import binascii
import json
import nacl.secret
import nacl.utils
import nacl.exceptions
from nacl.encoding import Base64Encoder
from . import AbstractStorage, Session
from .log import log
class NaClCookieStorage(AbstractStorage):
"""NaCl Encrypted JSON storage.
"""
def __init__(self, secret_key, *, cookie_name="AIOHTTP_SESSION",
domain=None, max_age=None, path='/',
secure=None, httponly=True,
encoder=json.dumps, decoder=json.loads):
super().__init__(cookie_name=cookie_name, domain=domain,
max_age=max_age, path=path, secure=secure,
httponly=httponly,
encoder=encoder, decoder=decoder)
self._secretbox = nacl.secret.SecretBox(secret_key)
def empty_session(self):
return Session(None, data=None, new=True, max_age=self.max_age)
async def load_session(self, request):
cookie = self.load_cookie(request)
if cookie is None:
return self.empty_session()
else:
try:
data = self._decoder(
self._secretbox.decrypt(
cookie.encode('utf-8'),
encoder=Base64Encoder).decode('utf-8')
)
return Session(None, data=data, new=False,
max_age=self.max_age)
except (binascii.Error, nacl.exceptions.CryptoError):
log.warning("Cannot decrypt cookie value, "
"create a new fresh session")
return self.empty_session()
async def save_session(self, request, response, session):
if session.empty:
return self.save_cookie(response, session._mapping,
max_age=session.max_age)
cookie_data = self._encoder(
self._get_session_data(session)
).encode('utf-8')
nonce = nacl.utils.random(nacl.secret.SecretBox.NONCE_SIZE)
self.save_cookie(
response,
self._secretbox.encrypt(cookie_data, nonce,
encoder=Base64Encoder).decode('utf-8'),
max_age=session.max_age
)
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