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Make payment txid replay markers permanent #46

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Merged
Iskander-Agent merged 3 commits into from
May 12, 2026
Merged

Make payment txid replay markers permanent #46

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da86999
Make payment txid replay markers permanent
slashdevcorpse May 12, 2026
ca22909
Return canonical payment txids in premium responses
slashdevcorpse May 12, 2026
5a1224a
Compact permanent replay markers
slashdevcorpse May 12, 2026
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57 changes: 43 additions & 14 deletions src/index.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -6,9 +6,9 @@ const RELAY_BASE = "https://x402-relay.aibtc.com";
const RELAY_SETTLE = `${RELAY_BASE}/settle`;
const RELAY_HEALTH = `${RELAY_BASE}/health`;
const HIRO_BASE = "https://api.hiro.so";
const REPLAY_TTL_SECONDS = 60 * 60 * 24;
const DIRECT_POLL_MAX_MS = 8000;
const DIRECT_POLL_INTERVAL_MS = 1000;
const REPLAY_MARKER_VALUE = "1";

interface PaymentRequirements {
scheme: string;
Expand Down Expand Up @@ -74,6 +74,21 @@ function b64decode<T = unknown>(s: string | null): T | null {
try { return JSON.parse(atob(s)); } catch { return null; }
}

function normalizePaymentTxid(value: unknown): string | null {
const raw = String(value || "").trim();
const hex = raw.startsWith("0x") ? raw.slice(2) : raw;
return /^[0-9a-f]{64}$/i.test(hex) ? "0x" + hex.toLowerCase() : null;
}

function normalizeSubmittedTxid(payload: any): string | null {
return normalizePaymentTxid(payload?.payload?.transaction);
}

function replayKey(txid: string): string {
const normalized = normalizePaymentTxid(txid);
return "txid:" + (normalized || txid.trim().toLowerCase());
}

function paymentRequiredResponse(req: Request, description: string, extraBody?: Record<string, unknown>): Response {
const url = new URL(req.url);
const required = buildPaymentRequired(url.toString(), description);
Expand Down Expand Up @@ -126,12 +141,10 @@ interface DirectVerifyResult {
}

async function verifyDirect(payload: any): Promise<DirectVerifyResult> {
const raw = String(payload?.payload?.transaction || "").trim();
const txidMatch = raw.match(/^0x[0-9a-f]{64}$/i);
if (!txidMatch) {
const txid = normalizeSubmittedTxid(payload);
if (!txid) {
return { success: false, reason: "invalid_txid", txid: "", raw: { hint: "payload.transaction must be 0x-prefixed 64-char hex (the txid)" } };
}
const txid = raw.toLowerCase();
const deadline = Date.now() + DIRECT_POLL_MAX_MS;
let lastTx: any = null;
while (Date.now() < deadline) {
Expand Down Expand Up @@ -257,14 +270,30 @@ async function handlePremium(req: Request, env: any, slug: string, sliceFn: (dat

const broadcastMode = String(payload?.accepted?.extra?.broadcast || "sponsored-relay");

const submittedTxid = normalizeSubmittedTxid(payload);
if (broadcastMode === "direct" && submittedTxid) {
const seen = await env.REVENUE_LOG.get(replayKey(submittedTxid));
if (seen) {
return new Response(JSON.stringify({
x402Version: 2,
error: "replay_detected",
txid: submittedTxid,
}), {
status: 409,
headers: { "content-type": "application/json", "access-control-allow-origin": "*" },
});
}
}

let outcome: { success: boolean; txid: string; payer?: string; reason?: string; held?: any; raw?: any };
if (broadcastMode === "direct") {
outcome = await verifyDirect(payload);
} else {
outcome = await settleWithRelay(payload);
}

if (!outcome.success || !outcome.txid) {
const settledTxid = normalizePaymentTxid(outcome.txid);
if (!outcome.success || !settledTxid) {
const advice = outcome.held
? "Relay queue is held for your sender (nonce desync). Switch to broadcast=direct: build a non-sponsored sBTC transfer with your own STX gas, broadcast via Hiro, then submit 0x{txid} as payload.transaction."
: broadcastMode === "direct"
Expand All @@ -273,7 +302,7 @@ async function handlePremium(req: Request, env: any, slug: string, sliceFn: (dat
return paymentRequiredResponse(req, description, {
error: "settlement_failed",
attempted_mode: broadcastMode,
reason: outcome.reason || "unknown",
reason: outcome.reason || (settledTxid ? "unknown" : "invalid_settlement_txid"),
held: outcome.held || null,
relay: broadcastMode === "sponsored-relay" ? outcome.raw : undefined,
verifier: broadcastMode === "direct" ? outcome.raw : undefined,
Expand All @@ -282,13 +311,13 @@ async function handlePremium(req: Request, env: any, slug: string, sliceFn: (dat
});
}

const txKey = "txid:" + outcome.txid;
const txKey = replayKey(settledTxid);
const seen = await env.REVENUE_LOG.get(txKey);
if (seen) {
return new Response(JSON.stringify({
x402Version: 2,
error: "replay_detected",
txid: outcome.txid,
txid: settledTxid,
}), {
status: 409,
headers: { "content-type": "application/json", "access-control-allow-origin": "*" },
Expand All @@ -307,12 +336,12 @@ async function handlePremium(req: Request, env: any, slug: string, sliceFn: (dat
const event = {
ts: new Date().toISOString(),
slug,
txid: outcome.txid,
txid: settledTxid,
payer: outcome.payer || null,
sats: Number(PRICE_SATS),
mode: broadcastMode,
};
await env.REVENUE_LOG.put(txKey, JSON.stringify(event), { expirationTtl: REPLAY_TTL_SECONDS });
await env.REVENUE_LOG.put(txKey, REPLAY_MARKER_VALUE);

const ledgerKey = "ledger:events";
const ledgerRaw = await env.REVENUE_LOG.get(ledgerKey);
Expand All @@ -322,13 +351,13 @@ async function handlePremium(req: Request, env: any, slug: string, sliceFn: (dat

const settlementResponse = {
success: true,
transaction: outcome.txid,
transaction: settledTxid,
network: NETWORK,
payer: outcome.payer || "",
};
return new Response(JSON.stringify({
...slice,
payment: { txid: outcome.txid, sats: Number(PRICE_SATS), payer: outcome.payer || null, mode: broadcastMode },
payment: { txid: settledTxid, sats: Number(PRICE_SATS), payer: outcome.payer || null, mode: broadcastMode },
}), {
status: 200,
headers: {
Expand Down Expand Up @@ -404,7 +433,7 @@ async function handleDoctor(_req: Request, env: any): Promise<Response> {
fallback_advice: "If a sponsored-relay attempt returns 402 with held=true (relay queue desynced for your sender), retry the same call as broadcast=direct. Each call's reply includes specific advice.",
revenue_ledger: ledgerStats,
notes: [
"Replay protection: each settled txid is single-use (24h TTL in KV).",
"Replay protection: each settled txid is single-use.",
"All sats settle to a dedicated service wallet — separate from any operator's main wallet.",
"Free, no-payment endpoints: /api/world/company, /api/world/customer, /api/world/premium/doctor.",
],
Expand Down