Method: courses.posts.getAddOnContext

Gets metadata for Classroom add-ons in the context of a specific post.

To maintain the integrity of its own data and permissions model, an add-on should call this to validate query parameters and the requesting user's role whenever the add-on is opened in an iframe.

This method returns the following error codes:

  • PERMISSION_DENIED for access errors.
  • INVALID_ARGUMENT if the request is malformed.
  • NOT_FOUND if one of the identified resources does not exist.

HTTP request


The URL uses gRPC Transcoding syntax.

Path parameters



Required. Identifier of the course.



Optional. Deprecated, use itemId instead.

Query parameters



Identifier of the announcement, courseWork, or courseWorkMaterial under which the attachment is attached. This field is required, but is not marked as such while we are migrating from postId.



Optional. Token that authorizes the request.

The token is passed as a query parameter when the user is redirected from Classroom to the add-on's URL.

The authorization token is required when neither of the following is true:

  • The add-on has attachments on the post.
  • The developer project issuing the request is the same project that created the post.

Request body

The request body must be empty.

Response body

If successful, the response body contains an instance of AddOnContext.

Authorization scopes

Requires one of the following OAuth scopes:


For more information, see the Authorization guide.