75 lines
2.1 KiB
Python
75 lines
2.1 KiB
Python
"""
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app/api/jwt_utils.py
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--------------------
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Thin wrappers around PyJWT for signing and verifying access tokens.
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Access tokens are short-lived JWTs (default 60 minutes) signed with
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HMAC-SHA256 using the app's SECRET_KEY. They carry only the minimum
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claims needed to identify the caller:
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{
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"sub": "42", # user.id as string
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"role": "inspector", # user.role
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"iat": 1710000000, # issued-at (UTC epoch)
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"exp": 1710003600, # expiry (UTC epoch, 60 min later)
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}
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Refresh tokens are opaque random strings stored in the DB
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(see app/models/api_token.py). This module only handles JWTs.
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"""
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import logging
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from datetime import datetime, timezone, timedelta
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import jwt
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from flask import current_app
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logger = logging.getLogger(__name__)
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ACCESS_TOKEN_LIFETIME_MINUTES = 60
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def _secret():
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return current_app.config['SECRET_KEY']
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def generate_access_token(user, lifetime_minutes: int = ACCESS_TOKEN_LIFETIME_MINUTES) -> str:
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"""
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Create and sign a new access token for the given user.
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Parameters
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----------
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user : User ORM instance
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lifetime_minutes : Token validity window (default 60 min)
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Returns
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-------
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str
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Signed JWT string ready to include in Authorization header.
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"""
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now = datetime.now(timezone.utc)
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payload = {
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'sub': str(user.id),
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'role': user.role,
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'iat': now,
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'exp': now + timedelta(minutes=lifetime_minutes),
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}
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return jwt.encode(payload, _secret(), algorithm='HS256')
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def decode_access_token(token: str) -> dict | None:
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"""
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Decode and verify a JWT access token.
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Returns the payload dict on success, or None if the token is invalid,
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expired, or tampered with. Logs the failure reason at DEBUG level.
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"""
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try:
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return jwt.decode(token, _secret(), algorithms=['HS256'])
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except jwt.ExpiredSignatureError:
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logger.debug('JWT decode failed: token expired')
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return None
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except jwt.InvalidTokenError as exc:
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logger.debug('JWT decode failed: %s', exc)
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return None
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