This content applies to WaaS 1.0 only. We highly recommend that you upgrade to WaaS 2.0.
Overview
Web3 transactions typically involve interacting with smart contracts on the blockchain, with applications extending to decentralized applications (dApps), non-fungible tokens (NFTs), and beyond. This guide will outline how developers can create Web3 transactions in MPC Wallets using the APIs provided by Cobo. Note: The code samples below are only applicable to Web3 Wallets under the MPC Wallets.Code Samples
Initiating a withdraw transaction using Web3 Wallets (e.g., sending 0.01 ETH)
Step 1: Initialize the mpc_client Step 2: Create the withdraw transactionfrom cobo_custody.client.mpc_client import MPCClient
from cobo_custody.config import DEVELOP_ENV
from cobo_custody.signer.local_signer import LocalSigner
import time
api_secret = "your api secret" # your wallet api secret
chain_code = "ETH" # your target chain
coin_code = "ETH" # your target coin
amount = "100000000000000000" # withdraw amount：0.01ETH
from_address = "your mpc wallet address" # your mpc wallet address
to_address = "to address" # to address
# init cobo client
mpc_client = MPCClient(signer=LocalSigner(api_secret), env=DEVELOP_ENV, debug=False)
request_id = f"MPCTransaction-{int(time.time() * 1000)}" # your custom request_id
# create withdraw transaction
response = mpc_client.create_transaction(
coin=coin_code,
request_id=request_id,
amount=amount,
from_addr=from_address,
to_addr=to_address,
gas_price=6500000000,
gas_limit=21000,
)
print(f"Withdraw: {response.result}")
package com.cobo.custody.api.client.impl;
import java.math.BigDecimal;
import java.math.BigInteger;
import com.cobo.custody.api.client.CoboApiClientFactory;
import com.cobo.custody.api.client.CoboMPCApiRestClient;
import com.cobo.custody.api.client.config.Env;
import com.cobo.custody.api.client.domain.ApiResponse;
import com.cobo.custody.api.client.domain.transaction.MPCPostTransaction;
public class CobоCustodyApiClientExample {
public static void main(String[] args) {
String apiSecret = "your_api_secret"; // your wallet api secret
// init client
CoboMPCApiRestClient mpcClient = CoboApiClientFactory.newInstance(
new LocalSigner(apiSecret),
Env.DEV,
false).newMPCRestClient();
// create withdraw transaction
String coin = "GETH";
String requestId = String.valueOf(System.currentTimeMillis());
String fromAddr = "your mpc wallet address";
String toAddr = "to address";
BigInteger amount = new BigInteger("100000000000000000");
String toAddressDetails = null;
BigDecimal fee = null;
BigInteger gasPrice = new BigInteger("6500000000");
BigInteger gasLimit = new BigInteger("21000");
Integer operation = null;
String extraParameters = null;
ApiResponse<MPCPostTransaction> res = mpcClient.createTransaction(coin, requestId, amount, fromAddr, toAddr,
toAddressDetails, fee, gasPrice, gasLimit, operation, extraParameters, null, null, null, null);
System.out.println("Withdraw: " + res.getResult());
}
}
Interacting with a smart contract using Web3 Wallets
Step 1: Initialize the mpc_client Step 2: Pass in calldata to call a smart contractfrom cobo_custody.client.mpc_client import MPCClient
from cobo_custody.config import DEVELOP_ENV
from cobo_custody.signer.local_signer import LocalSigner
import time
api_secret = "your api secret" # your wallet api secret
chain_code = "ETH" # your target chain
coin_code = "ETH" # your target coin
amount = "0"
from_address = "your mpc wallet address" # your mpc wallet address
to_address = "contract address" # contract address
extra_parameters = '{"calldata": "0xa8059cbb000000000000000000000000971948873f869e4517311b190d7eb31e30eba0ef000000000000000000000000000000000000000000000000002386f26fc10000"}' # use calldata to call or deploy contract
# init cobo client
mpc_client = MPCClient(signer=LocalSigner(api_secret), env=DEVELOP_ENV, debug=False)
request_id = f"MPCTransaction-{int(time.time() * 1000)}" # your custom request_id
response = mpc_client.create_transaction(
coin=coin_code,
request_id=request_id,
amount=amount,
from_addr=from_address,
to_addr=to_address,
gas_price=6500000000,
gas_limit=22385,
extra_parameters=extra_parameters,
)
print(f"call contract: {response.result}")
package com.cobo.custody.api.client.impl;
import java.math.BigDecimal;
import java.math.BigInteger;
import com.cobo.custody.api.client.CoboApiClientFactory;
import com.cobo.custody.api.client.CoboMPCApiRestClient;
import com.cobo.custody.api.client.config.Env;
import com.cobo.custody.api.client.domain.ApiResponse;
import com.cobo.custody.api.client.domain.transaction.MPCPostTransaction;
public class CobоCustodyApiClientExample {
public static void main(String[] args) {
String apiSecret = "your_api_secret"; // your wallet api secret
// init client
CoboMPCApiRestClient mpcClient = CoboApiClientFactory.newInstance(
new LocalSigner(apiSecret),
Env.DEV,
false).newMPCRestClient();
// create withdraw transaction
String coin = "GETH";
String requestId = String.valueOf(System.currentTimeMillis());
String fromAddr = "your mpc wallet address";
String toAddr = "contract address";
BigInteger amount = new BigInteger("0");
String toAddressDetails = null;
BigDecimal fee = null;
BigInteger gasPrice = new BigInteger("6500000000");
BigInteger gasLimit = new BigInteger("22385");
Integer operation = null;
String extraParameters = "{\"calldata\": \"0xa8059cbb000000000000000000000000971948873f869e4517311b190d7eb31e30eba0ef000000000000000000000000000000000000000000000000002386f26fc10000\"}"
ApiResponse<MPCPostTransaction> res = mpcClient.createTransaction(coin, requestId, amount, fromAddr, toAddr,
toAddressDetails, fee, gasPrice, gasLimit, operation, extraParameters, null, null, null, null);
System.out.println("call contract: " + res.getResult());
}
}
For more information on the ‘create_transaction’ endpoint, please click here.