Added core functionality

Author: vladvildanov

redis/auth/__init__.py

@@ -0,0 +1,27 @@
+from typing import Iterable
+
+
+class RequestTokenErr(Exception):
+    """
+    Represents an exception during token request.
+    """
+    def __init__(self, *args):
+        super().__init__(*args)
+
+
+class InvalidTokenSchemaErr(Exception):
+    """
+    Represents an exception related to invalid token schema.
+    """
+    def __init__(self, missing_fields: Iterable[str] = []):
+        super().__init__(
+            "Unexpected token schema. Following fields are missing: " + ", ".join(missing_fields)
+        )
+
+
+class TokenRenewalErr(Exception):
+    """
+    Represents an exception during token renewal process.
+    """
+    def __init__(self, *args):
+        super().__init__(*args)

redis/auth/err.py

@@ -0,0 +1,25 @@
+from abc import ABC, abstractmethod
+from redis.auth.token import TokenInterface
+
+"""
+This interface is the facade of an identity provider
+"""
+
+
+class IdentityProviderInterface(ABC):
+    """
+    Receive a token from the identity provider. Receiving a token only works when being authenticated.
+    """
+
+    @abstractmethod
+    def request_token(self, force_refresh=False) -> TokenInterface:
+        pass
+
+
+class IdentityProviderConfigInterface(ABC):
+    """
+    Configuration class that provides a configured identity provider.
+    """
+    @abstractmethod
+    def get_provider(self) -> IdentityProviderInterface:
+        pass

redis/auth/idp.py

@@ -0,0 +1,121 @@
+from abc import ABC, abstractmethod
+
+import jwt
+from datetime import datetime, timezone
+
+from redis.auth.err import InvalidTokenSchemaErr
+
+
+class TokenInterface(ABC):
+    @abstractmethod
+    def is_expired(self) -> bool:
+        pass
+
+    @abstractmethod
+    def ttl(self) -> float:
+        pass
+
+    @abstractmethod
+    def try_get(self, key: str) -> str:
+        pass
+
+    @abstractmethod
+    def get_value(self) -> str:
+        pass
+
+    @abstractmethod
+    def get_expires_at_ms(self) -> float:
+        pass
+
+    @abstractmethod
+    def get_received_at_ms(self) -> float:
+        pass
+
+
+class TokenResponse:
+    def __init__(self, token: TokenInterface):
+        self._token = token
+
+    def get_token(self) -> TokenInterface:
+        return self._token
+
+    def get_ttl_ms(self) -> float:
+        return self._token.get_expires_at_ms() - self._token.get_received_at_ms()
+
+
+class SimpleToken(TokenInterface):
+    def __init__(self, value: str, expires_at_ms: float, received_at_ms: float, claims: dict) -> None:
+        self.value = value
+        self.expires_at = expires_at_ms
+        self.received_at = received_at_ms
+        self.claims = claims
+
+    def ttl(self) -> float:
+        if self.expires_at == -1:
+            return -1
+
+        return self.expires_at - (datetime.now(timezone.utc).timestamp() * 1000)
+
+    def is_expired(self) -> bool:
+        if self.expires_at == -1:
+            return False
+
+        return self.ttl() <= 0
+
+    def try_get(self, key: str) -> str:
+        return self.claims.get(key)
+
+    def get_value(self) -> str:
+        return self.value
+
+    def get_expires_at_ms(self) -> float:
+        return self.expires_at
+
+    def get_received_at_ms(self) -> float:
+        return self.received_at
+
+
+class JWToken(TokenInterface):
+
+    REQUIRED_FIELDS = {'exp'}
+
+    def __init__(self, token: str):
+        self._value = token
+        self._decoded = jwt.decode(
+            self._value,
+            options={"verify_signature": False},
+            algorithms=[jwt.get_unverified_header(self._value).get('alg')]
+        )
+        self._validate_token()
+
+    def is_expired(self) -> bool:
+        exp = self._decoded['exp']
+        if exp == -1:
+            return False
+
+        return self._decoded['exp'] * 1000 <= datetime.now(timezone.utc).timestamp() * 1000
+
+    def ttl(self) -> float:
+        exp = self._decoded['exp']
+        if exp == -1:
+            return -1
+
+        return self._decoded['exp'] * 1000 - datetime.now(timezone.utc).timestamp() * 1000
+
+    def try_get(self, key: str) -> str:
+        return self._decoded.get(key)
+
+    def get_value(self) -> str:
+        return self._value
+
+    def get_expires_at_ms(self) -> float:
+        return float(self._decoded['exp'] * 1000)
+
+    def get_received_at_ms(self) -> float:
+        return datetime.now(timezone.utc).timestamp() * 1000
+
+    def _validate_token(self):
+        actual_fields = {x for x in self._decoded.keys()}
+
+        if len(self.REQUIRED_FIELDS - actual_fields) != 0:
+            raise InvalidTokenSchemaErr(self.REQUIRED_FIELDS - actual_fields)