1 files changed, 94 insertions, 0 deletions
diff --git a/gn3/authentication.py b/gn3/authentication.py
new file mode 100644
index 0000000..baf2c7a
--- /dev/null
+++ b/gn3/authentication.py
@@ -0,0 +1,94 @@
+import functools
+import json
+import redis
+import requests
+
+from typing import Dict
+from enum import Enum, unique
+from urllib.parse import urljoin
+
+
+@functools.total_ordering
+class OrderedEnum(Enum):
+    @classmethod
+    @functools.lru_cache(None)
+    def _member_list(cls):
+        return list(cls)
+
+    def __lt__(self, other):
+        if self.__class__ is other.__class__:
+            member_list = self.__class__._member_list()
+            return member_list.index(self) < member_list.index(other)
+        return NotImplemented
+
+
+@unique
+class DataRole(OrderedEnum):
+    NO_ACCESS = "no-access"
+    VIEW = "view"
+    EDIT = "edit"
+
+
+@unique
+class AdminRole(OrderedEnum):
+    NOT_ADMIN = "not-admin"
+    EDIT_ACCESS = "edit-access"
+    EDIT_ADMINS = "edit-admins"
+
+
+def get_user_membership(conn: redis.Redis, user_id: str,
+                        group_id: str) -> Dict:
+    """Return a dictionary that indicates whether the `user_id` is a
+    member or admin of `group_id`.
+
+    Args:
+      - conn: a Redis Connection with the responses decoded.
+      - user_id: a user's unique id
+        e.g. '8ad942fe-490d-453e-bd37-56f252e41603'
+      - group_id: a group's unique id
+      e.g. '7fa95d07-0e2d-4bc5-b47c-448fdc1260b2'
+
+    Returns:
+      A dict indicating whether the user is an admin or a member of
+      the group: {"member": True, "admin": False}
+
+    """
+    results = {"member": False, "admin": False}
+    for key, value in conn.hgetall('groups').items():
+        if key == group_id:
+            group_info = json.loads(value)
+            if user_id in group_info.get("admins"):
+                results["admin"] = True
+            if user_id in group_info.get("members"):
+                results["member"] = True
+            break
+    return results
+
+
+def get_highest_user_access_role(
+        resource_id: str,
+        user_id: str,
+        gn_proxy_url: str = "http://localhost:8080") -> Dict:
+    """Get the highest access roles for a given user
+
+    Args:
+      - resource_id: The unique id of a given resource.
+      - user_id: The unique id of a given user.
+      - gn_proxy_url: The URL where gn-proxy is running.
+
+    Returns:
+      A dict indicating the highest access role the user has.
+
+    """
+    role_mapping = {}
+    for x, y in zip(DataRole, AdminRole):
+        role_mapping.update({x.value: x, })
+        role_mapping.update({y.value: y, })
+    access_role = {}
+    for key, value in json.loads(
+        requests.get(urljoin(
+            gn_proxy_url,
+            ("available?resource="
+             f"{resource_id}&user={user_id}"))).content).items():
+        access_role[key] = max(map(lambda x: role_mapping[x], value))
+    return access_role