Asp.net-mvc – How to handle form submission ASP.NET MVC Back button

asp.netasp.net-mvcback-button

i have a form which allows the user to key in the data and then submit.
if everything works well on this action result, then i will redirect the user back to a thank you page.

my problem right now is that when the user click on the back button, they will be able to go back to the form page and the inputs will still be there.

and if the user just click on submit again, i will be getting some potential weird bugs.

so in terms of asp.net mvc, what's the best way to handle users who click on the back button?

thanks!

Best Answer

This solution works perfectly for both the whole controller or a specific action, simply add [NoCache]

 /// <summary>
 /// Prevent a controller or specific action from being cached in the web browser.
 /// For example - sign in, go to a secure page, sign out, click the back button.
 /// <seealso cref="https://stackoverflow.com/questions/6656476/mvc-back-button-issue/6656539#6656539"/>
 /// </summary>
public class NoCacheAttribute : ActionFilterAttribute
{
    public override void OnResultExecuting(ResultExecutingContext filterContext)
    {
        var response = filterContext.HttpContext.Response;
        response.Cache.SetExpires(DateTime.UtcNow.AddDays(-1));
        response.Cache.SetValidUntilExpires(false);
        response.Cache.SetRevalidation(HttpCacheRevalidation.AllCaches);
        response.Cache.SetCacheability(HttpCacheability.NoCache);
        response.Cache.SetNoStore();
    }
}

And in your code:

[NoCache]
[Authorize]
public class AccountController : Controller
{ ... }

Originally posted here: MVC Back button issue

Related Solutions

C# – How to RedirectToAction in ASP.NET MVC without losing request data

The solution is to use the TempData property to store the desired Request components.

For instance:

public ActionResult Send()
{
    TempData["form"] = Request.Form;
    return this.RedirectToAction(a => a.Form());
}

Then in your "Form" action you can go:

public ActionResult Form()
{
    /* Declare viewData etc. */

    if (TempData["form"] != null)
    {
        /* Cast TempData["form"] to 
        System.Collections.Specialized.NameValueCollection 
        and use it */
    }

    return View("Form", viewData);
}

Asp.net-mvc – A potentially dangerous Request.Form value was detected from the client

I think you are attacking it from the wrong angle by trying to encode all posted data.

Note that a "<" could also come from other outside sources, like a database field, a configuration, a file, a feed and so on.

Furthermore, "<" is not inherently dangerous. It's only dangerous in a specific context: when writing strings that haven't been encoded to HTML output (because of XSS).

In other contexts different sub-strings are dangerous, for example, if you write an user-provided URL into a link, the sub-string "javascript:" may be dangerous. The single quote character on the other hand is dangerous when interpolating strings in SQL queries, but perfectly safe if it is a part of a name submitted from a form or read from a database field.

The bottom line is: you can't filter random input for dangerous characters, because any character may be dangerous under the right circumstances. You should encode at the point where some specific characters may become dangerous because they cross into a different sub-language where they have special meaning. When you write a string to HTML, you should encode characters that have special meaning in HTML, using Server.HtmlEncode. If you pass a string to a dynamic SQL statement, you should encode different characters (or better, let the framework do it for you by using prepared statements or the like)..

When you are sure you HTML-encode everywhere you pass strings to HTML, then set ValidateRequest="false" in the <%@ Page ... %> directive in your .aspx file(s).

In .NET 4 you may need to do a little more. Sometimes it's necessary to also add <httpRuntime requestValidationMode="2.0" /> to web.config (reference).

Best Answer

Related Solutions

C# – How to RedirectToAction in ASP.NET MVC without losing request data

Asp.net-mvc – A potentially dangerous Request.Form value was detected from the client

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