Asp.net MVC中防止HttpPost重复提交

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; }
}

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; }

}

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

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.ToString("X");
}
return pwd;
}

[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!");
}

}
}

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));
}

<input name="hiddenToken" type="hidden" value="1AB01826F590A1829E65CBD23CCE8D53" />

@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();
}

好的，完了，由于篇幅有限,单元测试代码不贴了。让我们运行程序在IE中. 正常点击Button后提交表单，此时按F5再次提交，看到这个提示框：

[i]Invaild Http Post!