vvzvlad
54 lines
1.5 KiB
Python
54 lines
1.5 KiB
Python
import hashlib
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import hmac
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import secrets
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import os
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from config import get_settings
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Config = get_settings()
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class KeyManager:
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SECRET_FILE = "data/media_digest.key"
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signing_key = None
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@classmethod
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def get_or_create_signing_key(cls) -> str:
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"""
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Get existing signing key from memory, secret file or generate a new one
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"""
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if cls.signing_key is not None:
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return cls.signing_key
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if os.path.exists(cls.SECRET_FILE):
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with open(cls.SECRET_FILE, 'r', encoding='utf-8') as f:
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cls.signing_key = f.read().strip()
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return cls.signing_key
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cls.signing_key = secrets.token_hex(32) # Generate new key if file doesn't exist
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with open(cls.SECRET_FILE, 'w', encoding='utf-8') as f:
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f.write(cls.signing_key) # Save to file
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return cls.signing_key
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def generate_media_digest(url: str) -> str:
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"""
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Generate short HMAC digest (first 8 chars) for media URL using SHA1
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"""
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signing_key = KeyManager.get_or_create_signing_key()
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message = url.encode('utf-8')
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key = signing_key.encode('utf-8')
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signature = hmac.new(key, message, hashlib.sha1)
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return signature.hexdigest()[:8]
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def verify_media_digest(url: str, digest: str | None) -> bool:
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"""
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Verify HMAC digest for media URL
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Returns True if digest is valid
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"""
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if not digest:
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return False
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expected = generate_media_digest(url)
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return hmac.compare_digest(expected, digest)
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