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"""Handle the management of resource/user groups."""
import json
from uuid import UUID, uuid4
from typing import Any, Sequence, Iterable, Optional, NamedTuple
from flask import g
from pymonad.maybe import Just, Maybe, Nothing
from gn3.auth import db
from gn3.auth.dictify import dictify
from gn3.auth.authentication.users import User
from .checks import authorised_p
from .privileges import Privilege
from .errors import AuthorisationError
from .roles import (
Role, create_role, revoke_user_role_by_name, assign_user_role_by_name)
class Group(NamedTuple):
"""Class representing a group."""
group_id: UUID
group_name: str
group_metadata: dict[str, Any]
def dictify(self):
"""Return a dict representation of `Group` objects."""
return {
"group_id": self.group_id, "group_name": self.group_name,
"group_metadata": self.group_metadata
}
class GroupRole(NamedTuple):
"""Class representing a role tied/belonging to a group."""
group_role_id: UUID
group: Group
role: Role
def dictify(self) -> dict[str, Any]:
"""Return a dict representation of `GroupRole` objects."""
return {
"group_role_id": self.group_role_id, "group": dictify(self.group),
"role": dictify(self.role)
}
class GroupCreationError(AuthorisationError):
"""Raised whenever a group creation fails"""
class MembershipError(AuthorisationError):
"""Raised when there is an error with a user's membership to a group."""
def __init__(self, user: User, groups: Sequence[Group]):
"""Initialise the `MembershipError` exception object."""
groups_str = ", ".join(group.group_name for group in groups)
error_message = (
f"User '{user.name} ({user.email})' is a member of {len(groups)} "
f"groups ({groups_str})")
super().__init__(f"{type(self).__name__}: {error_message}.")
def user_membership(conn: db.DbConnection, user: User) -> Sequence[Group]:
"""Returns all the groups that a member belongs to"""
query = (
"SELECT groups.group_id, group_name, groups.group_metadata "
"FROM group_users INNER JOIN groups "
"ON group_users.group_id=groups.group_id "
"WHERE group_users.user_id=?")
with db.cursor(conn) as cursor:
cursor.execute(query, (str(user.user_id),))
groups = tuple(Group(row[0], row[1], json.loads(row[2]))
for row in cursor.fetchall())
return groups
def create_group(
conn: db.DbConnection, group_name: str, group_leader: User,
group_description: Optional[str] = None) -> Group:
"""Create a new group."""
user_groups = user_membership(conn, group_leader)
if len(user_groups) > 0:
raise MembershipError(group_leader, user_groups)
@authorised_p(
("system:group:create-group",), (
"You do not have the appropriate privileges to enable you to "
"create a new group."),
group_leader)
def __create_group__():
with db.cursor(conn) as cursor:
new_group = __save_group__(
cursor, group_name,(
{"group_description": group_description}
if group_description else {}))
add_user_to_group(cursor, new_group, group_leader)
revoke_user_role_by_name(cursor, group_leader, "group-creator")
assign_user_role_by_name(cursor, group_leader, "group-leader")
return new_group
return __create_group__()
@authorised_p(("group:role:create-role",),
error_message="Could not create the group role")
def create_group_role(
conn: db.DbConnection, group: Group, role_name: str,
privileges: Iterable[Privilege]) -> GroupRole:
"""Create a role attached to a group."""
with db.cursor(conn) as cursor:
group_role_id = uuid4()
role = create_role(cursor, role_name, privileges)
cursor.execute(
("INSERT INTO group_roles(group_role_id, group_id, role_id) "
"VALUES(?, ?, ?)"),
(str(group_role_id), str(group.group_id), str(role.role_id)))
return GroupRole(group_role_id, group, role)
def authenticated_user_group(conn) -> Maybe:
"""
Returns the currently authenticated user's group.
Look into returning a Maybe object.
"""
user = g.user
with db.cursor(conn) as cursor:
cursor.execute(
("SELECT groups.* FROM group_users "
"INNER JOIN groups ON group_users.group_id=groups.group_id "
"WHERE group_users.user_id = ?"),
(str(user.user_id),))
groups = tuple(Group(UUID(row[0]), row[1], json.loads(row[2] or "{}"))
for row in cursor.fetchall())
if len(groups) > 1:
raise MembershipError(user, groups)
if len(groups) == 1:
return Just(groups[0])
return Nothing
def user_group(cursor: db.DbCursor, user: User) -> Maybe[Group]:
"""Returns the given user's group"""
cursor.execute(
("SELECT groups.group_id, groups.group_name, groups.group_metadata "
"FROM group_users "
"INNER JOIN groups ON group_users.group_id=groups.group_id "
"WHERE group_users.user_id = ?"),
(str(user.user_id),))
groups = tuple(
Group(UUID(row[0]), row[1], json.loads(row[2] or "{}"))
for row in cursor.fetchall())
if len(groups) > 1:
raise MembershipError(user, groups)
if len(groups) == 1:
return Just(groups[0])
return Nothing
def is_group_leader(cursor: db.DbCursor, user: User, group: Group):
"""Check whether the given `user` is the leader of `group`."""
ugroup = user_group(cursor, user).maybe(
False, lambda val: val) # type: ignore[arg-type, misc]
if not group:
# User cannot be a group leader if not a member of ANY group
return False
if not ugroup == group:
# User cannot be a group leader if not a member of THIS group
return False
cursor.execute(
("SELECT roles.role_name FROM user_roles LEFT JOIN roles "
"ON user_roles.role_id = roles.role_id WHERE user_id = ?"),
(str(user.user_id),))
role_names = tuple(row[0] for row in cursor.fetchall())
return "group-leader" in role_names
def all_groups(conn: db.DbConnection) -> Maybe[Sequence[Group]]:
"""Retrieve all existing groups"""
with db.cursor(conn) as cursor:
cursor.execute("SELECT * FROM groups")
res = cursor.fetchall()
if res:
return Just(tuple(
Group(row["group_id"], row["group_name"],
json.loads(row["group_metadata"])) for row in res))
return Nothing
def __save_group__(
cursor: db.DbCursor, group_name: str,
group_metadata: dict[str, Any]) -> Group:
"""Save a group to db"""
the_group = Group(uuid4(), group_name, group_metadata)
cursor.execute(
("INSERT INTO groups "
"VALUES(:group_id, :group_name, :group_metadata) "
"ON CONFLICT (group_id) DO UPDATE SET "
"group_name=:group_name, group_metadata=:group_metadata"),
{"group_id": str(the_group.group_id), "group_name": the_group.group_name,
"group_metadata": json.dumps(the_group.group_metadata)})
return the_group
def add_user_to_group(cursor: db.DbCursor, the_group: Group, user: User):
"""Add `user` to `the_group` as a member."""
cursor.execute(
("INSERT INTO group_users VALUES (:group_id, :user_id) "
"ON CONFLICT (group_id, user_id) DO NOTHING"),
{"group_id": str(the_group.group_id), "user_id": str(user.user_id)})
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