Asynchronous versus synchronous operations

A synchronous operation returns a response after the REST API operation completes.

An asynchronous operation, such as creating an appliance backup, returns the URI of a task in the Location response header. You can use the task URI to retrieve the current status of the operation, and to obtain the associated resource once the task is complete.

  • This is common behavior for all asynchronous APIs.

  • You should not depend on any other behavior to get the current status of the operation (such as the content of the returned response body), as it varies from API to API. See the API Reference for the behavior of each specific API.

  • You should not depend on any other behavior to occur, as it is subject to change in the future, even for the same API version.

Example response header returned from an asynchronous appliance backup REST call

HTTP/1.1 202 Accepted

Date: Tue, 26 Jan 2016 23:19:14 GMT

Server: Apache

Location: https://<hostname>/rest/tasks/39CE80C4-EF2C-4717-90EA-EF166E83B49F

Content-Length: 0

cache-control: no-cache