如何覆蓋ActionLink行爲

Question

好吧，我想通過ActionLink方法爲我的網站添加一些安全性。如果用戶有足夠權限訪問動作/控制器，則ActionLink應呈現鏈接。如果沒有，它應該返回一個空字符串。現在，ActionLink是一個靜態方法，這使得它更加困難。有什麼方法可以實現我試圖做的事情嗎？

Answer 1

新AuthorizeActionLink擴展方法。根據需要超載。

public static MvcHtmlString AuthorizeActionLink(this HtmlHelper helper, string linkText, string actionName, string controllerName, object routeValues, object htmlAttributes) 
{ 
    if (HasActionPermission(helper, actionName, controllerName)) 
     return helper.ActionLink(linkText, actionName, controllerName, routeValues, htmlAttributes); 

    return MvcHtmlString.Empty; 
} 

public static MvcHtmlString AuthorizeActionLink(this HtmlHelper helper, string linkText, string actionName, string controllerName, RouteValueDictionary routeValues, IDictionary<string, object> htmlAttributes) 
{ 
    if (HasActionPermission(helper, actionName, controllerName)) 
     return helper.ActionLink(linkText, actionName, controllerName, routeValues, htmlAttributes); 

    return MvcHtmlString.Empty; 
} 

方法是做搞清楚，如果用戶被授權

static bool HasActionPermission(this HtmlHelper htmlHelper, string actionName, string controllerName) 
{ 
    ControllerBase controllerToLinkTo = string.IsNullOrEmpty(controllerName) 
     ? htmlHelper.ViewContext.Controller 
     : GetControllerByName(htmlHelper, controllerName); 

    ControllerContext controllerContext = new ControllerContext(htmlHelper.ViewContext.RequestContext, controllerToLinkTo); 
    ReflectedControllerDescriptor controllerDescriptor = new ReflectedControllerDescriptor(controllerToLinkTo.GetType()); 
    ActionDescriptor actionDescriptor = controllerDescriptor.FindAction(controllerContext, actionName); 

    return ActionIsAuthorized(controllerContext, actionDescriptor); 
} 

static bool ActionIsAuthorized(ControllerContext controllerContext, ActionDescriptor actionDescriptor) 
{ 
    if (actionDescriptor == null) 
     return false; 

    AuthorizationContext authContext = new AuthorizationContext(controllerContext, actionDescriptor); 
    foreach (IAuthorizationFilter authFilter in actionDescriptor.GetFilters().AuthorizationFilters) 
    { 
     authFilter.OnAuthorization(authContext); 

     if (authContext.Result != null) 
      return false; 
    } 

    return true; 
} 

static ControllerBase GetControllerByName(HtmlHelper helper, string controllerName) 
{ 
    IControllerFactory factory = ControllerBuilder.Current.GetControllerFactory(); 

    IController controller = factory.CreateController(helper.ViewContext.RequestContext, controllerName); 

    if (controller == null) 
    { 
     throw new InvalidOperationException(
      string.Format(
       CultureInfo.CurrentUICulture, 
       "Controller factory {0} controller {1} returned null", 
       factory.GetType(), 
       controllerName)); 
    } 

    return (ControllerBase)controller; 
}