[DRAFT] BNB Chain / PancakeSwap connector

gateway/package.json

@@ -24,17 +24,20 @@
     "@ethersproject/experimental": "^5.3.0",
     "@harmony-js/core": "^0.1.57",
     "@harmony-js/utils": "^0.1.56",
+    "@pancakeswap/sdk": "^2.4.5",
     "@pangolindex/sdk": "^1.1.0",
     "@project-serum/serum": "^0.13.61",
     "@solana/spl-token-registry": "^0.2.700",
     "@solana/web3.js": "^1.31.0",
     "@sushiswap/sdk": "^5.0.0-canary.116",
-    "@traderjoe-xyz/sdk": "^1.6.1",
+    "@traderjoe-xyz/sdk": "^1.6.4",
     "@types/fs-extra": "^9.0.13",
     "@types/lodash": "^4.14.178",
     "@types/minimist": "^1.2.2",
     "@types/morgan": "^1.9.3",
+    "@types/node-fetch": "^2.6.2",
     "@types/uuid": "^8.3.4",
+    "@uniswap/router-sdk": "^1.0.5",
     "@uniswap/sdk": "^3.0.3",
     "@uniswap/sdk-core": "^3.0.0",
     "@uniswap/smart-order-router": "^2.5.26",

gateway/src/app.ts

@@ -24,6 +24,7 @@ import { UniswapConfig } from './connectors/uniswap/uniswap.config';
 import { AvailableNetworks } from './services/config-manager-types';
 import morgan from 'morgan';
 import { SushiswapConfig } from './connectors/sushiswap/sushiswap.config';
+import { PancakeswapConfig } from './connectors/pancakeswap/pancakeswap.config';
 
 const swaggerUi = require('swagger-ui-express');
 
@@ -68,6 +69,7 @@ interface ConnectorsResponse {
   pangolin: Array<AvailableNetworks>;
   sushiswap: Array<AvailableNetworks>;
   traderjoe: Array<AvailableNetworks>;
+  pancakeswap: Array<AvailableNetworks>;
 }
 
 gatewayApp.get(
@@ -78,6 +80,7 @@ gatewayApp.get(
       pangolin: PangolinConfig.config.availableNetworks,
       sushiswap: SushiswapConfig.config.availableNetworks,
       traderjoe: TraderjoeConfig.config.availableNetworks,
+      pancakeswap: PancakeswapConfig.config.availableNetworks,
     });
   })
 );

gateway/src/chains/bsc/bep20_tokens_testnet.json

@@ -0,0 +1,20 @@
+{
+  "name": "testnet",
+  "tokens": [
+    {
+      "symbol": "WBNB",
+      "address": "0xae13d989daC2f0dEbFf460aC112a837C89BAa7cd",
+      "decimals": 18
+    },
+    {
+      "symbol": "BUSD",
+      "address": "0x615446C0Fd5eA8A5FD7fb763f3FC2C58774474F3",
+      "decimals": 18
+    },
+    {
+      "symbol": "USDT",
+      "address": " 0x7ef95a0fee0dd31b22626fa2e10ee6a223f8a684",
+      "decimals": 18
+    }
+  ]
+}

gateway/src/chains/bsc/bsc.ts

@@ -0,0 +1,93 @@
+import abi from '../../services/ethereum.abi.json';
+import { logger } from '../../services/logger';
+import { Contract, Transaction, Wallet } from 'ethers';
+import { EthereumBase } from '../../services/ethereum-base';
+import { getEthereumConfig as getBscConfig } from '../ethereum/ethereum.config';
+import { Provider } from '@ethersproject/abstract-provider';
+import { Ethereumish } from '../../services/common-interfaces';
+import { ConfigManagerV2 } from '../../services/config-manager-v2';
+import { replaceOrAppend } from '../../services/base';
+import { PancakeswapConfig } from '../../connectors/pancakeswap/pancakeswap.config';
+
+export class BSC extends EthereumBase implements Ethereumish {
+  private static _instances: { [name: string]: BSC };
+  private _gasPrice: number;
+  private _nativeTokenSymbol: string;
+  private _chain: string;
+
+  private constructor(network: string) {
+    const config = getBscConfig('bsc', network);
+    super(
+      'bsc',
+      config.network.chainID,
+      replaceOrAppend(config.network.nodeURL, config.nodeAPIKey),
+      config.network.tokenListSource,
+      config.network.tokenListType,
+      config.manualGasPrice,
+      config.gasLimit,
+      ConfigManagerV2.getInstance().get('database.nonceDbPath'),
+      ConfigManagerV2.getInstance().get('database.transactionDbPath')
+    );
+    this._chain = config.network.name;
+    this._nativeTokenSymbol = config.nativeCurrencySymbol;
+    this._gasPrice = config.manualGasPrice;
+  }
+
+  public static getInstance(network: string): BSC {
+    if (BSC._instances === undefined) {
+      BSC._instances = {};
+    }
+    if (!(network in BSC._instances)) {
+      BSC._instances[network] = new BSC(network);
+    }
+
+    return BSC._instances[network];
+  }
+
+  public static getConnectedInstances(): { [name: string]: BSC } {
+    return BSC._instances;
+  }
+
+  // getters
+
+  public get gasPrice(): number {
+    return this._gasPrice;
+  }
+
+  public get nativeTokenSymbol(): string {
+    return this._nativeTokenSymbol;
+  }
+
+  public get chain(): string {
+    return this._chain;
+  }
+
+  getContract(tokenAddress: string, signerOrProvider?: Wallet | Provider) {
+    return new Contract(tokenAddress, abi.ERC20Abi, signerOrProvider);
+  }
+
+  getSpender(reqSpender: string): string {
+    let spender: string;
+    if (reqSpender === 'pancakeswap') {
+      spender = PancakeswapConfig.config.routerAddress(this._chain);
+    } else {
+      spender = reqSpender;
+    }
+    return spender;
+  }
+
+  // cancel transaction
+  async cancelTx(wallet: Wallet, nonce: number): Promise<Transaction> {
+    logger.info(
+      'Canceling any existing transaction(s) with nonce number ' + nonce + '.'
+    );
+    return super.cancelTxWithGasPrice(wallet, nonce, this._gasPrice * 2);
+  }
+
+  async close() {
+    await super.close();
+    if (this._chain in BSC._instances) {
+      delete BSC._instances[this._chain];
+    }
+  }
+}

gateway/src/chains/bsc/bsc.validators.ts

@@ -0,0 +1,35 @@
+import {
+  mkRequestValidator,
+  mkValidator,
+  RequestValidator,
+  Validator,
+  validateAmount,
+  validateToken,
+  validateTokenSymbols,
+} from '../../services/validators';
+import {
+  isAddress,
+  validateNonce,
+  validateAddress,
+} from '../ethereum/ethereum.validators';
+
+export const invalidSpenderError: string =
+  'The spender param is not a valid BSC address (0x followed by 40 hexidecimal characters).';
+
+// given a request, look for a key called spender that is 'uniswap' or an Ethereum address
+export const validateSpender: Validator = mkValidator(
+  'spender',
+  invalidSpenderError,
+  (val) => typeof val === 'string' && (val === 'pancakeswap' || isAddress(val))
+);
+
+export const validateBSCApproveRequest: RequestValidator = mkRequestValidator([
+  validateAddress,
+  validateSpender,
+  validateToken,
+  validateAmount,
+  validateNonce,
+]);
+
+export const validateBSCAllowancesRequest: RequestValidator =
+  mkRequestValidator([validateAddress, validateSpender, validateTokenSymbols]);

gateway/src/connectors/connectors.routes.ts

@@ -1,5 +1,6 @@
 import { Router } from 'express';
 import { asyncHandler } from '../services/error-handler';
+import { PancakeswapConfig } from './pancakeswap/pancakeswap.config';
 import { PangolinConfig } from './pangolin/pangolin.config';
 import { SushiswapConfig } from './sushiswap/sushiswap.config';
 import { TraderjoeConfig } from './traderjoe/traderjoe.config';
@@ -38,6 +39,11 @@ export namespace ConnectorsRoutes {
             trading_type: TraderjoeConfig.config.tradingTypes,
             available_networks: TraderjoeConfig.config.availableNetworks,
           },
+          {
+            name: 'pancakeswap',
+            trading_type: PancakeswapConfig.config.tradingTypes,
+            available_networks: PancakeswapConfig.config.availableNetworks,
+          },
         ],
       });
     })

gateway/src/connectors/pancakeswap/pancakeswap.config.ts

@@ -0,0 +1,25 @@
+import { ConfigManagerV2 } from '../../services/config-manager-v2';
+import { AvailableNetworks } from '../../services/config-manager-types';
+
+export namespace PancakeswapConfig {
+  export interface NetworkConfig {
+    allowedSlippage: string;
+    ttl: number;
+    routerAddress: (network: string) => string;
+    tradingTypes: Array<string>;
+    availableNetworks: Array<AvailableNetworks>;
+  }
+
+  export const config: NetworkConfig = {
+    allowedSlippage: ConfigManagerV2.getInstance().get(
+      'pancakeswap.allowedSlippage'
+    ),
+    ttl: ConfigManagerV2.getInstance().get('pancakeswap.ttl'),
+    routerAddress: (network: string) =>
+      ConfigManagerV2.getInstance().get(
+        'pancakeswap.contractAddresses.' + network + '.routerAddress'
+      ),
+    tradingTypes: ['EVM_AMM'],
+    availableNetworks: [{ chain: 'bsc', networks: ['mainnet', 'testnet'] }],
+  };
+}