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Sending RPC Requests

Communication with the wallet is sent via RPC requests. This guide will show you how to send an RPC request and how to interpret responses.

Obtain a chain provider

With the steps mentioned in Provider Activation, get a chain provider for the networks you want to interact with. In the following examples we will use both ethereum and constellation providers.

TypeScript
const dagProvider = window.stargazer.getProvider("constellation");
const ethProvider = window.stargazer.getProvider("ethereum");

List available accounts

For listing available accounts in the wallet (and in some cases activating the providers) you can send the following calls to dag_accounts RPC method and eth_accounts RPC method.

Important

The account at index 0 will always be the active account in Stargazer. Both for Constellation and Ethereum providers.

TypeScript
const dagAccounts = await dagProvider.request({ method: "dag_accounts" });
console.log(dagAccounts);
// ["DAG88C9WDSKH451sisyEP3hAkgCKn5DN72fuwjfX", "DAG5pvyL8wQVEACYjEph9jouKQeH4J71Dn5HS25w"]

const ethAccounts = await ethProvider.request({ method: "eth_accounts" });
console.log(eth_accounts);
// ["0x567d0382442c5178105fC03bd52b8Db6Afb4fE40", "0xAab2C30c02016585EB36b7a0d5608Db787c1e44E"]

Read more about dag_accounts RPC method and eth_accounts RPC method.

Send an ETH contract call

For interaction with ethereum smart contracts you can use the eth_call RPC method and the eth_sendTransaction RPC method, respectively for read and write operations. In the following example we will be using the ethers package, and a demo conract from the Stargazer Demos. The ethers package will help us encode method parameters based on the contract's ABI. It is encouraged to use external libraries to encode contract call parameters.

Important

Interaction with smart contracts is done through an ABI (Application Binary Interface), you can read more about it in the Contract ABI Specification article from the solidity docs.

You can think about an ABI as any other programming interface, where you have defined method signatures and interaction abstractions without the actual implementation.

Send an ETH read call

In the next example we will use the greet method from the StargazerGreeter contract. It reads a greet string saved in the network state. For interacting with the contract we will create an ethers Contract instance, and therefore an ethers Web3Provider. In the background the ethers package will call eth_call for us.

TypeScript
import * as ethers from "ethers";

const ethersProvider = new ethers.providers.Web3Provider(ethProvider);

const StargazerGreeterAddress = "0x1DBF94D57ceb7b59de0b5efd1e85776aa97CbDb4";
const StargazerGreeterABI = [...[]]; // You can get StargazerGreeter's ABI from https://ropsten.etherscan.io/address/0x1dbf94d57ceb7b59de0b5efd1e85776aa97cbdb4#code;

const contract = new ethers.Contract(
StargazerGreeterAddress,
StargazerGreeterABI,
ethersProvider
);

await contract.greet();
// "Bon Matin!"

Send an ETH contract write call

In the next example we will use the setGreeting method from the StargazerGreeter contract. It sets a greet string in the network state. For interacting with the contract we will create an ethers Contract instance, and therefore an ethers Web3Provider. In the background the ethers package will call eth_sendTransaction for us.

Important

Write calls need to be confirmed by the user. Read more here.

TypeScript
import * as ethers from "ethers";

const ethersProvider = new ethers.providers.Web3Provider(ethProvider);

const signer = ethersProvider.getSigner();

const StargazerGreeterAddress = "0x1DBF94D57ceb7b59de0b5efd1e85776aa97CbDb4";
const StargazerGreeterABI = [...[]]; // You can get StargazerGreeter's ABI from https://ropsten.etherscan.io/address/0x1dbf94d57ceb7b59de0b5efd1e85776aa97cbdb4#code;

const contract = new ethers.Contract(
StargazerGreeterAddress,
StargazerGreeterABI,
signer
);

const greetingId = 1; // Bon Matin!

// We send a transaction to the network
const trxResponse = await contract.setGreeting(greetingId);

// We wait for confirmation
const trxReceipt = await library.waitForTransaction(trxResponse.hash);

console.log(trxReceipt.blockNumber);
// 12415408

Send ETH Transactions

As the ethereum chain reveals the eth_sendTransaction RPC method you can send any kind of transaction you need (Token Transfer, Contract Interaction, ETH Transfers, etc.).

Transfer ERC20 Tokens

You can send ERC20 tokens using the transfer method from any ERC20 contract. For interacting with the contract we will create an ethers Contract instance, and therefore an ethers Web3Provider. In the background the ethers package will call eth_sendTransaction for us.

TypeScript
import * as ethers from "ethers";

const ethersProvider = new ethers.providers.Web3Provider(ethProvider);

const signer = ethersProvider.getSigner();

const StargazerSampleTokenAddress =
"0x6235bFcC2eb5401932A03e043C9b7De4eDCe7A2f";
const StargazerSampleTokenABI = [...[]]; // You can get StargazerSampleToken's ABI from https://ropsten.etherscan.io/address/0x6235bFcC2eb5401932A03e043C9b7De4eDCe7A2f#code;

const contract = new ethers.Contract(
StargazerSampleTokenAddress,
StargazerSampleTokenABI,
signer
);

const receiverAddress = "0x....";
const receiveValue = ethers.utils.parseUnits("10", 18).toHexString(); // 10 SST

// We send a transaction to the network
const trxResponse = await contract.transfer(receiverAddress, receiveValue);

// We wait for confirmation
const trxReceipt = await library.waitForTransaction(trxResponse.hash);

console.log(trxReceipt.blockNumber);
// 12415408

Approve ERC20 token Spend

You can approve spend of ERC20 tokens to external contracts using the approve method from any ERC20 contract. For interacting with the contract we will create an ethers Contract instance, and therefore an ethers Web3Provider. In the background the ethers package will call eth_sendTransaction for us.

TypeScript
import * as ethers from "ethers";

const ethersProvider = new ethers.providers.Web3Provider(ethProvider);

const signer = ethersProvider.getSigner();

const StargazerSampleTokenAddress =
"0x6235bFcC2eb5401932A03e043C9b7De4eDCe7A2f";
const StargazerSampleTokenABI = [...[]]; // You can get StargazerSampleToken's ABI from https://ropsten.etherscan.io/address/0x6235bFcC2eb5401932A03e043C9b7De4eDCe7A2f#code;

const contract = new ethers.Contract(
StargazerSampleTokenAddress,
StargazerSampleTokenABI,
signer
);

const spenderAddress = "0x....";
const spendValue = ethers.utils.parseUnits("10", 18).toHexString(); // 10 SST

// We send a transaction to the network
const trxResponse = await contract.approve(spenderAddress, spendValue);

// We wait for confirmation
const trxReceipt = await library.waitForTransaction(trxResponse.hash);

console.log(trxReceipt.blockNumber);
// 12415408

Send ETH

You can send ETH (The ethereum's native currency) sending a simple transaction to the network. For interacting with the network we will create an ethers Web3Provider and an ethers Signer. In the background the ethers package will call eth_sendTransaction for us.

TypeScript
import * as ethers from "ethers";

const ethersProvider = new ethers.providers.Web3Provider(ethProvider);

const oneGwei = ethers.BigNumber.from(1 * 1e9).toHexString();

const signer = ethersProvider.getSigner();

// We send a transaction to the network
const trxResponse = await signer.sendTransaction({
to: "0x....",
value: oneGwei,
});

// We wait for confirmation
const trxReceipt = await library.waitForTransaction(trxResponse.hash);

console.log(trxReceipt.blockNumber);
// 12415408