To correctly perform all the steps for logout, your logout page needs contextual information about the user’s session and the client that initiated logout request. This information is provided by the LogoutRequest class and will provide your logout page data needed for the logout workflow.
The logout page can be triggered in different ways:
If the login page is being triggered by a protocol workflow, then this means Duende IdentityServer has redirected the user’s browser to the logout page. In these scenarios, a logoutId parameter will be passed that represents the logout context. The logoutId value can be exchanged with the GetLogoutContextAsync API on the interaction service obtain a LogoutRequest object.
If the page is directly accessed by the user then there will be no logoutId parameter, but the context can still be accessed by calling GetLogoutContextAsync just without passing any parameters.
In either case, the LogoutRequest contains the data to perform client notification, and redirect the user back to the client after logout.