @@ export const TWO_HOP_SOURCE_FILTERS = SourceFilters.all().exclude([
 export const BATCH_SOURCE_FILTERS = SourceFilters.all().exclude([ERC20BridgeSource.MultiHop, ERC20BridgeSource.Native]);
 
 export interface PoolsCacheMap {
-    [ERC20BridgeSource.Balancer]: BalancerPoolsCache;
+    [ERC20BridgeSource.Balancer]: PoolsCache;
     [ERC20BridgeSource.BalancerV2]: BalancerV2SwapInfoCache | undefined;
-    [ERC20BridgeSource.Beethovenx]: BalancerV2PoolsCache | undefined;
-    [ERC20BridgeSource.Cream]: CreamPoolsCache;
+    [ERC20BridgeSource.Beethovenx]: PoolsCache;
+    [ERC20BridgeSource.Cream]: PoolsCache;
 }
 
 // tslint:disable:no-inferred-empty-object-type no-unbound-method
@@ -156,8 +156,8 @@ export class SamplerOperations {
             ? poolsCaches
             : {
                   [ERC20BridgeSource.Beethovenx]: BalancerV2PoolsCache.createBeethovenXPoolCache(chainId),
-                  [ERC20BridgeSource.Balancer]: new BalancerPoolsCache(),
-                  [ERC20BridgeSource.Cream]: new CreamPoolsCache(),
+                  [ERC20BridgeSource.Balancer]: BalancerPoolsCache.create(chainId),
+                  [ERC20BridgeSource.Cream]: CreamPoolsCache.create(chainId),
                   [ERC20BridgeSource.BalancerV2]:
                       BALANCER_V2_VAULT_ADDRESS_BY_CHAIN[chainId] === NULL_ADDRESS
                           ? undefined
@@ -1592,20 +1592,17 @@ export class SamplerOperations {
                                 ),
                         ];
                     case ERC20BridgeSource.Balancer:
-                        return (
-                            this.poolsCaches[ERC20BridgeSource.Balancer].getCachedPoolAddressesForPair(
-                                takerToken,
-                                makerToken,
-                            ) || []
-                        ).map(balancerPool =>
-                            this.getBalancerSellQuotes(
-                                balancerPool,
-                                makerToken,
-                                takerToken,
-                                takerFillAmounts,
-                                ERC20BridgeSource.Balancer,
-                            ),
-                        );
+                        return this.poolsCaches[ERC20BridgeSource.Balancer]
+                            .getPoolAddressesForPair(takerToken, makerToken)
+                            .map(balancerPool =>
+                                this.getBalancerSellQuotes(
+                                    balancerPool,
+                                    makerToken,
+                                    takerToken,
+                                    takerFillAmounts,
+                                    ERC20BridgeSource.Balancer,
+                                ),
+                            );
                     case ERC20BridgeSource.BalancerV2: {
                         const cache = this.poolsCaches[source];
                         if (!cache) {
@@ -1624,18 +1621,14 @@ export class SamplerOperations {
                     }
                     case ERC20BridgeSource.Beethovenx: {
                         const cache = this.poolsCaches[source];
-                        if (cache === undefined) {
-                            return [];
-                        }
-                        const poolIds = cache.getCachedPoolAddressesForPair(takerToken, makerToken) || [];
-
+                        const poolAddresses = cache.getPoolAddressesForPair(takerToken, makerToken);
                         const vault = BEETHOVEN_X_VAULT_ADDRESS_BY_CHAIN[this.chainId];
                         if (vault === NULL_ADDRESS) {
                             return [];
                         }
-                        return poolIds.map(poolId =>
+                        return poolAddresses.map(poolAddress =>
                             this.getBalancerV2SellQuotes(
-                                { poolId, vault },
+                                { poolId: poolAddress, vault },
                                 makerToken,
                                 takerToken,
                                 takerFillAmounts,
@@ -1644,20 +1637,17 @@ export class SamplerOperations {
                         );
                     }
                     case ERC20BridgeSource.Cream:
-                        return (
-                            this.poolsCaches[ERC20BridgeSource.Cream].getCachedPoolAddressesForPair(
-                                takerToken,
-                                makerToken,
-                            ) || []
-                        ).map(creamPool =>
-                            this.getBalancerSellQuotes(
-                                creamPool,
-                                makerToken,
-                                takerToken,
-                                takerFillAmounts,
-                                ERC20BridgeSource.Cream,
-                            ),
-                        );
+                        return this.poolsCaches[ERC20BridgeSource.Cream]
+                            .getPoolAddressesForPair(takerToken, makerToken)
+                            .map(creamPool =>
+                                this.getBalancerSellQuotes(
+                                    creamPool,
+                                    makerToken,
+                                    takerToken,
+                                    takerFillAmounts,
+                                    ERC20BridgeSource.Cream,
+                                ),
+                            );
                     case ERC20BridgeSource.Dodo:
                         if (!isValidAddress(DODOV1_CONFIG_BY_CHAIN_ID[this.chainId].registry)) {
                             return [];
@@ -1948,20 +1938,17 @@ export class SamplerOperations {
                                 ),
                         ];
                     case ERC20BridgeSource.Balancer:
-                        return (
-                            this.poolsCaches[ERC20BridgeSource.Balancer].getCachedPoolAddressesForPair(
-                                takerToken,
-                                makerToken,
-                            ) || []
-                        ).map(poolAddress =>
-                            this.getBalancerBuyQuotes(
-                                poolAddress,
-                                makerToken,
-                                takerToken,
-                                makerFillAmounts,
-                                ERC20BridgeSource.Balancer,
-                            ),
-                        );
+                        return this.poolsCaches[ERC20BridgeSource.Balancer]
+                            .getPoolAddressesForPair(takerToken, makerToken)
+                            .map(poolAddress =>
+                                this.getBalancerBuyQuotes(
+                                    poolAddress,
+                                    makerToken,
+                                    takerToken,
+                                    makerFillAmounts,
+                                    ERC20BridgeSource.Balancer,
+                                ),
+                            );
                     case ERC20BridgeSource.BalancerV2: {
                         const cache = this.poolsCaches[source];
                         if (!cache) {
@@ -1986,11 +1973,7 @@ export class SamplerOperations {
                     }
                     case ERC20BridgeSource.Beethovenx: {
                         const cache = this.poolsCaches[source];
-                        if (cache === undefined) {
-                            return [];
-                        }
-                        const poolIds = cache.getCachedPoolAddressesForPair(takerToken, makerToken) || [];
-
+                        const poolIds = cache.getPoolAddressesForPair(takerToken, makerToken) || [];
                         const vault = BEETHOVEN_X_VAULT_ADDRESS_BY_CHAIN[this.chainId];
                         if (vault === NULL_ADDRESS) {
                             return [];
@@ -2006,20 +1989,17 @@ export class SamplerOperations {
                         );
                     }
                     case ERC20BridgeSource.Cream:
-                        return (
-                            this.poolsCaches[ERC20BridgeSource.Cream].getCachedPoolAddressesForPair(
-                                takerToken,
-                                makerToken,
-                            ) || []
-                        ).map(poolAddress =>
-                            this.getBalancerBuyQuotes(
-                                poolAddress,
-                                makerToken,
-                                takerToken,
-                                makerFillAmounts,
-                                ERC20BridgeSource.Cream,
-                            ),
-                        );
+                        return this.poolsCaches[ERC20BridgeSource.Cream]
+                            .getPoolAddressesForPair(takerToken, makerToken)
+                            .map(poolAddress =>
+                                this.getBalancerBuyQuotes(
+                                    poolAddress,
+                                    makerToken,
+                                    takerToken,
+                                    makerFillAmounts,
+                                    ERC20BridgeSource.Cream,
+                                ),
+                            );
                     case ERC20BridgeSource.Dodo:
                         if (!isValidAddress(DODOV1_CONFIG_BY_CHAIN_ID[this.chainId].registry)) {
                             return [];

packages/asset-swapper/src/utils/market_operation_utils/types.ts

@@ -617,15 +617,6 @@ export interface OptimizerResultWithReport extends OptimizerResult {
     priceComparisonsReport?: PriceComparisonsReport;
 }
 
-export type MarketDepthSide = Array<Array<DexSample<FillData>>>;
-
-export interface MarketDepth {
-    bids: MarketDepthSide;
-    asks: MarketDepthSide;
-    makerTokenDecimals: number;
-    takerTokenDecimals: number;
-}
-
 export interface MarketSideLiquidity {
     side: MarketOperation;
     inputAmount: BigNumber;

packages/asset-swapper/src/utils/protocol_fee_utils.ts

@@ -6,28 +6,36 @@ import { SwapQuoterError } from '../types';
 
 const MAX_ERROR_COUNT = 5;
 
+interface GasOracleResponse {
+    result: {
+        // gas price in wei
+        fast: number;
+    };
+}
+
 export class ProtocolFeeUtils {
     private static _instance: ProtocolFeeUtils;
-    private readonly _ethGasStationUrl!: string;
+    private readonly _zeroExGasApiUrl: string;
     private readonly _gasPriceHeart: any;
     private _gasPriceEstimation: BigNumber = constants.ZERO_AMOUNT;
     private _errorCount: number = 0;
 
     public static getInstance(
         gasPricePollingIntervalInMs: number,
-        ethGasStationUrl: string = constants.ETH_GAS_STATION_API_URL,
+        zeroExGasApiUrl: string = constants.ZERO_EX_GAS_API_URL,
         initialGasPrice: BigNumber = constants.ZERO_AMOUNT,
     ): ProtocolFeeUtils {
         if (!ProtocolFeeUtils._instance) {
             ProtocolFeeUtils._instance = new ProtocolFeeUtils(
                 gasPricePollingIntervalInMs,
-                ethGasStationUrl,
+                zeroExGasApiUrl,
                 initialGasPrice,
             );
         }
         return ProtocolFeeUtils._instance;
     }
 
+    /** @returns gas price (in wei) */
     public async getGasPriceEstimationOrThrowAsync(shouldHardRefresh?: boolean): Promise<BigNumber> {
         if (this._gasPriceEstimation.eq(constants.ZERO_AMOUNT)) {
             return this._getGasPriceFromGasStationOrThrowAsync();
@@ -48,27 +56,21 @@ export class ProtocolFeeUtils {
 
     private constructor(
         gasPricePollingIntervalInMs: number,
-        ethGasStationUrl: string = constants.ETH_GAS_STATION_API_URL,
+        zeroExGasApiUrl: string = constants.ZERO_EX_GAS_API_URL,
         initialGasPrice: BigNumber = constants.ZERO_AMOUNT,
     ) {
         this._gasPriceHeart = heartbeats.createHeart(gasPricePollingIntervalInMs);
         this._gasPriceEstimation = initialGasPrice;
-        this._ethGasStationUrl = ethGasStationUrl;
+        this._zeroExGasApiUrl = zeroExGasApiUrl;
         this._initializeHeartBeat();
     }
 
     // tslint:disable-next-line: prefer-function-over-method
     private async _getGasPriceFromGasStationOrThrowAsync(): Promise<BigNumber> {
         try {
-            const res = await fetch(this._ethGasStationUrl);
-            const gasInfo = await res.json();
-            // Eth Gas Station result is gwei * 10
-            // tslint:disable-next-line:custom-no-magic-numbers
-            const BASE_TEN = 10;
-            const gasPriceGwei = new BigNumber(gasInfo.fast / BASE_TEN);
-            // tslint:disable-next-line:custom-no-magic-numbers
-            const unit = new BigNumber(BASE_TEN).pow(9);
-            const gasPriceWei = unit.times(gasPriceGwei);
+            const res = await fetch(this._zeroExGasApiUrl);
+            const gasInfo: GasOracleResponse = await res.json();
+            const gasPriceWei = new BigNumber(gasInfo.result.fast);
             // Reset the error count to 0 once we have a successful response
             this._errorCount = 0;
             return gasPriceWei;

packages/asset-swapper/test/market_operation_utils_test.ts

@@ -24,7 +24,7 @@ import {
     SOURCE_FLAGS,
     ZERO_AMOUNT,
 } from '../src/utils/market_operation_utils/constants';
-import { PoolsCache } from '../src/utils/market_operation_utils/pools_cache';
+import { AbstractPoolsCache } from '../src/utils/market_operation_utils/pools_cache';
 import { DexOrderSampler } from '../src/utils/market_operation_utils/sampler';
 import { BATCH_SOURCE_FILTERS } from '../src/utils/market_operation_utils/sampler_operations';
 import { SourceFilters } from '../src/utils/market_operation_utils/source_filters';
@@ -98,9 +98,9 @@ async function getMarketBuyOrdersAsync(
     return utils.getOptimizerResultAsync(nativeOrders, makerAmount, MarketOperation.Buy, opts);
 }
 
-class MockPoolsCache extends PoolsCache {
+class MockPoolsCache extends AbstractPoolsCache {
     constructor(private readonly _handler: (takerToken: string, makerToken: string) => Pool[]) {
-        super({});
+        super(new Map());
     }
     protected async _fetchPoolsForPairAsync(takerToken: string, makerToken: string): Promise<Pool[]> {
         return this._handler(takerToken, makerToken);

packages/asset-swapper/test/pools_cache_test.ts

@@ -28,12 +28,12 @@ describe('Pools Caches for Balancer-based sampling', () => {
         expect(pools.length).greaterThan(0, `Failed to find any pools for ${takerToken} and ${makerToken}`);
         expect(pools[0]).not.undefined();
         expect(Object.keys(pools[0])).to.include.members(poolKeys);
-        const cachedPoolIds = cache.getCachedPoolAddressesForPair(takerToken, makerToken);
+        const cachedPoolIds = cache.getPoolAddressesForPair(takerToken, makerToken);
         expect(cachedPoolIds).to.deep.equal(pools.map(p => p.id));
     }
 
     describe('BalancerPoolsCache', () => {
-        const cache = new BalancerPoolsCache();
+        const cache = BalancerPoolsCache.create(ChainId.Mainnet);
         it('fetches pools', async () => {
             const pairs = [
                 [usdcAddress, daiAddress],
@@ -58,15 +58,14 @@ describe('Pools Caches for Balancer-based sampling', () => {
                 [wftmAddress, fantomWethAddress],
             ];
 
-            expect(cache).not.null();
             await Promise.all(
-                pairs.map(async ([takerToken, makerToken]) => fetchAndAssertPoolsAsync(cache!, takerToken, makerToken)),
+                pairs.map(async ([takerToken, makerToken]) => fetchAndAssertPoolsAsync(cache, takerToken, makerToken)),
             );
         });
     });
 
     describe('CreamPoolsCache', () => {
-        const cache = new CreamPoolsCache();
+        const cache = CreamPoolsCache.create(ChainId.Mainnet);
         it('fetches pools', async () => {
             const pairs = [
                 [usdcAddress, creamAddress],

packages/asset-swapper/test/protocol_fee_utils_test.ts

@@ -0,0 +1,45 @@
+import * as chai from 'chai';
+import 'mocha';
+import { rest } from 'msw';
+import { setupServer } from 'msw/node';
+
+import { ProtocolFeeUtils } from '../src';
+
+import { chaiSetup } from './utils/chai_setup';
+chaiSetup.configure();
+const expect = chai.expect;
+
+const server = setupServer(
+    rest.get('https://mock-0x-gas-api.org/median', (_req, res, ctx) => {
+        return res(
+            ctx.json({
+                result: {
+                    source: 'MEDIAN',
+                    timestamp: 1659386474,
+                    instant: 22000000000,
+                    fast: 18848500000,
+                    standard: 14765010000,
+                    low: 13265000000,
+                },
+            }),
+        );
+    }),
+);
+
+describe('ProtocolFeeUtils', () => {
+    describe('getGasPriceEstimationOrThrowAsync', () => {
+        beforeEach(() => {
+            server.listen();
+        });
+
+        afterEach(() => {
+            server.close();
+        });
+
+        it('parses fast gas price response correctly', async () => {
+            const utils = ProtocolFeeUtils.getInstance(420000, 'https://mock-0x-gas-api.org/median');
+            const gasPrice = await utils.getGasPriceEstimationOrThrowAsync();
+            expect(gasPrice.toNumber()).to.eq(18848500000);
+        });
+    });
+});

packages/asset-swapper/tslint.json

@@ -1,6 +1,7 @@
 {
     "extends": ["@0x/tslint-config"],
     "rules": {
+        "custom-no-magic-numbers": false,
         "max-file-line-count": false,
         "binary-expression-operand-order": false
     },