aboutsummaryrefslogtreecommitdiff
path: root/gn3/auth/authorisation/groups.py
blob: 6d1b1a38d6ce07a9d1643db8e842c46152f6fa9d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
"""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.authentication.users import User
from gn3.auth.dictify import register_dictifier
from gn3.auth.authentication.checks import authenticated_p

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]

register_dictifier(Group, lambda grp: {
    "group_id": grp.group_id, "group_name": grp.group_name,
    "group_metadata": grp.group_metadata})

class GroupRole(NamedTuple):
    """Class representing a role tied/belonging to a group."""
    group_role_id: UUID
    group: Group
    role: 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

@authenticated_p
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__()

@authenticated_p
@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)

@authenticated_p
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)})