Added guests.

Backend/Auth.py

@@ -6,7 +6,7 @@ from typing import Any
 
 from fastapi import Depends, HTTPException, Request
 
-from Groups import AdminGroupName, GetGroupsForUser, IsUserInGroup
+from Groups import AdminGroupName, GetGroupsForUser, GuestGroupName, IsUserInGroup
 from Users import GetUser
 
 
@@ -14,6 +14,14 @@ ActiveSessions: dict[str, str] = {}
 
 SessionCookieName = "SaraViewSession"
 
+GuestUser: dict[str, Any] = {
+    "Username": None,
+    "IsAdmin": False,
+    "IsGuest": True,
+    "Groups": [GuestGroupName],
+    "Colour": "Purple",
+}
+
 
 def CreateSession(Username: str) -> str:
     Token = secrets.token_urlsafe(32)
@@ -25,6 +33,21 @@ def DeleteSession(Token: str) -> None:
     ActiveSessions.pop(Token, None)
 
 
+def _BuildUserRecord(Username: str, User: dict[str, Any]) -> dict[str, Any]:
+    UserGroups = GetGroupsForUser(Username)
+
+    if GuestGroupName not in UserGroups:
+        UserGroups = [*UserGroups, GuestGroupName]
+
+    return {
+        "Username": Username,
+        "IsAdmin": AdminGroupName in UserGroups,
+        "IsGuest": False,
+        "Groups": UserGroups,
+        "Colour": User.get("Colour", "Purple"),
+    }
+
+
 def GetCurrentUser(request: Request) -> dict[str, Any]:
     Token = request.cookies.get(SessionCookieName)
     Username = ActiveSessions.get(Token) if Token else None
@@ -37,14 +60,22 @@ def GetCurrentUser(request: Request) -> dict[str, Any]:
     if User is None:
         raise HTTPException(status_code=401, detail="Session user no longer exists.")
 
-    UserGroups = GetGroupsForUser(Username)
+    return _BuildUserRecord(Username, User)
 
-    return {
-        "Username": Username,
-        "IsAdmin": AdminGroupName in UserGroups,
-        "Groups": UserGroups,
-        "Colour": User.get("Colour", "Purple"),
-    }
+
+def GetCurrentUserOrGuest(request: Request) -> dict[str, Any]:
+    Token = request.cookies.get(SessionCookieName)
+    Username = ActiveSessions.get(Token) if Token else None
+
+    if Username is None:
+        return dict(GuestUser)
+
+    User = GetUser(Username)
+
+    if User is None:
+        return dict(GuestUser)
+
+    return _BuildUserRecord(Username, User)
 
 
 def RequireAdmin(CurrentUser: dict = Depends(GetCurrentUser)) -> dict: