mirror of
https://github.com/aljazceru/python-teos.git
synced 2025-12-17 14:14:22 +01:00
118 lines
4.2 KiB
Python
118 lines
4.2 KiB
Python
from common.tools import check_compressed_pk_format
|
|
from common.cryptographer import Cryptographer
|
|
|
|
|
|
class NotEnoughSlots(ValueError):
|
|
"""Raise this when trying to subtract more slots than a user has available."""
|
|
|
|
def __init__(self, user_pk, requested_slots):
|
|
self.user_pk = user_pk
|
|
self.requested_slots = requested_slots
|
|
|
|
|
|
class IdentificationFailure(Exception):
|
|
"""
|
|
Raise this when a user can not be identified. Either the user public key cannot be recovered or the user is
|
|
not found within the registered ones.
|
|
"""
|
|
|
|
pass
|
|
|
|
|
|
class Gatekeeper:
|
|
"""
|
|
The Gatekeeper is in charge of managing the access to the tower. Only registered users are allowed to perform
|
|
actions.
|
|
|
|
Attributes:
|
|
registered_users (:obj:`dict`): a map of user_pk:appointment_slots.
|
|
"""
|
|
|
|
def __init__(self, default_slots):
|
|
self.default_slots = default_slots
|
|
self.registered_users = {}
|
|
|
|
def add_update_user(self, user_pk):
|
|
"""
|
|
Adds a new user or updates the subscription of an existing one, by adding additional slots.
|
|
|
|
Args:
|
|
user_pk(:obj:`str`): the public key that identifies the user (33-bytes hex str).
|
|
|
|
Returns:
|
|
:obj:`int`: the number of available slots in the user subscription.
|
|
"""
|
|
|
|
if not check_compressed_pk_format(user_pk):
|
|
raise ValueError("provided public key does not match expected format (33-byte hex string)")
|
|
|
|
if user_pk not in self.registered_users:
|
|
self.registered_users[user_pk] = self.default_slots
|
|
else:
|
|
self.registered_users[user_pk] += self.default_slots
|
|
|
|
return self.registered_users[user_pk]
|
|
|
|
def identify_user(self, message, signature):
|
|
"""
|
|
Checks if the provided user signature comes from a registered user.
|
|
|
|
Args:
|
|
message (:obj:`bytes`): byte representation of the original message from where the signature was generated.
|
|
signature (:obj:`str`): the user's signature (hex encoded).
|
|
|
|
Returns:
|
|
:obj:`str`: a compressed key recovered from the signature and matching a registered user.
|
|
|
|
Raises:
|
|
:obj:`<teos.gatekeeper.IdentificationFailure>`: if the user cannot be identified.
|
|
"""
|
|
|
|
if isinstance(message, bytes) and isinstance(signature, str):
|
|
rpk = Cryptographer.recover_pk(message, signature)
|
|
compressed_pk = Cryptographer.get_compressed_pk(rpk)
|
|
|
|
if compressed_pk in self.registered_users:
|
|
return compressed_pk
|
|
else:
|
|
raise IdentificationFailure("User not found.")
|
|
|
|
else:
|
|
raise IdentificationFailure("Wrong message or signature.")
|
|
|
|
def fill_slots(self, user_pk, n):
|
|
"""
|
|
Fills a given number os slots of the user subscription.
|
|
|
|
Args:
|
|
user_pk(:obj:`str`): the public key that identifies the user (33-bytes hex str).
|
|
n: the number of slots to fill.
|
|
n (:obj:`int`): the number of slots to fill.
|
|
|
|
Raises:
|
|
:obj:`<teos.gatekeeper.NotEnoughSlots>`: if the user subscription does not have enough slots.
|
|
"""
|
|
|
|
# We are not making sure the value passed is a integer, but the value is computed by the API and rounded before
|
|
# passing it to the gatekeeper.
|
|
# DISCUSS: we may want to return a different exception if teh user does not exist
|
|
if user_pk in self.registered_users and n <= self.registered_users.get(user_pk):
|
|
self.registered_users[user_pk] -= n
|
|
else:
|
|
raise NotEnoughSlots(user_pk, n)
|
|
|
|
def free_slots(self, user_pk, n):
|
|
"""
|
|
Frees some slots of a user subscription.
|
|
|
|
Args:
|
|
user_pk(:obj:`str`): the public key that identifies the user (33-bytes hex str).
|
|
n: the number of slots to free.
|
|
"""
|
|
|
|
# We are not making sure the value passed is a integer, but the value is computed by the API and rounded before
|
|
# passing it to the gatekeeper.
|
|
# DISCUSS: if the user does not exist we may want to log or return an exception.
|
|
if user_pk in self.registered_users:
|
|
self.registered_users[user_pk] += n
|