binance_auth.py

"""
Binance API authentication handler.

Implements HMAC-SHA256 signature authentication for Binance API.

MIT License
Copyright (c) 2025 Pawneet Singh
"""

import hmac
import hashlib
import time
from typing import Dict

from adapter import AuthHandler
from adapter.runtime.auth import AuthType


class BinanceAuth(AuthHandler):
    """
    Binance API authentication handler.

    Uses HMAC-SHA256 signature authentication with API key and secret.
    Automatically adds timestamp and signature to requests.
    """

    def __init__(self, api_key: str, api_secret: str):
        """
        Initialize Binance authentication.

        Args:
            api_key: Binance API key
            api_secret: Binance API secret for HMAC signing
        """
        self.api_key = api_key
        self.api_secret = api_secret

    def apply(self, headers: Dict[str, str], params: Dict[str, str]) -> None:
        """
        Apply Binance authentication to the request.

        Adds:
        - X-MBX-APIKEY header with API key
        - timestamp parameter (current time in milliseconds)
        - signature parameter (HMAC-SHA256 of query string)
        """
        # Add API key to headers
        headers["X-MBX-APIKEY"] = self.api_key

        # Add timestamp to params
        timestamp = str(int(time.time() * 1000))
        params["timestamp"] = timestamp

        # Create query string and generate signature
        query_string = "&".join([f"{key}={value}" for key, value in sorted(params.items())])
        signature = hmac.new(
            self.api_secret.encode('utf-8'),
            query_string.encode('utf-8'),
            hashlib.sha256
        ).hexdigest()

        # Add signature to params
        params["signature"] = signature

    def get_type(self) -> AuthType:
        """Return API_KEY type for Binance auth."""
        return AuthType.API_KEY

    def __repr__(self) -> str:
        return "BinanceAuth(api_key='***')"