SP Tried to perform SingleLogout received an error "HTTP Form does not contain SAMLRequest"

Question

I took this sample test SP code from ItFoxTec and perform a SingleLogout from this controller:

[Route("SingleLogout")]
public async Task<IActionResult> SingleLogout()
{
    Saml2StatusCodes status;
    var requestBinding = new Saml2PostBinding();
    var logoutRequest = new Saml2LogoutRequest(config, User);
    try
    {
        requestBinding.Unbind(Request.ToGenericHttpRequest(), logoutRequest);
        status = Saml2StatusCodes.Success;
        await logoutRequest.DeleteSession(HttpContext);
    }
    catch (Exception exc)
    {
        // log exception
        Debug.WriteLine("SingleLogout error: " + exc);
        status = Saml2StatusCodes.RequestDenied;
    }

    var responsebinding = new Saml2PostBinding();
    responsebinding.RelayState = requestBinding.RelayState;
    var saml2LogoutResponse = new Saml2LogoutResponse(config)
    {
        InResponseToAsString = logoutRequest.IdAsString,
        Status = status
    };
    return responsebinding.Bind(saml2LogoutResponse).ToActionResult();
}

As I hit this endpoint, My IDP occured an error with message:

HTTP Form does not contain SAMLRequest

It seems the error occured on Saml2BindingException

Am I did a misconfiguration in IdP or SP? Thank you.

Answer 1

The SP initiate logout by calling the Logout method.

The SingleLogout method is called from the IdP to do single logout initiated by the IdP or another SP.