Remove authentication from GN3

Authentication should be handled by the auth server (gn-auth) and thus, this
commit removes code handling user authentication from the GN3 system.

1 files changed, 133 insertions, 0 deletions

diff --git a/gn3/auth/authorisation/oauth2/oauth2token.py b/gn3/auth/authorisation/oauth2/oauth2token.py
new file mode 100644
index 0000000..bb19039
--- /dev/null
+++ b/gn3/auth/authorisation/oauth2/oauth2token.py
@@ -0,0 +1,133 @@
+"""OAuth2 Token"""
+import uuid
+import datetime
+from typing import NamedTuple, Optional
+
+from pymonad.maybe import Just, Maybe, Nothing
+
+from gn3.auth import db
+
+from gn3.auth.authorisation.errors import NotFoundError
+from gn3.auth.authorisation.users import User, user_by_id
+
+from .oauth2client import client, OAuth2Client
+
+class OAuth2Token(NamedTuple):
+    """Implement Tokens for OAuth2."""
+    token_id: uuid.UUID
+    client: OAuth2Client
+    token_type: str
+    access_token: str
+    refresh_token: Optional[str]
+    scope: str
+    revoked: bool
+    issued_at: datetime.datetime
+    expires_in: int
+    user: User
+
+    @property
+    def expires_at(self) -> datetime.datetime:
+        """Return the time when the token expires."""
+        return self.issued_at + datetime.timedelta(seconds=self.expires_in)
+
+    def check_client(self, client: OAuth2Client) -> bool:# pylint: disable=[redefined-outer-name]
+        """Check whether the token is issued to given `client`."""
+        return client.client_id == self.client.client_id
+
+    def get_expires_in(self) -> int:
+        """Return the `expires_in` value for the token."""
+        return self.expires_in
+
+    def get_scope(self) -> str:
+        """Return the valid scope for the token."""
+        return self.scope
+
+    def is_expired(self) -> bool:
+        """Check whether the token is expired."""
+        return self.expires_at < datetime.datetime.now()
+
+    def is_revoked(self):
+        """Check whether the token has been revoked."""
+        return self.revoked
+
+def __token_from_resultset__(conn: db.DbConnection, rset) -> Maybe:
+    def __identity__(val):
+        return val
+    try:
+        the_user = user_by_id(conn, uuid.UUID(rset["user_id"]))
+    except NotFoundError as _nfe:
+        the_user = None
+    the_client = client(conn, uuid.UUID(rset["client_id"]), the_user)
+
+    if the_client.is_just() and bool(the_user):
+        return Just(OAuth2Token(token_id=uuid.UUID(rset["token_id"]),
+                                client=the_client.maybe(None, __identity__),
+                                token_type=rset["token_type"],
+                                access_token=rset["access_token"],
+                                refresh_token=rset["refresh_token"],
+                                scope=rset["scope"],
+                                revoked=(rset["revoked"] == 1),
+                                issued_at=datetime.datetime.fromtimestamp(
+                                    rset["issued_at"]),
+                                expires_in=rset["expires_in"],
+                                user=the_user))# type: ignore[arg-type]
+
+    return Nothing
+
+def token_by_access_token(conn: db.DbConnection, token_str: str) -> Maybe:
+    """Retrieve token by its token string"""
+    with db.cursor(conn) as cursor:
+        cursor.execute("SELECT * FROM oauth2_tokens WHERE access_token=?",
+                       (token_str,))
+        res = cursor.fetchone()
+        if res:
+            return __token_from_resultset__(conn, res)
+
+    return Nothing
+
+def token_by_refresh_token(conn: db.DbConnection, token_str: str) -> Maybe:
+    """Retrieve token by its token string"""
+    with db.cursor(conn) as cursor:
+        cursor.execute(
+            "SELECT * FROM oauth2_tokens WHERE refresh_token=?",
+            (token_str,))
+        res = cursor.fetchone()
+        if res:
+            return __token_from_resultset__(conn, res)
+
+    return Nothing
+
+def revoke_token(token: OAuth2Token) -> OAuth2Token:
+    """
+    Return a new token derived from `token` with the `revoked` field set to
+    `True`.
+    """
+    return OAuth2Token(
+        token_id=token.token_id, client=token.client,
+        token_type=token.token_type, access_token=token.access_token,
+        refresh_token=token.refresh_token, scope=token.scope, revoked=True,
+        issued_at=token.issued_at, expires_in=token.expires_in, user=token.user)
+
+def save_token(conn: db.DbConnection, token: OAuth2Token) -> None:
+    """Save/Update the token."""
+    with db.cursor(conn) as cursor:
+        cursor.execute(
+            ("INSERT INTO oauth2_tokens VALUES (:token_id, :client_id, "
+             ":token_type, :access_token, :refresh_token, :scope, :revoked, "
+             ":issued_at, :expires_in, :user_id) "
+             "ON CONFLICT (token_id) DO UPDATE SET "
+             "refresh_token=:refresh_token, revoked=:revoked, "
+             "expires_in=:expires_in "
+             "WHERE token_id=:token_id"),
+            {
+                "token_id": str(token.token_id),
+                "client_id": str(token.client.client_id),
+                "token_type": token.token_type,
+                "access_token": token.access_token,
+                "refresh_token": token.refresh_token,
+                "scope": token.scope,
+                "revoked": 1 if token.revoked else 0,
+                "issued_at": int(token.issued_at.timestamp()),
+                "expires_in": token.expires_in,
+                "user_id": str(token.user.user_id)
+            })