兌換交易¶

import time, requests

quote = requests.post(
    "https://api.testnet.sera.cx/api/v1/swap/quote",
    json={
        "from_token":    "0x965d4b...d0e",    # USDC address
        "to_token":      "0xef64d1...40f",    # EURC address
        "from_amount":   "1000000000",      # 1000 USDC（6 位小數）
        "owner_address": "0xYOUR_WALLET",
        "recipient":     "0xYOUR_WALLET",   # 接收輸出代幣的地址（可以是另一個錢包）
        "expiration":    int(time.time()) + 3600,
        "gas_mode":      "receive_less",
    },
    timeout=10,
).json()
# quote["uuid"]           — 唯一報價識別碼
# quote["route_params"]   — 需要簽名的 EIP-712 參數
# quote["fee_breakdown"]  — Gas 費用詳情（gas_cost_usd、gas_cost_from_token）

from eth_account import Account
from eth_account.messages import encode_typed_data

DOMAIN = {
    "name": "Sera",
    "version": "1",
    "chainId": 11155111,                                              # Sepolia
    "verifyingContract": "0x83475A1bD98a8DC2DCd507A747e4DC85da241D6e",
}

INTENT_TYPES = {
    "Intent": [
        {"name": "taker",                "type": "address"},
        {"name": "inputToken",           "type": "address"},
        {"name": "outputToken",          "type": "address"},
        {"name": "maxInputAmount",       "type": "uint256"},
        {"name": "minOutputAmount",      "type": "uint256"},
        {"name": "recipient",            "type": "address"},
        {"name": "initialDepositAmount", "type": "uint256"},
        {"name": "uuid",                 "type": "uint256"},
        {"name": "deadline",             "type": "uint48"},
    ]
}

signable  = encode_typed_data(DOMAIN, INTENT_TYPES, quote["route_params"])
signature = Account.from_key(PRIVATE_KEY).sign_message(signable).signature.hex()

import json
from pathlib import Path

submit_body = {"uuid": quote["uuid"], "signature": "0x" + signature.removeprefix("0x")}
permit = quote.get("permit") or {}
if permit.get("permit_required") and permit.get("permit_supported"):
    typed = permit["eip712"]
    permit_message = encode_typed_data(typed["domain"], typed["types"], typed["message"])
    permit_sig = Account.from_key(PRIVATE_KEY).sign_message(permit_message).signature.hex()
    submit_body["permit_signature"] = "0x" + permit_sig.removeprefix("0x")
    submit_body["permit_deadline"] = int(typed["message"]["deadline"])
elif permit.get("permit_required") and int(permit["current_allowance_raw"]) < int(permit["value_raw"]):
    raise RuntimeError("Approve the quoted spender, confirm the transaction, then request a fresh quote")

journal = Path("swap-requests")
journal.mkdir(mode=0o700, exist_ok=True)
# hex gives an opaque quote ID a filename without interpreting path separators.
saved_path = journal / (quote["uuid"].encode().hex() + ".json")
with saved_path.open("x", encoding="utf-8") as saved:
    json.dump(submit_body, saved)
response = requests.post("https://api.testnet.sera.cx/api/v1/swap",
                         json=submit_body, timeout=10)
response.raise_for_status()
swap = response.json()
# Accepted is not chain-confirmed: track trade_id via the authenticated order API.