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Interacting with Solana Contracts from a Node.js Client: Passing Strings as Bytes and Minting Tokens
As a developer working on smart contracts for the Solana blockchain, you’re likely familiar with the challenges of interacting with external programs or services. One common requirement is to pass data between your contract and an external client, such as a Node.js application. In this article, we’ll explore how to pass strings as bytes into a Solang contract using a Node.js client and mint tokens from that same client.
Prerequisites
Before diving into the code, make sure you have:
- A Solana Node installation set up on your machine.
- A Solang contract deployed on the mainnet with the necessary permissions for reading from the storage.
- A Node.js application installed on your local machine (we’ll use Express.js as an example).
Setting Up the Node.js Client
First, create a new Express.js project and install the required dependencies:
npm init -y
npm install express solana-typescript-sdk @types/solana-transaction-sdk @types/solana-txpool @types/solana-token-mints
Create a new file called index.js and add the following code to set up the client:
const { createClient } = require('solana-websocket-client');
const solanaTypes = require('@types/solana-typescript-sdk');
const TokenMints = require('@types/solana-token-mints');
// Set your Solana network and account credentials here
const SOLANA_NETWORK = 'devnet';
const ACCOUNT_ID = 'your-solana-account-id';
const PRIVATE_KEY = 'your-private-key';
// Create a new Solana client instance
async function createClient() {
const solana = require('solana-websocket-client');
return solana.connect({
network: SOLANA_NETWORK,
accounts: [
{ id: ACCOUNT_ID, pubkey: ACCOUNT_ID },
// Add your Solana account credentials here
],
keypair: {
key: PRIVATE_KEY,
path: 'path/to/your/key',
},
});
}
module.exports = createClient;
This code sets up a new Solana client instance using the connect method. You’ll need to replace SOLANA_NETWORK, ACCOUNT_ID, and PRIVATE_KEY with your actual Solana network, account ID, and private key.
Passing Strings as Bytes
Now that you have an active client instance, let’s pass a string as bytes from the client to the contract. Create a new file called contract.js and add the following code:
const { Connection } = require('@solana/web3-adapter');
// Set your Solang connection and account credentials here
const connection = new solanaWebsocketClient({
network: SOLANA_NETWORK,
accounts: [
{ id: ACCOUNT_ID, pubkey: ACCOUNT_ID },
],
});
async function mintTokens() {
const transaction = await connection.createTransaction({
authorId:ACCOUNT_ID,
maxOutputSize: 1000, // adjust the output size as needed
});
await connection.sendTransaction(transaction);
const transactionPool = await connection.getPoolTransactions();
const poolTxid = transactionPool[0].txId;
return poolTxid;
}
module.exports = mintTokens;
This code creates a new transaction and sends it to the Solang network using the client instance. It then retrieves the pool transactions for that transaction ID and returns the transaction pool transaction id.
Minting Tokens
To mint tokens from this pool transaction, you’ll need to create a function that takes an address as input, fetches the pool transaction id, creates a new transaction, and sends it to the Solang network. Create a new file called tokenMint.js and add the following code:
“`javascript
async function tokenize(minterAddress) {
const transaction = await connection.