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Read Contract Method
Checking the state of a contract and verifying it.
Most quests verify by reading on-chain data and checking conditions.
At first, we obtain liquidity pools using the following method:
- Pool List from documentation
Deployment Addresses — Curve 1.0.0 documentation
Pool Address
- Retrieve meta pool info from meta pool factory contract
async function getFromMetaPoolFactory() {
const provider = new ethers.providers.JsonRpcProvider(process.env.RPC_MAINNET);
const metapool = new ethers.Contract("0xB9fC157394Af804a3578134A6585C0dc9cc990d4", abi, provider);
const addresses: Array<string> = [];
const numPools = await metapool.pool_count();
for (let i = 0; i < numPools; ++i) {
const addr = await metapool.pool_list(i);
console.log(`got metapool address ${addr}`);
addresses.push(addr.toLowerCase());
}
return addresses;
}
- Get V2 pool
- trycrypto2:0xd51a44d3fae010294c616388b506acda1bfaae46
- crveth:0x8301AE4fc9c624d1D396cbDAa1ed877821D7C511
- 1.Retrieve the transaction data (txdata) for the address. We can do this using an API such as EtherscanAPI or a blockchain explorer tool.
- 2.Inspect the txdata to see if any of the transactions include calls to the desired function.
- 3.If you find a transaction that includes a call to the function, we can verify that it was executed.
export const txFilter_22: EtherscanFilter = (tx: EtherscanTxItem) => {
// check tx target is a curve pool
if (deps.curvePools[tx.to] && tx.isError === "0") {
// check tx function name
const functionName: string = tx.functionName.split("(")[0];
if (functionName === "add_liquidity") {
return true;
}
}
return false;
};
const txs = await getEtherScanTx('homestead', address, etherscanApiKey)
let count = 0
txs.data.every((tx: EtherscanTxItem) => {
if (txFilter_22(tx)) { ++count; }
if (count >= value) {
// break the loop
return false
}
return true
})
if (count >= value) {
return [true, count]
}
else {
return [false, count]
}
Finally, if user get true result, they can mint curve pool object.
Curve Pool Object
In this case, we can check contract's read method is used to verify the balance of DAI.
We verify whether an address has a sufficient balance.
const DAI = new ethers.Contract(DAI_ADDRESS, ERC20ABI, provider);
DAIBalance = await DAI.balanceOf(useraddress);
Balance is easy to check. You can check DAI contract read method.
Dai Etherscan
Last modified 11mo ago