Permissions-Based User Existence Check | Dataford Interview Questions

In a Cognite Data Fusion frontend, determine whether a user is allowed to perform one or more CRUD operations. Implement a function that returns true only when the user exists in users and has every requested operation listed in permissions.

Each user object contains a unique id. Each permission object contains a userId and an actions array. Multiple permission objects may exist for the same user, and their actions should be combined. Valid actions are create, read, update, and delete.

Formal Specification

Implement has_permissions(users, permissions, user_id, required_actions).

users is a list of objects such as {"id": "u1"}.
permissions is a list of objects such as {"userId": "u1", "actions": ["read", "update"]}.
user_id is a string.
required_actions is a non-empty list of CRUD action strings.
Return a boolean. Return false if the user does not exist or lacks any required action.

Constraints

1 <= len(users) <= 10^5
0 <= len(permissions) <= 10^5
Each user ID is unique
Permission records may contain duplicate user IDs
required_actions contains at least one action
All actions are one of create, read, update, or delete

Function Signature

def has_permissions(users, permissions, user_id, required_actions):

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