Authorizing your functions

By default, Celest Functions are deny-by-default, meaning only you as the author and administrator of your project can access them.

To change the access level, you can use one of the following annotations:

• @public — Grants access to anyone on the Internet, making your function publicly accessible.
• @authenticated — Grants access to only authenticated users. (Requires Celest Auth)

Authenticated functions

When using Celest Auth, you have the ability to restrict access to your functions to only authenticated users. This is done by adding the @authenticated annotation to your function.

import 'package:celest/celest.dart';
 
@cloud
@authenticated
Future<String> sayHello() async {
  return 'Hello, valued customer!';
}

Accessing user information

To get the calling user's information, you can use the @principal annotation in your function.

import 'package:celest/celest.dart';
 
@cloud
@authenticated
Future<String> sayHello({
  @principal required User user,
}) async {
  return 'Hello, ${user.displayName}!';
}

In fact, you can do this for @public functions, too, since in that case there may be a user that Celest knows about. For these cases, the User parameter must be nullable to account for both scenarios.

@cloud
@authenticated
Future<String> sayHello({
  // User can be required here since it's `@authenticated`
  @principal required User user,
}) async {
  return 'Hello, ${user.displayName}!';
}
 
@cloud
@public
Future<String> sayHello({
  // User must be nullable here for `@public` functions
  @principal User? user,
}) async {
  if (user == null) {
	  return 'Hello, stranger!';
  }
  return 'Hello, ${user.displayName}!';
}