Public Finance Hash Chain

{
  "data": {
    "chargedAmount": "10031",
    "inputHash": "sha256:4eaf1d483c82d69111500df2e14ff9ae8f1e5cf3221c389f4bd78ebb5…",
    "limitations": [
      "Public or synthetic inputs only. Caller labels are declarations,…"
    ],
    "productId": "transparency-hash-chain-verification",
    "result": {
      "computedHead": {
        "digest": "0000000000000000000000000000000000000000000000000000000000000000",
        "ledgerId": "synthetic-ledger",
        "sequence": 0
      },
      "dataClass": "synthetic",
      "expectedHeadMatched": true,
      "issues": [],
      "limitations": [
        "Matches civic-ledger-1 RFC 8785 receipt digests for a safe publi…"
      ],
      "serviceId": "transparency-hash-chain-verification",
      "valid": true,
      "verifiedReceiptCount": 0
    },
    "resultHash": "sha256:59883782abf4eb2f2a69820b3b9c463cb8b7ac3dbbeafa96a7664fe67…",
    "sourceContractAmount": "38500",
    "version": "maha-legacy-adapter/1"
  },
  "proof": {
    "settlement_id": "0x00000000000000000000000000000000000000000000000000000000000000…"
  },
  "success": true
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://www.mahastrategies.com/api/v1/verify/public-finance/hash-chain' \
  -H 'content-type: application/json' \
  --data-raw '{"dataClass":"synthetic","expectedHead":{"digest":"0000000000000000000000000000000000000000000000000000000000000000","ledgerId":"synthetic-ledger","sequence":0},"preceding":{"digest":"0000000000000000000000000000000000000000000000000000000000000000","ledgerId":"synthetic-ledger","sequence":0},"publicNonpersonalRecords":true,"receipts":[]}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://www.mahastrategies.com/api/v1/verify/public-finance/hash-chain' \
  -H 'content-type: application/json' \
  --data-raw '{"dataClass":"synthetic","expectedHead":{"digest":"0000000000000000000000000000000000000000000000000000000000000000","ledgerId":"synthetic-ledger","sequence":0},"preceding":{"digest":"0000000000000000000000000000000000000000000000000000000000000000","ledgerId":"synthetic-ledger","sequence":0},"publicNonpersonalRecords":true,"receipts":[]}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.010031 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.010031" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.010031 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fwww.mahastrategies.com%2Fapi%2Fv1%2Fverify%2Fpublic-finance%2Fhash-chain&method=POST
const res = await pay("https://www.mahastrategies.com/api/v1/verify/public-finance/hash-chain", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "dataClass": "synthetic",
    "expectedHead": {
      "digest": "0000000000000000000000000000000000000000000000000000000000000000",
      "ledgerId": "synthetic-ledger",
      "sequence": 0
    },
    "preceding": {
      "digest": "0000000000000000000000000000000000000000000000000000000000000000",
      "ledgerId": "synthetic-ledger",
      "sequence": 0
    },
    "publicNonpersonalRecords": true,
    "receipts": []
  }),
});
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.010031 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.010031"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://www.mahastrategies.com/api/v1/verify/public-finance/hash-chain",
        json={
            "dataClass": "synthetic",
            "expectedHead": {
                "digest": "0000000000000000000000000000000000000000000000000000000000000000",
                "ledgerId": "synthetic-ledger",
                "sequence": 0,
            },
            "preceding": {
                "digest": "0000000000000000000000000000000000000000000000000000000000000000",
                "ledgerId": "synthetic-ledger",
                "sequence": 0,
            },
            "publicNonpersonalRecords": True,
            "receipts": [],
        },
    )
    print(res.status_code, res.text)