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GraphQL Authorization | GitLab Docs

Authorizations can be applied in these places:

• Types:
  • Objects (all classes descending from ::Types::BaseObject)
  • Enums (all classes descending from ::Types::BaseEnum)
• Resolvers:
  • Field resolvers (all classes descending from ::Types::BaseResolver)
  • Mutations (all classes descending from ::Types::BaseMutation)
• Fields (all fields declared using the field DSL method)

Authorizations cannot be specified for abstract types (interfaces and unions). Abstract types delegate to their member types. Basic built in scalars (such as integers) do not have authorizations.

Our authorization system uses the same DeclarativePolicy system as throughout the rest of the application.

• For single values (such as Query.project), if the currently authenticated user fails the authorization, the field resolves to null.
• For collections (such as Project.issues), the collection is filtered to exclude the objects that the user’s authorization checks failed against. This process of filtering (also known as redaction) happens after pagination, so some pages may be smaller than the requested page size, due to redacted objects being removed.

Also see authorizing resources in a mutation.

The best practice is to load only what the currently authenticated user is allowed to view with our existing finders first, without relying on authorization to filter the records. This minimizes database queries and unnecessary authorization checks of the loaded records. It also avoids situations, such as short pages, which can expose the presence of confidential resources.

See authorization_spec.rb for examples of all the authorization schemes discussed here.

Authorize a type by passing an ability to the authorize method. All fields with the same type is authorized by checking that the currently authenticated user has the required ability.

For example, the following authorization ensures that the currently authenticated user can only see projects that they have the read_project ability for (so long as the project is returned in a field that uses Types::ProjectType):

module Types
  class ProjectType < BaseObject
    authorize :read_project
  end
end

You can also authorize against multiple abilities, in which case all of the ability checks must pass.

For example, the following authorization ensures that the currently authenticated user must have read_project and another_ability abilities to see a project:

module Types
  class ProjectType < BaseObject
    authorize [:read_project, :another_ability]
  end
end

Resolvers can have their own authorizations, which can be applied either to the parent object or to the resolved values.

An example of a resolver that authorizes against the parent is Resolvers::BoardListsResolver, which requires that the parent satisfy :read_list before it runs.

An example which authorizes against the resolved resource is Resolvers::Ci::ConfigResolver, which requires that the resolved value satisfy :read_pipeline.

To authorize against the parent, the resolver must opt in (because this was not the default value initially), by declaring this with authorizes_object!:

module Resolvers
  class MyResolver < BaseResolver
    authorizes_object!

    authorize :some_permission
  end
end

To authorize against the resolved value, the resolver must apply the authorization at some point, typically by using #authorized_find!(**args):

module Resolvers
  class MyResolver < BaseResolver
    authorize :some_permission

    def resolve(**args)
      authorized_find!(**args) # calls find_object
    end

    def find_object(id:)
      MyThing.find(id)
    end
  end
end

Of the two approaches, authorizing the object is more efficient, because it helps avoid unnecessary queries.

Fields can be authorized with the authorize option.

Fields authorization is checked against the current object, and authorization happens before resolution, which means that fields do not have access to the resolved resource. If you need to apply an authorization check to a field, you probably want to add authorization to the resolver, or ideally to the type.

For example, the following authorization ensures that the authenticated user must have administrator level access to the project to view the secretName field:

module Types
  class ProjectType < BaseObject
    field :secret_name, ::GraphQL::Types::String, null: true, authorize: :owner_access
  end
end

In this example, we use field authorization (such as Ability.allowed?(current_user, :read_transactions, bank_account)) to avoid a more expensive query:

module Types
  class BankAccountType < BaseObject
    field :transactions, ::Types::TransactionType.connection_type, null: true,
      authorize: :read_transactions
  end
end

Field authorization is recommended for:

• Scalar fields (strings, booleans, or numbers) that should have different levels of access controls to other fields.
• Object and collection fields where an access check can be applied to the parent to save the field resolution, and avoid individual policy checks on each resolved object.

Field authorization does not replace object level checks, unless the object precisely matches the access level of the parent project. For example, issues can be confidential, independent of the access level of the parent. Therefore, we should not use field authorization for Project.issue.

You can also authorize fields against multiple abilities. Pass the abilities as an array instead of as a single value:

module Types
  class MyType < BaseObject
    field :hidden_field, ::GraphQL::Types::Int,
      null: true,
      authorize: [:owner_access, :another_ability]
  end
end

The field authorization on MyType.hiddenField implies the following tests:

Ability.allowed?(current_user, :owner_access, object_of_my_type) &&
    Ability.allowed?(current_user, :another_ability, object_of_my_type)

Authorizations are cumulative. In other words, the currently authenticated user may need to pass authorization requirements on both a field and a field’s type.

In the following simplified example the currently authenticated user needs both first_permission on the user and second_permission on the issue to see the author of the issue.

class UserType
  authorize :first_permission
end

class IssueType
  field :author, UserType, authorize: :second_permission
end

The combination of the object authorization on UserType and the field authorization on IssueType.author implies the following tests:

Ability.allowed?(current_user, :second_permission, issue) &&
  Ability.allowed?(current_user, :first_permission, issue.author)

In some scenarios, a given field is resolved with a dedicated resolver and the resolver takes care of checking the resolved objects’ authorization.

In such cases, especially when the field resolves a collection of objects, we’d like to skip the Type level authorization. Depending on the GraphQL query, having these overlapping authorization checks, can add significant overhead.

For such situations, we can specify which abilities should be skipped at Type level by specifying the list of abilities through skip_type_authorization on a given field. This option cascades down to all descendant fields as well.

For a real-world example, see field :discussions, Types::Notes::DiscussionType.

In that example, we have DiscussionType which specifies authorize :read_note. Discussion is composed of multiple notes of type NoteType and NoteType also specifies authorize: :read_note. Some of these notes may be system notes and may have some specific metadata of type SystemNoteMetadataType. SystemNoteMetadataType also specifies the authorize: :read_note. Each note can have emojis, which are authorized with read_emoji, which is equivalent to read_note in this case.

To represent this in a GraphQL example, we’d have following types:

class SomeType < BaseObject
  field :discussions, Types::Notes::DiscussionType.connection_type, null: true, resolver: SomeResolver
end

class DiscussionType < BaseObject
  authorize :read_note

  field :notes, Types::Notes::NoteType.connection_type, null: true
end

class NoteType < BaseObject
  authorize :read_note

  field :system_note_metadata, SystemNoteMetadataType
  field :award_emoji, AwardEmojiType
end

class SystemNoteMetadataType < BaseObject
  authorize :read_note
end

class AwardEmojiType < BaseObject
  authorize :read_emoji
end

And a query like:

query {
  someType(identified: ID) {
    discussions {
      nodes {
        notes {
          nodes {
            award_emoji {
              name
            }
          }
        }
      }
    }
  }
}

For example, if the root object of type SomeType has 10 discussions. Each of the 10 discussions have 10 notes. And the first note of each discussion has one emoji.

In this case, we authorize the discussions in SomeResolver, that is 10 authorization calls. Then when we represent each discussion with DiscussionType, we authorize each discussion object, again 10 calls. These specific calls may be fine, as these would have been cached in the request store during resolver authorization because we are authorizing the same objects. Next, we authorize each note for these 10 discussions, resulting in 10*10 = 100 authorization calls. And lastly for the first note in each discussion, we would authorize one emoji, that is another 10 calls. So in total we have 130 authorization calls:

• 10 discussions authorized in resolver
• 10 (cached) discussions authorized through DiscussionType
• 100 notes authorized through NoteType
• 10 emoji authorized through EmojiType

We can reduce these 130 calls to just 10 calls by specifying the skip_type_authorization on the discussions field. For that, SomeType definition changes to:

class SomeType < BaseObject
  field :discussions, Types::Notes::DiscussionType.connection_type, null: true, resolver: SomeResolver,
        skip_type_authorization: [:read_note, :read_emoji]
end

We can optimize the authorization calls with skip_type_authorization in this case, because:

• We already authorize the discussions in SomeResolver
• Permissions to read one note or all notes are the same for a discussion
• Permission to read a note or read an emoji are equivalent

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