// CacheAuthorizationHandler is only attached to the CachePolicy after first time success authorization
/// <summary>
/// When output is cached, the OnAuthorization will be skipped
/// </summary>
/// <param name="context">The context</param>
/// <param name="data">The data</param>
/// <param name="validationStatus">The validation status</param>
private void CacheAuthorizationHandler(HttpContext context, object data, ref HttpValidationStatus validationStatus)
{
// when output is cached, the cachePolicy will trigger the CacheValidateHandler to authorize user
if (data == null)
{
throw new ArgumentNullException(nameof(data), "data should be AuthorizationContext");
}
AuthorizationContext filterContext = (AuthorizationContext)data;
if (filterContext == null)
{
throw new InvalidCastException("data should be AuthorizationContext");
}
AuthorizeResultEnum authorizeResult = AuthorizeUser(filterContext);
// HttpValidationStatus.Valid => return cache data
validationStatus = authorizeResult == AuthorizeResultEnum.Success ? HttpValidationStatus.Valid : HttpValidationStatus.IgnoreThisRequest;
}
/// <summary>
/// Stop processing the action and return HttpUnauthorizedResult
/// </summary>
/// <param name="filterContext">The filter context</param>
/// <param name="authorizeResult">The authorize result</param>
protected virtual void HandleUnauthorizedRequest(AuthorizationContext filterContext, AuthorizeResultEnum authorizeResult)
{
switch (authorizeResult)
{
case AuthorizeResultEnum.Failed_NotLoggedIn:
// User not logged in => redirect to login page by setting the error 401
// Owin will automatically redirect all 401 errors to login page
filterContext.Result = new HttpStatusCodeResult(HttpStatusCode.Unauthorized);
break;
case AuthorizeResultEnum.PermissionNotDefined:
ProcessUnauthorizedError(filterContext, "Permission is not defined");
break;
case AuthorizeResultEnum.Failed_SuperAdminOnly:
ProcessUnauthorizedError(filterContext, "This functionality is available for system admin only");
break;
// AuthorizeResultEnum.NotAuthorized
default:
ProcessUnauthorizedError(filterContext, $"You need to be granted permission '{this.AuthorizingPermissionId}' to access this feature. Please contact administrator for support");
break;
}
}
/// <summary>
/// Called when authorization is required.
/// </summary>
/// <param name="filterContext">The filter context</param>
/// <exception cref="System.ArgumentNullException">filterContext</exception>
/// <exception cref="System.InvalidOperationException">ActivePermissionAttribute: Cannot Use Within Child Action Cache</exception>
public void OnAuthorization(AuthorizationContext filterContext)
{
//filterContext.Controller.ControllerContext.
if (filterContext == null)
{
throw new ArgumentNullException(nameof(filterContext));
}
if (OutputCacheAttribute.IsChildActionCacheActive(filterContext))
{
// If a child action cache block is active, we need to fail immediately, even if authorization
// would have succeeded. The reason is that there's no way to hook a callback to rerun
// authorization before the fragment is served from the cache, so we can't guarantee that this
// filter will be re-run on subsequent requests.
// MvcResources.AuthorizeAttribute_CannotUseWithinChildActionCache
throw new InvalidOperationException("ActivePermissionAttribute: Cannot Use Within Child Action Cache");
}
#region Skip Authorization
/*
* Skip the authorization if
* - Controller / Action has AllowAnonymousAttribute
* - Action is NonAction
* - Action is child action
*
* */
if (filterContext.ActionDescriptor.IsDefined(typeof(AllowAnonymousAttribute), inherit: true) ||
filterContext.ActionDescriptor.IsDefined(typeof(NonActionAttribute), inherit: true) ||
filterContext.ActionDescriptor.ControllerDescriptor.IsDefined(typeof(AllowAnonymousAttribute), inherit: true))
{
return;
}
// Authorization must be done at Root action
if (filterContext.IsChildAction)
{
return;
}
#endregion Skip Authorization
AuthorizeResultEnum authorizeResult = AuthorizeUser(filterContext);
if (authorizeResult == AuthorizeResultEnum.Success)
{
// ** IMPORTANT **
// Since we're performing authorization at the action level, the authorization code runs
// after the output caching module. In the worst case this could allow an authorized user
// to cause the page to be cached, then an unauthorized user would later be served the
// cached page. We work around this by telling proxies not to cache the sensitive page,
// then we hook our custom authorization code into the caching mechanism so that we have
// the final say on whether a page should be served from the cache.
HttpCachePolicyBase cachePolicy = filterContext.HttpContext.Response.Cache;
cachePolicy.SetProxyMaxAge(new TimeSpan(0));
// add the authorization handler for cache
// data is filterContext
cachePolicy.AddValidationCallback(CacheAuthorizationHandler, filterContext);
}
else
{
HandleUnauthorizedRequest(filterContext, authorizeResult);
}
}