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Last active Jan 14, 2022
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Solana 101: Storing Data on the Solana Blockchain (From Figment.io's Solana 101 Course)
import {
Connection,
PublicKey,
Keypair,
SystemProgram,
Transaction,
sendAndConfirmTransaction,
} from '@solana/web3.js';
import type {NextApiRequest, NextApiResponse} from 'next';
import {getNodeURL} from '@figment-solana/lib';
import * as borsh from 'borsh';
// The state of a greeting account managed by the hello world program
class GreetingAccount {
counter = 0;
constructor(fields: {counter: number} | undefined = undefined) {
if (fields) {
this.counter = fields.counter;
}
}
}
// Borsh schema definition for greeting accounts
const GreetingSchema = new Map([
[GreetingAccount, {kind: 'struct', fields: [['counter', 'u32']]}],
]);
// The expected size of each greeting account.
const GREETING_SIZE = borsh.serialize(
GreetingSchema,
new GreetingAccount(),
).length;
type ResponseT = {
hash: string;
greeter: string;
};
export default async function greeter(
req: NextApiRequest,
res: NextApiResponse<string | ResponseT>,
) {
try {
const {network, secret, programId: programAddress} = req.body;
const url = getNodeURL(network);
const connection = new Connection(url, 'confirmed');
const programId = new PublicKey(programAddress);
const payer = Keypair.fromSecretKey(new Uint8Array(JSON.parse(secret)));
const GREETING_SEED = 'hello';
// Are there any methods from PublicKey to derive a public key from a seed?
const greetedPubkey = await PublicKey.createWithSeed(
payer.publicKey,
GREETING_SEED,
programId,
);
// This function calculates the fees we have to pay to keep the newly
// created account alive on the blockchain. We're naming it lamports because
// that is the denomination of the amount being returned by the function.
const lamports = await connection.getMinimumBalanceForRentExemption(
GREETING_SIZE,
);
// Find which instructions are expected and complete SystemProgram with
// the required arguments.
const transaction = new Transaction().add(SystemProgram.createAccountWithSeed({
fromPubkey: payer.publicKey,
basePubkey: payer.publicKey,
seed: GREETING_SEED,
newAccountPubkey: greetedPubkey,
lamports,
space: GREETING_SIZE,
programId,
}));
// Complete this function call with the expected arguments.
const hash = await sendAndConfirmTransaction(connection, transaction, [payer]);
res.status(200).json({
hash: hash,
greeter: greetedPubkey.toBase58(),
});
} catch (error) {
let errorMessage = error instanceof Error ? error.message : 'Unknown Error';
res.status(500).json(errorMessage);
}
}
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