radionica3d/backend/services/rate_limit_service.py

import time
from session_utils import r

# Configuration
MAX_ATTEMPTS_BEFORE_CAPTCHA = 3
RATE_LIMIT_LOGIN_WINDOW = 3600  # 1 hour
MAX_LOGIN_ATTEMPTS_PER_WINDOW = 20

class RateLimitService:
    def get_login_attempts(self, email: str, ip: str) -> int:
        """Get the number of failed login attempts for this email and IP"""
        # We use a combined key to prevent distributed brute force on one account 
        # and IP-based spraying.
        count_ip = r.get(f"login_fail_ip:{ip}") or 0
        count_email = r.get(f"login_fail_email:{email}") or 0
        return max(int(count_ip), int(count_email))

    def record_failed_attempt(self, email: str, ip: str):
        """Increment failure counts for IP and Email"""
        # Increment IP failures (expires in 1 hour)
        r.incr(f"login_fail_ip:{ip}")
        r.expire(f"login_fail_ip:{ip}", RATE_LIMIT_LOGIN_WINDOW)
        
        # Increment Email failures (expires in 1 hour)
        r.incr(f"login_fail_email:{email}")
        r.expire(f"login_fail_email:{email}", RATE_LIMIT_LOGIN_WINDOW)

    def reset_attempts(self, email: str, ip: str):
        """Reset counts after successful login"""
        r.delete(f"login_fail_ip:{ip}")
        r.delete(f"login_fail_email:{email}")

    def is_captcha_required(self, email: str, ip: str) -> bool:
        """Check if captcha should be presented to the user"""
        return self.get_login_attempts(email, ip) >= MAX_ATTEMPTS_BEFORE_CAPTCHA

    def is_rate_limited(self, email: str, ip: str) -> bool:
        """Check if global rate limit for these identifiers is exceeded"""
        return self.get_login_attempts(email, ip) >= MAX_LOGIN_ATTEMPTS_PER_WINDOW

    async def verify_captcha(self, captcha_token: str) -> bool:
        """
        Stub for captcha verification logic.
        In production, this would call Google reCAPTCHA or Cloudflare Turnstile API.
        """
        if not captcha_token:
            return False
        
        # For demonstration purposes, we'll accept 'valid-captcha-token'
        # In a real app, we'd use requests.post to a verification endpoint.
        if captcha_token == "valid-captcha-token":
             return True
             
        # Verification failing for everything else for now to show the logic
        return False

    def is_order_flooding(self, email: str, ip: str) -> bool:
        """Check if user/ip is placing orders too frequently (limit: 1 per minute)"""
        if r.exists(f"order_limit_ip:{ip}") or r.exists(f"order_limit_email:{email}"):
            return True
        return False

    def record_order_placement(self, email: str, ip: str):
        """Record order placement and set 60s cooldown"""
        r.setex(f"order_limit_ip:{ip}", 60, "1")
        r.setex(f"order_limit_email:{email}", 60, "1")

rate_limit_service = RateLimitService()