extension-authorization

SKILL.md

Authorization

Authorization extendsion for Caffeine AI.

Overview

This skill adds an authentication and authorization system with role-based access control using the mixin pattern. The MixinAuthorization mixin provides standard authorization endpoints automatically.

Backend

Authentication system with role-based access control.

There is a prefabricated library mo:caffeineai-authorization/access-control.mo. It provides core authentication with role-based access control.

Module API
module {
  public type UserRole = {
    #admin;
    #user;
    #guest;
  };

  public type AccessControlState = { /* internal state */ };

  public func initState() : AccessControlState;
  public func getUserRole(state : AccessControlState, caller : Principal) : UserRole;
  public func assignRole(state : AccessControlState, caller : Principal, user : Principal, role : UserRole);
  public func isAdmin(state : AccessControlState, caller : Principal) : Bool;
  public func hasPermission(state : AccessControlState, caller : Principal, requiredRole : UserRole) : Bool;
};

Initialization is handled internally by MixinAuthorization -- do not call initialize directly. The first authenticated user to log in automatically becomes admin; no token or secret is required.

IMPORTANT: The include MixinAuthorization(accessControlState) line MUST be placed in main.mo, not in a custom mixin file.

Opting out / custom authentication

If the user asks to replace this authorization system with custom authentication (for example username/password auth, no Internet Identity, or no MixinAuthorization), remove the caffeineai-authorization mops package from the project. This is the only supported way to remove the include-authorization lint requirement, because that lint rule is shipped by the package. Do not add suppression comments or leave the package installed while omitting include MixinAuthorization(accessControlState).

When removing the package, also remove all mo:caffeineai-authorization/* imports, the accessControlState initialization, include MixinAuthorization(accessControlState), and any AccessControl guard calls that belonged to this component. Replace them with the custom authentication and authorization checks requested by the user.

Setup in main.mo

import Map "mo:core/Map";
import Principal "mo:core/Principal";
import AccessControl "mo:caffeineai-authorization/access-control";
import MixinAuthorization "mo:caffeineai-authorization/MixinAuthorization";
import Types "types";
import ProfileMixin "mixins/Profile";

actor {
  let accessControlState = AccessControl.initState();
  include MixinAuthorization(accessControlState, null);

  let userProfiles = Map.empty<Principal, Types.UserProfile>();

  include ProfileMixin(accessControlState, userProfiles);
};

Type Definitions in types.mo

module {
  public type UserProfile = {
    name : Text;
  };
};

Custom Mixin Example (mixins/Profile.mo)

The frontend requires getCallerUserProfile, saveCallerUserProfile, and getUserProfile. Pass accessControlState to your mixin so it can check permissions.

import Map "mo:core/Map";
import Principal "mo:core/Principal";
import Runtime "mo:core/Runtime";
import AccessControl "mo:caffeineai-authorization/access-control";
import Types "../types";

mixin (
  accessControlState : AccessControl.AccessControlState,
  userProfiles : Map.Map<Principal, Types.UserProfile>,
) {
  public query ({ caller }) func getCallerUserProfile() : async ?Types.UserProfile {
    if (not AccessControl.hasPermission(accessControlState, caller, #user)) {
      Runtime.trap("Unauthorized");
    };
    userProfiles.get(caller);
  };

  public shared ({ caller }) func saveCallerUserProfile(profile : Types.UserProfile) : async () {
    if (not AccessControl.hasPermission(accessControlState, caller, #user)) {
      Runtime.trap("Unauthorized");
    };
    userProfiles.add(caller, profile);
  };

  public query ({ caller }) func getUserProfile(user : Principal) : async ?Types.UserProfile {
    if (caller != user and not AccessControl.isAdmin(accessControlState, caller)) {
      Runtime.trap("Unauthorized: Can only view your own profile");
    };
    userProfiles.get(user);
  };
};

Guard Patterns

Apply the appropriate guard to every public function:

// Admin-only:
if (not AccessControl.hasPermission(accessControlState, caller, #admin)) {
  Runtime.trap("Unauthorized: Only admins can perform this action");
};

// Users only:
if (not AccessControl.hasPermission(accessControlState, caller, #user)) {
  Runtime.trap("Unauthorized: Only users can perform this action");
};

// Any user including guests: No check needed

Design Guidelines

Anonymous principals are treated as guests.

assignRole includes an admin-only guard internally.

Use shared({ caller }) for authenticated endpoints that modify data.

Use query({ caller }) for authenticated endpoints that fetch data.

Handle ownership verification where needed.

Use Runtime.trap for authorization failures.

Email Attributes

MixinAuthorization can capture the user's verified Internet Identity attributes (name and email) at sign-in. Pass a callback as the second argument instead of null; it runs once per sign-in, after the attribute bundle has been verified.

Do NOT use the mo:identity-attributes mixin directly -- always go through MixinAuthorization. The callback receives the caller principal and the verified attributes:

{
  name : ?Text;   // verified display name, when present
  email : ?Text;  // always the verified address -- sourced from II's `verified_email`, never the unverified `email` key
  sso : ?Text;    // SSO domain when the identity came from SSO, otherwise null
}

The field is named email, but it only ever holds II's verified_email value -- the unverified email key is never read. Use attrs.email in the callback (there is no attrs.verified_email field).

Store them in your own state and expose a getter to read them back:

import Map "mo:core/Map";
import Principal "mo:core/Principal";
import AccessControl "mo:caffeineai-authorization/access-control";
import MixinAuthorization "mo:caffeineai-authorization/MixinAuthorization";

actor {
  let accessControlState = AccessControl.initState();

  let emails = Map.empty<Principal, Text>();

  include MixinAuthorization(
    accessControlState,
    ?(func(caller : Principal, attrs : { name : ?Text; email : ?Text; sso : ?Text }) {
      switch (attrs.email) {
        case (?email) { emails.add(caller, email) };
        case null {};
      };
    }),
  );

  public query ({ caller }) func getCallerEmail() : async ?Text {
    emails.get(caller);
  };
};

The trusted_attribute_signers and frontend_origins canister environment variables required for attribute verification are configured automatically by the Caffeine platform -- you do not set them.

Fetching the Email on the Frontend

After sign-in, query the getter like any other authenticated actor method:

const { data: callerEmail } = useQuery<string | null>({
  queryKey: ['callerEmail'],
  queryFn: () => actor.getCallerEmail(),
  enabled: !!actor && isAuthenticated,
});

Frontend

Authentication system with role-based access control.

User Profile Setup

When using Internet Identity, the user gets a principal id only after login. Anonymous principals are treated as guests. The principal id is not human-readable -- ask the user for their name the first time they log in with a new principal.

Backend API for profiles:

getCallerUserProfile(): Promise<UserProfile | null> -- returns null if no profile exists

saveCallerUserProfile(profile: UserProfile): Promise<void> -- saves name and profile data

getUserProfile(user: Principal): Promise<UserProfile | null> -- fetch another user's profile

Rules:

On login, if the user already has a profile, do not ask for the name again

Display the user's profile name instead of the principal id

Make sure the user must be logged in before seeing any application data

When logging out, clear all cached application data including the cached user profile

Preventing Profile Setup Modal Flash

export function useGetCallerUserProfile() {
  const { actor, isFetching: actorFetching } = useActor();

  const query = useQuery<UserProfile | null>({
    queryKey: ['currentUserProfile'],
    queryFn: async () => {
      if (!actor) throw new Error('Actor not available');
      return actor.getCallerUserProfile();
    },
    enabled: !!actor && !actorFetching,
    retry: false,
  });

  return {
    ...query,
    isLoading: actorFetching || query.isLoading,
    isFetched: !!actor && query.isFetched,
  };
}

Then in your component:

const showProfileSetup = isAuthenticated && !profileLoading && isFetched && userProfile === null;

Auth State Lifecycle

The useInternetIdentity hook exposes two kinds of state — use the right one:

Scenario
loginStatus
isAuthenticated

Page load, no stored session
"idle"
false

Page load, restoring stored session
"initializing"
false → true

Stored session restored after reload
"idle"
true

Interactive login in progress (popup open)
"logging-in"
false

Interactive login just completed
"success"
true

Login popup failed / cancelled
"loginError"
false

IMPORTANT: isLoginSuccess (loginStatus === "success") is only true after an interactive login via the popup. It is NOT true when a stored identity is restored on page reload. Never use isLoginSuccess to gate authenticated vs. unauthenticated UI — always use isAuthenticated.

Key states for the login button:

isInitializing — AuthClient is loading from IndexedDB; disable the button to prevent clicks before the client is ready.

isLoggingIn — the II popup is open; disable the button to prevent duplicate popups.

Login Component

import { useInternetIdentity } from '@caffeineai/core-infrastructure';
import { useQueryClient } from '@tanstack/react-query';

export default function LoginButton() {
  const { login, clear, isAuthenticated, isInitializing, isLoggingIn } = useInternetIdentity();
  const queryClient = useQueryClient();

  const handleAuth = () => {
    if (isAuthenticated) {
      clear();
      queryClient.clear();
    } else {
      login();
    }
  };

  return (
    <button
      onClick={handleAuth}
      disabled={isInitializing || isLoggingIn}
      className={`px-6 py-2 rounded-full transition-colors font-medium ${
        isAuthenticated
          ? 'bg-gray-200 hover:bg-gray-300 text-gray-800'
          : 'bg-blue-600 hover:bg-blue-700 text-white'
      } disabled:opacity-50`}
    >
      {isInitializing ? 'Loading...' : isAuthenticated ? 'Logout' : 'Login'}
    </button>
  );
}

The login() and clear() functions are fire-and-forget (they don't return promises that track the full flow). The hook's isLoggingIn / isInitializing states track the async lifecycle — do not wrap them in local useState / isPending logic.

Gate authenticated UI on isAuthenticated (covers both fresh login and restored sessions on page reload):

{isAuthenticated ? (
  <AuthenticatedApp />
) : (
  <LoginScreen />
)}

Comparing Current User with Data Author

import { useInternetIdentity } from '@caffeineai/core-infrastructure';
import type { Principal } from '@icp-sdk/core/principal';

const { identity } = useInternetIdentity();

const isAuthor = (authorPrincipal: Principal): boolean => {
  if (!identity) return false;
  return authorPrincipal.toString() === identity.getPrincipal().toString();
};

Access Control UI

For admin-only or personal applications, show an AccessDeniedScreen component when unauthorized users try to access the application.

Error Handling

Handle authorization errors from backend Debug.trap calls gracefully in the UI with appropriate error messages shown to the user.

Note: The initialization of the first admin is done automatically in @caffeineai/core-infrastructure. The first authenticated user to log in becomes admin; no token or secret is needed.