# Permissions

Django OAuth Toolkit provides a few utility classes to use along with other permissions in Django REST Framework, so you can easily add scoped-based permission checks to your API views.

More details on how to add custom permissions to your API Endpoints can be found at the official Django REST Framework documentation

## TokenHasScope

The TokenHasScope permission class allows access only when the current access token has been authorized for all the scopes listed in the required_scopes field of the view.

For example:

    class SongView(views.APIView):
        authentication_classes = [OAuth2Authentication]
        permission_classes = [TokenHasScope]
        required_scopes = ['music']

The required_scopes attribute is mandatory.

## TokenHasReadWriteScope

The TokenHasReadWriteScope permission class allows access based on the READ_SCOPE and WRITE_SCOPE configured in the settings.

When the current request’s method is one of the “safe” methods GET, HEAD, OPTIONS the access is allowed only if the access token has been authorized for the READ_SCOPE scope. When the request’s method is one of POST, PUT, PATCH, DELETE the access is allowed if the access token has been authorized for the WRITE_SCOPE.

The required_scopes attribute is optional and can be used by other scopes needed in the view.

For example:

    class SongView(views.APIView):
        authentication_classes = [OAuth2Authentication]
        permission_classes = [TokenHasReadWriteScope]
        required_scopes = ['music']

When a request is performed both the READ_SCOPE \ WRITE_SCOPE and ‘music’ scopes are required to be authorized for the current access token.

## TokenHasResourceScope

The TokenHasResourceScope permission class allows access only when the current access token has been authorized for all the scopes listed in the required_scopes field of the view but according of request’s method.

When the current request’s method is one of the “safe” methods, the access is allowed only if the access token has been authorized for the scope:read scope (for example music:read). When the request’s method is one of “non safe” methods, the access is allowed only if the access token has been authorized for the scope:write scope (for example music:write).

    class SongView(views.APIView):
        authentication_classes = [OAuth2Authentication]
        permission_classes = [TokenHasResourceScope]
        required_scopes = ['music']

The required_scopes attribute is mandatory (you just need inform the resource scope).

## IsAuthenticatedOrTokenHasScope

The IsAuthenticatedOrTokenHasScope permission class allows access only when the current access token has been authorized for all the scopes listed in the required_scopes field of the view but according to the request’s method. It also allows access to Authenticated users who are authenticated in django, but were not authenticated through the OAuth2Authentication class. This allows for protection of the API using scopes, but still let’s users browse the full browsable API. To restrict users to only browse the parts of the browsable API they should be allowed to see, you can combine this with the DjangoModelPermission or the DjangoObjectPermission.

For example:

    class SongView(views.APIView):
        permission_classes = [IsAuthenticatedOrTokenHasScope, DjangoModelPermission]
        required_scopes = ['music']

The required_scopes attribute is mandatory.

## TokenMatchesOASRequirements

The TokenMatchesOASRequirements permission class allows the access based on a per-method basis and with alternative lists of required scopes. This permission provides full functionality required by REST API specifications like the OpenAPI Specification (OAS) security requirement object.

The required_alternate_scopes attribute is a required map keyed by HTTP method name where each value is a list of alternative lists of required scopes.

In the follow example GET requires “read” scope, POST requires either “create” scope OR “post” and “widget” scopes, etc.

    class SongView(views.APIView):
        authentication_classes = [OAuth2Authentication]
        permission_classes = [TokenMatchesOASRequirements]
        required_alternate_scopes = {
            "GET": [["read"]],
            "POST": [["create"], ["post", "widget"]],
            "PUT":  [["update"], ["put", "widget"]],
            "DELETE": [["delete"], ["scope2", "scope3"]],
        }

The following is a minimal OAS declaration that shows the same required alternate scopes. It is complete enough to try it in the swagger editor.

    openapi: "3.0.0"
    info:
      title: songs
      version: v1
    components:
      securitySchemes:
        song_auth:
          type: oauth2
          flows:
            implicit:
              authorizationUrl: http://localhost:8000/o/authorize
              scopes:
                read: read about a song
                create: create a new song
                update: update an existing song
                delete: delete a song
                post: create a new song
                widget: widget scope
                scope2: scope too
                scope3: another scope
    paths:
      /songs:
        get:
          security:
            - song_auth: [read]
          responses:
            '200':
              description: A list of songs.
        post:
          security:
            - song_auth: [create]
            - song_auth: [post, widget]
          responses:
            '201':
              description: new song added
        put:
          security:
            - song_auth: [update]
            - song_auth: [put, widget]
          responses:
            '204':
              description: song updated
        delete:
          security:
            - song_auth: [delete]
            - song_auth: [scope2, scope3]
          responses:
            '200':
              description: song deleted