标签：rar 不一致 ace ado void .com names cti put
重复提交的场景很常见，可能是当时服务器延迟的原因，如购物车物品叠加，重复提交多个订单。常见的解决方法是提交后把Button在客户端Js禁用，或是用Js禁止后退键等。在ASP.NET MVC 3 Web Application中 如何去防止这类HTTP－Post的重复提交呢？ 我们可以借助Session，放置一个Token在View/Page上，然后在Server端去验证是不是同一个Token来判断此次Http-Post是否有效。看下面的代码: 首先定义一个接口，便于扩展。
public interface IPageTokenView
{
/// <summary>
/// Generates the page token.
/// </summary>
string GeneratePageToken();
/// <summary>
/// Gets the get last page token from Form
/// </summary>
string GetLastPageToken { get; }
/// <summary>
/// Gets a value indicating whether [tokens match].
/// </summary>
/// <value>
/// <c>true</c> if [tokens match]; otherwise, <c>false</c>.
/// </value>
bool TokensMatch { get; }
}
定义一个Abstract Class，包含一个
public abstract class PageTokenViewBase : IPageTokenView
{
public static readonly string HiddenTokenName = "hiddenToken";
public static readonly string SessionMyToken = "Token";
/// <summary>
/// Generates the page token.
/// </summary>
/// <returns></returns>
public abstract string GeneratePageToken();
/// <summary>
/// Gets the get last page token from Form
/// </summary>
public abstract string GetLastPageToken { get; }
/// <summary>
/// Gets a value indicating whether [tokens match].
/// </summary>
/// <value>
/// <c>true</c> if [tokens match]; otherwise, <c>false</c>.
/// </value>
public abstract bool TokensMatch { get; }
}
接着是实现SessionPageTokenView类型，记得需要在验证通过后生成新的Token，对于这个Class是把它放到Session中。
public class SessionPageTokenView : PageTokenViewBase
{
#region PageTokenViewBase
/// <summary>
/// Generates the page token.
/// </summary>
/// <returns></returns>
public override string GeneratePageToken()
{
if (HttpContext.Current.Session[SessionMyToken] != null)
{
return HttpContext.Current.Session[SessionMyToken].ToString();
}
else
{
var token = GenerateHashToken();
HttpContext.Current.Session[SessionMyToken] = token;
return token;
}
}
/// <summary>
/// Gets the get last page token from Form
/// </summary>
public override string GetLastPageToken
{
get
{
return HttpContext.Current.Request.Params[HiddenTokenName];
}
}
/// <summary>
/// Gets a value indicating whether [tokens match].
/// </summary>
/// <value>
/// <c>true</c> if [tokens match]; otherwise, <c>false</c>.
/// </value>
public override bool TokensMatch
{
get
{
string formToken = GetLastPageToken;
if (formToken != null)
{
if (formToken.Equals(GeneratePageToken()))
{
//Refresh token
HttpContext.Current.Session[SessionMyToken] = GenerateHashToken();
return true;
}
}
return false;
}
}
#endregion
#region Private Help Method
/// <summary>
/// Generates the hash token.
/// </summary>
/// <returns></returns>
private string GenerateHashToken()
{
return Utility.Encrypt(
HttpContext.Current.Session.SessionID + DateTime.Now.Ticks.ToString());
}
#endregion
这里有到一个简单的加密方法，你可以实现自己的加密方法.
public static string Encrypt(string plaintext)
{
string cl1 = plaintext;
string pwd = string.Empty;
MD5 md5 = MD5.Create();
byte[] s = md5.ComputeHash(Encoding.Unicode.GetBytes(cl1));
for (int i = 0; i < s.Length; i++)
{
pwd = pwd + s[i].ToString("X");
}
return pwd;
}
我们再来编写一个Attribute继承FilterAttribute, 实现IAuthorizationFilter接口。然后比较Form中Token与Session中是否一致，不一致就Throw Exception. Tips:这里最好使用依赖注入IPageTokenView类型，增加Logging 等机制
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
public sealed class ValidateReHttpPostTokenAttribute : FilterAttribute, IAuthorizationFilter
{
public IPageTokenView PageTokenView { get; set; }
/// <summary>
/// Initializes a new instance of the <see cref="ValidateReHttpPostTokenAttribute"/> class.
/// </summary>
public ValidateReHttpPostTokenAttribute()
{
//It would be better use DI inject it.
PageTokenView = new SessionPageTokenView();
}
/// <summary>
/// Called when authorization is required.
/// </summary>
/// <param name="filterContext">The filter context.</param>
public void OnAuthorization(AuthorizationContext filterContext)
{
if (filterContext == null)
{
throw new ArgumentNullException("filterContext");
}
if (!PageTokenView.TokensMatch)
{
//log...
throw new Exception("Invaild Http Post!");
}
}
}
还需要一个HtmlHelper的扩展方法:
public static HtmlString GenerateVerficationToken(this HtmlHelper htmlhelper)
{
string formValue = Utility.Encrypt(HttpContext.Current.Session.SessionID+DateTime.Now.Ticks.ToString());
HttpContext.Current.Session[PageTokenViewBase.SessionMyToken] = formValue;
string fieldName = PageTokenViewBase.HiddenTokenName;
TagBuilder builder = new TagBuilder("input");
builder.Attributes["type"] = "hidden";
builder.Attributes["name"] = fieldName;
builder.Attributes["value"] = formValue;
return new HtmlString(builder.ToString(TagRenderMode.SelfClosing));
}
将输出这类的HtmlString:
<input name="hiddenToken" type="hidden" value="1AB01826F590A1829E65CBD23CCE8D53" />
我们创建一个叫_ViewToken.cshtml的Partial View,这样便于模块化，让我们轻易加入到具体View里，就两行代码，第一行是扩展方法NameSpace
@using Mvc3App.Models;
@Html.GenerateVerficationToken()
假设我们这里有一个简单的Login.cshtml，然后插入其中：
<form method="post" id="form1" action="@Url.Action("Index")">
<p>
@Html.Partial("_ViewToken")
UserName:<input type="text" id="fusername" name="fusername" /><br />
Password:<input type="password" id="fpassword" name="fpassword" />
<input type="submit" value="Sign-in" />
</p>
</form>
这里我们Post的Index Action，看Controller代码，我们在Index上加上ValidateReHttpPostToken的attribute.
[HttpPost]
[ValidateReHttpPostToken]
public ActionResult Index(FormCollection formCollection)
{
return View();
}
public ActionResult Login()
{
return View();
}标签：rar 不一致 ace ado void .com names cti put
原文地址：http://www.cnblogs.com/ingstyle/p/6762132.html
