What we built, and how to use it.

import {Transaction, sendAndConfirmTransaction} from "@solana/web3.js";
import {newChannelId, openChannelInstruction, usd} from "@dinara/sdk";

const {instruction, channel} = openChannelInstruction({
  owner: owner.publicKey,
  mint,                    // the test dollar
  ownerToken,              // the owner's token account
  id: newChannelId(),
  deposit: usd(100),
  ceiling: usd(40),        // never more than the deposit
  expiresAt: Math.floor(Date.now() / 1000) + 24 * 3600,
  agent: agentPublicKey,
  operator,                // optional: may settle at once; without one, settlement goes through the dispute window
  label: "Research agent",
  payees: [inference, search, transcribe],
});

const tx = new Transaction().add(instruction);
await sendAndConfirmTransaction(connection, tx, [owner]);

import {fetchChannel, MeterSession, payingFetch} from "@dinara/sdk";

const terms = await fetchChannel(connection, channel);
if (!terms) throw new Error("No channel at that address");
const session = new MeterSession(terms, agentSecretKey);

// A 402 is answered once, with a voucher for exactly the quoted price.
const url = "https://api.example.com/v1/complete";
const res = await payingFetch(session, url, {method: "POST", body}, {
  maxPrice: 50_000n, // refuse any quote above $0.05
});

session.latest; // the newest signed state: all a settlement needs

import {PublicKey} from "@solana/web3.js";
import {
  fetchChannel, HEADERS, paymentRequired, verifyPayment,
} from "@dinara/sdk";

const wallet = new PublicKey(PAYEE_WALLET);
const price = 2_500n; // $0.0025
let previous: {seq: bigint; owed: bigint} | null = null;
let newest: string | null = null;

export async function POST(request: Request) {
  const voucher = request.headers.get(HEADERS.voucher);
  const address = request.headers.get(HEADERS.channel);
  const channel = address
    ? await fetchChannel(connection, new PublicKey(address))
    : null;
  const check = channel
    ? verifyPayment({voucher, channel, payee: wallet, price, previous, trustedOperators: [DINARA_OPERATOR]})
    : null;
  if (!check?.ok) {
    return paymentRequired({payee: wallet, price, memo: "1k tokens"});
  }

  newest = voucher; // all you need to be paid at settlement
  previous = {seq: check.voucher.state.seq, owed: check.owed};
  return Response.json(await complete(request));
}

import {Transaction, sendAndConfirmTransaction} from "@solana/web3.js";
import {
  decodeVoucher, fetchReceipt, receiptAddress, settleInstructions,
} from "@dinara/sdk";

const signed = decodeVoucher(newestVoucher)!; // the agent's newest
const tx = new Transaction().add(
  ...settleInstructions({
    settler: operator.publicKey,
    channel,
    owner,
    mint,
    ownerToken,              // where the unused deposit returns
    agent,
    signed,
    payeeTokens,             // one token account per state line, in order
  }),
);
await sendAndConfirmTransaction(connection, tx, [operator]);

const receipt = await fetchReceipt(connection, receiptAddress(channel));