MVC扩展Filter,通过继承ActionFilterAttribute为登录密码加密

港控/mmm° 2021-10-15 10:39 143阅读 0赞

与ActionFilter相关的接口有2个：

□ IActionFilter 对action执行前后处理

void OnActionExecuting(ActionExecutingContext filterContext);  
可以在此对请求处理，甚至开启一个新的请求。

void OnActionExecuted(ActonExecutedContext filterContext);  
可以在此对返回结果处理，甚至取消返回结果。

关于参数ActionExecutingContext和ActonExecutedContext共有的：  
都继承于ControllerContext。  
都有ActionDescriptor属性：提供了action的细节  
都有ActionResult属性：当设置为null的时候取消整个请求

关于ActonExecutedContext独有的：  
Canceled属性：bool类型，ActionExecutedContext是否被其它action filter取消  
Exception属性：action filter和action抛出的异常  
ExceptionHandled属性：bool类型，异常是否被处理

□ IResultFilter 对action返回结果前后做处理

方法与属性与IActionFilter类似。  
void OnResultExecuted(ResultExecutedContext filterContext);  
void OnResultExecuting(ResultExecutingContext filterContext);

实例：继承ActionFilterAttribute为登录密码加密

ActionFilterAttribute包含了如下4个方法：  
void OnActionExecuting(ActionExecutingContext filterContext);  
void OnActionExecuted(ActonExecutedContext filterContext);  
void OnResultExecuted(ResultExecutedContext filterContext);  
void OnResultExecuting(ResultExecutingContext filterContext);  
所以，我们可以在派生类中重写这4个方法。

□ 思路

→在执行action之前对密码加密  
→在执行action之后，根据是否登录成功，来决定返回成功或重新登录视图  
→在action返回结果之后，再追加一些内容

□ 继承ActionFilterAttribute

using System;

using System.Security.Cryptography;

using System.Text;

using System.Web.Mvc;

using System.Web.Security;

namespace MvcApplication1.Extension

{

public class EncryptLoginAttribute : ActionFilterAttribute

{

private string username;

private string password;

private bool isAuthorized = false;

private string longdate;

private string lastTry;

public override void OnActionExecuting(ActionExecutingContext filterContext)

{

username = filterContext.HttpContext.Request.Form["username"];

password = filterContext.HttpContext.Request.Form["password"];

MD5 md5Hash = MD5.Create();

string md5Password = GetMD5Hash(md5Hash, password);

bool result = Membership.ValidateUser(username, md5Password);

if (result)

{

FormsAuthentication.SetAuthCookie(username, false);

isAuthorized = true;

longdate = DateTime.Now.ToLongDateString();

}

else

{

isAuthorized = false;

lastTry = DateTime.Now.ToShortDateString() + "-" + DateTime.Now.ToShortTimeString();

}

public override void OnActionExecuted(ActionExecutedContext filterContext)

{

if (isAuthorized)

{

filterContext.Result = new ViewResult(){ViewName = "Welcome"};

}

else

{

ViewResult result = new ViewResult();

result.ViewName = "Index";

result.ViewBag.message = "Login fail";

filterContext.Result = result;

}

public override void OnResultExecuted(ResultExecutedContext filterContext)

{

if (filterContext.Exception == null && !filterContext.Canceled)

{

ViewResult result = (ViewResult)filterContext.Result;

if (result != null)

{

if (result.ViewName == "Welcome")

{

filterContext.HttpContext.Response.Write("<p style='color:Green;'><br/>Today is "

+ longdate + "<br/></p>");

}

else if (result.ViewName == "Index")

{

filterContext.HttpContext.Response.Write("<p style='color:Red;'><br />Last Login attemp at "+lastTry+"<br/></p>");

}

filterContext.Result = result;

}

private static string GetMD5Hash(MD5 md5Hash, string input)

{

//string→byte[]

byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));

StringBuilder stringBuilder = new StringBuilder();

foreach (byte b in data)

{

stringBuilder.Append(b.ToString("x2"));

}

return stringBuilder.ToString();

}

□ HomeController

using System.Web.Mvc;

using System.Web.Security;

using MvcApplication1.Extension;

namespace MvcApplication1.Controllers

{

public class HomeController : Controller

{

public ActionResult Index()

{

return View();

}

[HttpPost]

[EncryptLogin]

public ActionResult Login(string username, string password)

{

//TODO:保存到数据库

return null;

}

public ActionResult SignOut()

{

FormsAuthentication.SignOut();

return RedirectToAction("Index");

}

□ Home/Index.cshtml为登录页

ViewBag.Title = "Index";

Layout = "~/Views/Shared/_Layout.cshtml";

}

<h2>Index</h2>

<p style="color: red;">@ViewBag.message</p>

@using (Html.BeginForm("Login", "Home", FormMethod.Post, new {id = "loginForm"}))

{

<p>

用户名：@Html.TextBox("username", null, new {style = "width:100px"})

</p>

<p>

密码： @Html.Password("password", null, new {style = "width: 100px"})

</p>

<p>

</p>

}

□ web.config相关配置

□ 登录成功视图：/Shared/Welcome.cshtml

@\{  
    ViewBag.Title = "Welcome";  
    Layout = "~/Views/Shared/\_Layout.cshtml";  
\}

<h2>登录成功~~</h2>  
@Html.ActionLink("登出","SignOut","Home")

登录页：

[![1][]][1 1]

登录失败：

[![3][]][3 1]

□ 如果想在全局使用

filters.Add(new EncryptLoginAttribute());

□ 备注

暂没有把登录成功显示页面调试出来，因为，当使用FormsAuthentication.Authenticate(username, md5Password)时，提示此方法已经过时；而使用Membership.ValidateUser(username, md5Password)时，对应的Web.config如何配置，暂没细究。

参考资料：  
[MVC Filters Part 3 - Action Filter and Action Result Filter][]

转载于:https://www.cnblogs.com/darrenji/p/3754713.html

[1]: /images/20211015/1ee16fb7d9254aa492d21185242a1ae0.png
[1 1]: https://images0.cnblogs.com/blog/417212/201405/271112044319644.png
[3]: /images/20211015/71f20cd13b624025b7c51b5971fc4e14.png
[3 1]: https://images0.cnblogs.com/blog/417212/201405/271112050565287.png
[MVC Filters Part 3 - Action Filter and Action Result Filter]: http://ernarendrashrestha.blogspot.com/2014/02/mvc-filters-part-3-action-filter-and.html