Calc Abc2

{
  "count": 2,
  "items": [
    {
      "a_cm": 2,
      "b_cm": 2,
      "c_cm": 2,
      "citation": {
        "authors": "Kothari RU, Brott T, Broderick JP, et al.",
        "doi": "10.1161/01.STR.27.8.1304",
        "id": "kothari-1996",
        "source": "Stroke. 1996;27(8):1304-1305",
        "title": "The ABCs of measuring intracerebral hemorrhage volumes"
      },
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "formula": "abc2",
      "formula_expression": "volume_ml = (a_cm * b_cm * c_cm) / 2",
      "volume_ml": 4
    },
    {
      "a_cm": 2,
      "b_cm": 2,
      "c_cm": 2,
      "citation": {
        "authors": "Kothari RU, Brott T, Broderick JP, et al.",
        "doi": "10.1161/01.STR.27.8.1304",
        "id": "kothari-1996",
        "source": "Stroke. 1996;27(8):1304-1305",
        "title": "The ABCs of measuring intracerebral hemorrhage volumes"
      },
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "formula": "abc2",
      "formula_expression": "volume_ml = (a_cm * b_cm * c_cm) / 2",
      "volume_ml": 4
    }
  ],
  "path": "/api/calc/abc2"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://api.magentlab.com/api/calc/abc2' \
  -H 'content-type: application/json' \
  --data-raw '{"items":[{"a_cm":2,"b_cm":2,"c_cm":2},{"a_cm":2,"b_cm":2,"c_cm":2}]}'

# 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://api.magentlab.com/api/calc/abc2' \
  -H 'content-type: application/json' \
  --data-raw '{"items":[{"a_cm":2,"b_cm":2,"c_cm":2},{"a_cm":2,"b_cm":2,"c_cm":2}]}' \
  | 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 $0.007 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.007" });
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 $0.007 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.magentlab.com%2Fapi%2Fcalc%2Fabc2&method=POST
const res = await pay("https://api.magentlab.com/api/calc/abc2", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "items": [
      {
        "a_cm": 2,
        "b_cm": 2,
        "c_cm": 2
      },
      {
        "a_cm": 2,
        "b_cm": 2,
        "c_cm": 2
      }
    ]
  }),
});
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 $0.007 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.007"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://api.magentlab.com/api/calc/abc2",
        json={
            "items": [
                {
                    "a_cm": 2,
                    "b_cm": 2,
                    "c_cm": 2,
                },
                {
                    "a_cm": 2,
                    "b_cm": 2,
                    "c_cm": 2,
                },
            ],
        },
    )
    print(res.status_code, res.text)