orionprotocol/orion-direct-swap-example

Description

Direct swap flow is following:

1. Request best path for swap from asset A to asset B

• best path can use multiple DEX pools
• e.g while swapping from asset A to asset B there can be path with better price like A -> other token -> B

2. Generate swap calldata based on best path
3. Make transaction based on calldata and current network conditions
4. Increase allowance for exchange contract
5. Make swap by sending built transaction
6. Exchange contract will execute all swap path atomically and check that you received desired output amount considering selected slippage

Example

1. Create new folder for project

mkdir orion-direct-swap-example && cd $_

2. Init package.json

pnpm init

3. Install dependencies

ethers library is used for interaction with blockchain

@orionprotocol/contracts contains Orion contracts ABI

pnpm i ethers @orionprotocol/contracts

4. Create main file src/index.ts

5. Import dependencies. add interfaces and constants

You need to choose API_URL based on your blockchain network. See list of available networks at section API_URL below

You don't need to change DECIMALS = 8. It's fixed for Orion internals

import { Wallet, JsonRpcProvider, parseUnits } from 'ethers';
import { Exchange__factory } from '@orionprotocol/contracts/lib/ethers-v6/factories/Exchange__factory';
import { ERC20__factory } from '@orionprotocol/contracts/lib/ethers-v6/factories/ERC20__factory';

interface SwapInfo {
  exchangeContractPath: any[],
  amountOut: number,
}

interface DirectSwapRequest {
  amount: string,
  minReturnAmount: string,
  receiverAddress: string,
  path: any[],
}

interface DirectSwapResult {
  calldata: string,
  swapDescription: any,
}

const SWAP_THROUGH_ORION_POOL_GAS_LIMIT = 600000;
const rpcUrl = 'https://bsc-dataseed1.binance.org/';
const API_URL = `https://trade.orion.xyz/bsc-mainnet`;
const DECIMALS = 8;

6. Configure data for swap. set asset to swap.

Set your seed phrase. this wallet should have atleast 0.002 BNB for network fees and 0.1 USDT as input asset

minReturnPercent is configuring max price slippage

const phrase = ''; // 12 words phrase
const amountIn = 0.1;
const assetIn = 'USDT';
const assetInDecimals = 18;
const assetOut = 'ORN';
const minReturnPercent = 0.99;

7. Load configuration. Setup provider. Load network data

This information will be used later to build transaction

(async () => {
  const {
    exchangeContractAddress,
    assetToAddress,
    swapExecutorContractAddress,
  } = await fetch(`${API_URL}/api/info`).then(o => o.json());

  const provider = new JsonRpcProvider(rpcUrl);
  const chainId = await provider.getNetwork().then(o => o.chainId);
  const gasPriceWei = await fetch(`${API_URL}/api/gasPrice`).then(o => o.json());

  // ...
})();

8. Setup wallet and approve Orion exchange contract to spend input asset

const wallet = Wallet.fromPhrase(phrase, provider);
console.log('wallet', wallet.address);

const assetInAddress = assetToAddress[assetIn];
console.log('increasing allowance to exchange contract...');
{
  const erc20 = ERC20__factory.connect(assetInAddress, wallet);
  const amount = parseUnits(amountIn.toFixed(assetInDecimals), assetInDecimals).toString();
  await erc20.approve(exchangeContractAddress, amount);
}

9. Request swap info. It will contain optimal path for swap and estimated output value

See section /backend/api/v1/swap below for details about request parameters

const swapInfo: SwapInfo = await fetch(`${API_URL}/backend/api/v1/swap?amountIn=${amountIn}&assetOut=${assetOut}&assetIn=${assetIn}&exchanges=pools`).then(res => res.json());
console.log('swapInfo', swapInfo);

10. Build swap request based on received best path

const { amountOut } = swapInfo;
const minReturnAmount = amountOut * minReturnPercent;

const swapRequest: DirectSwapRequest = {
  amount: parseUnits(amountIn.toFixed(DECIMALS), DECIMALS).toString(),
  minReturnAmount: parseUnits(minReturnAmount.toFixed(DECIMALS), DECIMALS).toString(),
  receiverAddress: wallet.address,
  path: swapInfo.exchangeContractPath,
};
console.log('swapRequest', swapRequest);

11. Generate calldata for swap response

const swapResponse: DirectSwapResult = await fetch(`${API_URL}/api/trade/generate-swap-calldata`, {
  method: 'POST',
  headers: {
    'Accept': 'application/json',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify(swapRequest),
}).then(res => res.json());
console.log('swapResponse', swapResponse);

12. Build transaction based on calldata and current network conditions

const { swapDescription, calldata } = swapResponse;
const exchangeContract = Exchange__factory.connect(exchangeContractAddress, provider);
const unsignedSwapThroughPoolsTx = await exchangeContract.swap.populateTransaction(
  swapExecutorContractAddress,
  swapDescription,
  new Uint8Array(0),
  calldata,
  {
    value: 0,
  }
);

unsignedSwapThroughPoolsTx.chainId = chainId;
unsignedSwapThroughPoolsTx.gasPrice = BigInt(gasPriceWei);
unsignedSwapThroughPoolsTx.from = wallet.address;
unsignedSwapThroughPoolsTx.gasLimit = BigInt(SWAP_THROUGH_ORION_POOL_GAS_LIMIT);
unsignedSwapThroughPoolsTx.nonce = await provider.getTransactionCount(wallet.address, 'pending');

13. Send transaction and wait for confirmation

console.log('sending tx...');
const swapThroughOrionPoolTxResponse = await wallet.sendTransaction(unsignedSwapThroughPoolsTx);
console.log('tx was sent', swapThroughOrionPoolTxResponse.hash, '| wait for confirmation...')

await swapThroughOrionPoolTxResponse.wait();
console.log('success swap');

14. Run example

tsx src/index.ts

PS: full example code is available in repo https://github.com/orionprotocol/orion-direct-swap-example

API_URL

Available blockchain networks:

• https://trade.orion.xyz/eth-mainnet
• https://trade.orion.xyz/bsc-mainnet
• https://trade.orion.xyz/polygon-mainnet
• https://trade.orion.xyz/opbnb-mainnet
• https://trade.orion.xyz/linea-mainnet

/backend/api/v1/swap

Available input parameters:

• amountIn - input amount to swap in decimals - e.g 10.85
• assetIn - input asset symbol - e.g USDT
• assetOut - output asset symbol - e.g ORN
• exchanges - configures which kind of exchanges to use DEXes, CEXes or both. Optionals parameter
  • example: pools, cex or empty string to use both