How can I supply an AntiForgeryToken when posting

Question

I am using the code as below of this post:

First I will fill an array variable with the correct values for the controller action.

Using the code below I think it should be very straightforward by just adding the following line to the JavaScript code:

data["__RequestVerificationToken"] = $('[name=__RequestVerificationToken]').val();

The <%= Html.AntiForgeryToken() %> is at its right place, and the action has a [ValidateAntiForgeryToken]

But my controller action keeps saying: "Invalid forgery token"

What am I doing wrong here?

Code

data["fiscalyear"] = fiscalyear;
data["subgeography"] = $(list).parent().find('input[name=subGeography]').val();
data["territories"] = new Array();

$(items).each(function() {
    data["territories"].push($(this).find('input[name=territory]').val());
});

    if (url != null) {
        $.ajax(
        {
            dataType: 'JSON',
            contentType: 'application/json; charset=utf-8',
            url: url,
            type: 'POST',
            context: document.body,
            data: JSON.stringify(data),
            success: function() { refresh(); }
        });
    }

Answer 1

You don't need the ValidationHttpRequestWrapper solution since MVC 4. According to this link.

1. Put the token in the headers.
2. Create a filter.
3. Put the attribute on your method.

Here is my solution:

var token = $('input[name="__RequestVerificationToken"]').val();
var headers = {};
headers['__RequestVerificationToken'] = token;
$.ajax({
    type: 'POST',
    url: '/MyTestMethod',
    contentType: 'application/json; charset=utf-8',
    headers: headers,
    data: JSON.stringify({
        Test: 'test'
    }),
    dataType: "json",
    success: function () {},
    error: function (xhr) {}
});


[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = false, Inherited = true)]
public class ValidateJsonAntiForgeryTokenAttribute : FilterAttribute, IAuthorizationFilter
{
    public void OnAuthorization(AuthorizationContext filterContext)
    {
        if (filterContext == null)
        {
            throw new ArgumentNullException("filterContext");
        }

        var httpContext = filterContext.HttpContext;
        var cookie = httpContext.Request.Cookies[AntiForgeryConfig.CookieName];
        AntiForgery.Validate(cookie != null ? cookie.Value : null, httpContext.Request.Headers["__RequestVerificationToken"]);
    }
}


[HttpPost]
[AllowAnonymous]
[ValidateJsonAntiForgeryToken]
public async Task<JsonResult> MyTestMethod(string Test)
{
    return Json(true);
}

Answer 2

I have resolved it globally with RequestHeader.

$.ajaxPrefilter(function (options, originalOptions, jqXhr) {
    if (options.type.toUpperCase() === "POST") {
        // We need to add the verificationToken to all POSTs
        if (requestVerificationTokenVariable.length > 0)
            jqXhr.setRequestHeader("__RequestVerificationToken", requestVerificationTokenVariable);
    }
});

where the requestVerificationTokenVariable is an variable string that contains the token value. Then all ajax call send the token to the server, but the default ValidateAntiForgeryTokenAttribute get the Request.Form value. I have writed and added this globalFilter that copy token from header to request.form, than i can use the default ValidateAntiForgeryTokenAttribute:

public static void RegisterGlobalFilters(GlobalFilterCollection filters)
{
      filters.Add(new GlobalAntiForgeryTokenAttribute(false));
}


public class GlobalAntiForgeryTokenAttribute : FilterAttribute, IAuthorizationFilter
{
    private readonly bool autoValidateAllPost;

    public GlobalAntiForgeryTokenAttribute(bool autoValidateAllPost)
    {
        this.autoValidateAllPost = autoValidateAllPost;
    }

    private const string RequestVerificationTokenKey = "__RequestVerificationToken";
    public void OnAuthorization(AuthorizationContext filterContext)
    {
        var req = filterContext.HttpContext.Request;
        if (req.HttpMethod.ToUpperInvariant() == "POST")
        {
            //gestione per ValidateAntiForgeryToken che gestisce solo il recupero da Request.Form (non disponibile per le chiamate ajax json)
            if (req.Form[RequestVerificationTokenKey] == null && req.IsAjaxRequest())
            {
                var token = req.Headers[RequestVerificationTokenKey];
                if (!string.IsNullOrEmpty(token))
                {
                    req.Form.SetReadOnly(false);
                    req.Form[RequestVerificationTokenKey] = token;
                    req.Form.SetReadOnly(true);
                }
            }

            if (autoValidateAllPost)
                AntiForgery.Validate();
        }
    }
}

public static class NameValueCollectionExtensions
{
    private static readonly PropertyInfo NameObjectCollectionBaseIsReadOnly = typeof(NameObjectCollectionBase).GetProperty("IsReadOnly", BindingFlags.FlattenHierarchy | BindingFlags.NonPublic | BindingFlags.Instance);

    public static void SetReadOnly(this NameValueCollection source, bool readOnly)
    {
        NameObjectCollectionBaseIsReadOnly.SetValue(source, readOnly);
    }
}

This work for me :)

Answer 3

I was just implementing this actual problem in my current project. I did it for all Ajax POSTs that needed an authenticated user.

First off, I decided to hook my jQuery Ajax calls so I do not to repeat myself too often. This JavaScript snippet ensures all ajax (post) calls will add my request validation token to the request. Note: the name __RequestVerificationToken is used by the .NET framework so I can use the standard Anti-CSRF features as shown below.

$(document).ready(function () {
    securityToken = $('[name=__RequestVerificationToken]').val();
    $('body').bind('ajaxSend', function (elm, xhr, s) {
        if (s.type == 'POST' && typeof securityToken != 'undefined') {
            if (s.data.length > 0) {
                s.data += "&__RequestVerificationToken=" + encodeURIComponent(securityToken);
            }
            else {
                s.data = "__RequestVerificationToken=" + encodeURIComponent(securityToken);
            }
        }
    });
});

In your Views where you need the token to be available to the above JavaScript code, just use the common HTML-Helper. You can basically add this code wherever you want. I placed it within a if(Request.IsAuthenticated) statement:

@Html.AntiForgeryToken() // You can provide a string as salt when needed which needs to match the one on the controller

In your controller simply use the standard ASP.NET MVC anti-CSRF mechanism. I did it like this (though I actually used a salt).

[HttpPost]
[Authorize]
[ValidateAntiForgeryToken]
public JsonResult SomeMethod(string param)
{
    // Do something
    return Json(true);
}

With Firebug or a similar tool you can easily see how your POST requests now have a __RequestVerificationToken parameter appended.

Answer 4

You can't validate an content of type contentType: 'application/json; charset=utf-8' because your date will be uploaded not in the Form property of the request, but in the InputStream property, and you will never have this Request.Form["__RequestVerificationToken"].

This will be always empty and validation will fail.

Answer 5

Check out Dixin's Blog for a great post on doing exactly that.

Also, why not use $.post instead of $.ajax?

Along with the jQuery plugin on that page, you can then do something as simple as:

        data = $.appendAntiForgeryToken(data,null);

        $.post(url, data, function() { refresh(); }, "json");

Answer 6

You won't ever have to validate an AntiForgeryToken when you receive posted JSON.

The reason is that AntiForgeryToken has been created to prevent CSRF. Since you can't post AJAX data to another host and HTML forms can't submit JSON as the request body, you don't have to protect your app against posted JSON.