public CanvasAuthContext([NotNull] IApplicationBindings bindings)
{
if (bindings == null)
throw FacebookApi.Nre("bindings");
if (String.IsNullOrEmpty(bindings.AppId))
throw FacebookApi.Nre("bindings.AppId");
if (String.IsNullOrEmpty(bindings.AppSecret))
throw FacebookApi.Nre("bindings.AppSecret");
if (bindings.CanvasPage == null)
throw FacebookApi.Nre("bindings.CanvasPage");
if (bindings.SiteUrl == null)
throw FacebookApi.Nre("bindings.SiteUrl");
_bindings = bindings;
}