server-verwaltung/app/utils.py
nocci 5b676d2a2c feat(forms): add parsing and validation for price, RAM, and storage
- introduce parsing helpers for decimal, RAM, and storage values
- convert form input types from number to text for flexibility
- parse RAM and storage with optional units for better user input handling
2025-12-06 14:16:39 +00:00

126 lines
3.4 KiB
Python

import base64
import hashlib
import os
import secrets
import re
from typing import Optional
from cryptography.fernet import Fernet, InvalidToken
from starlette.requests import Request
# Optional symmetric encryption for management passwords
_ENC_KEY = os.getenv("ENCRYPTION_KEY")
_f = None
if _ENC_KEY:
try:
key_str = _ENC_KEY.strip()
# Accept either a full Fernet key or derive one from an arbitrary passphrase.
if len(key_str) >= 44 and key_str.endswith("="):
fernet_key = key_str.encode()
else:
digest = hashlib.sha256(key_str.encode("utf-8")).digest()
fernet_key = base64.urlsafe_b64encode(digest)
_f = Fernet(fernet_key)
except Exception:
_f = None
def can_encrypt() -> bool:
"""Return True if an encryption key has been configured."""
return _f is not None
def encrypt_secret(plaintext: str) -> Optional[str]:
"""Encrypt a secret string using Fernet, if configured."""
if not plaintext or not _f:
return None
token = _f.encrypt(plaintext.encode("utf-8"))
return token.decode("utf-8")
def decrypt_secret(token: str) -> Optional[str]:
"""Decrypt a Fernet-encrypted token, returning a string or None."""
if not token or not _f:
return None
try:
plaintext = _f.decrypt(token.encode("utf-8"))
return plaintext.decode("utf-8")
except (InvalidToken, ValueError):
return None
# ----- Parsing helpers -----
def parse_decimal(value: str) -> Optional[float]:
"""Parse a decimal number allowing comma or dot."""
if not value:
return None
try:
normalized = value.replace(",", ".").strip()
return float(normalized)
except ValueError:
return None
def parse_ram_mb(value: str) -> Optional[int]:
"""
Parse RAM with optional unit (MB/GB/TB). Defaults to GB if a unit is missing.
Returns MB.
"""
if not value:
return None
v = value.strip().lower()
match = re.match(r"([0-9]+(?:[\\.,][0-9]+)?)(tb|gb|mb)?", v)
if not match:
return None
number = float(match.group(1).replace(",", "."))
unit = match.group(2) or "gb"
if unit == "tb":
return int(number * 1024 * 1024)
if unit == "gb":
return int(number * 1024)
return int(number)
def parse_storage_gb(value: str) -> Optional[int]:
"""
Parse storage with optional unit (GB/TB). Defaults to GB.
Returns GB.
"""
if not value:
return None
v = value.strip().lower()
match = re.match(r"([0-9]+(?:[\\.,][0-9]+)?)(tb|gb)?", v)
if not match:
return None
number = float(match.group(1).replace(",", "."))
unit = match.group(2) or "gb"
if unit == "tb":
return int(number * 1024)
return int(number)
# ----- CSRF helpers -----
_CSRF_SESSION_KEY = "csrf_token"
def ensure_csrf_token(request: Request) -> str:
"""
Ensure the current session has a CSRF token and return it.
"""
token = request.session.get(_CSRF_SESSION_KEY)
if not token:
token = secrets.token_urlsafe(32)
request.session[_CSRF_SESSION_KEY] = token
return token
def validate_csrf(request: Request, token: str) -> bool:
"""
Compare provided token with the one stored in the session.
"""
stored = request.session.get(_CSRF_SESSION_KEY)
if not stored or not token:
return False
return secrets.compare_digest(str(stored), str(token))