Ext.NET DirectMethod calls are failing when my site runs through CloudFlare

Question

We have a site which uses Ext.NET for its interface

Part of this interface uses Ext.NET DirectMethods to trigger c# code from a JavaScript call. For example...

c# code...

[DirectMethod]
public static void ExampleDirectMethod(string variablePassed)
{
}

js code...

var runTest = function() {
    Ext.net.DirectMethods.ExampleDirectMethod('testing', {
        success: function (result) {
            console.log((new Date()) + ' - ExampleDirectMethod - result = success');
        },
        failure: function (result) {
            console.log((new Date()) + ' - ExampleDirectMethod - result = ' + JSON.stringify(result));
        }
    });
}

This code worked fine until I set my site to run through CloudFlare

When the site is running through cloudflare, I can see the ajax calls which are triggered by my runTest() function, but instead of the result being a json string, the result is the html of the page that I am running the page from

Normal AJAX calls work fine, it's just these Ext.net.DirectMethod ones which are failing

I can't find any trace on the internet of anyone else having a similar problem

---

Update: I was able to get static DirectMethods working using the following code, but non static ones are still failing

protected override void OnPreInit(EventArgs e)
{
    if (Request.QueryString["_dc"] != null)
    {
        DirectMethodHandler handler = new DirectMethodHandler();
        handler.ProcessRequest(HttpContext.Current);
    }
}

---

Update 2: It looks like the problem is only happening with Ext.NET version 1.7 , we have tried upgrading to a newer version (2.5) and the direct methods worked through CloudFlare

---

Final Update We found the root cause of the problem. The issue is that in Ext.NET 1.7, the ext code looks for an x-ext.net header value in the requests to know whether to process the request as a DirectMethod. Cloudflare strips out all request headers with dots in them, so this is the cause of the DirectMethods not working

Cloudflare will also not allow you to set up a rule to re-add this header value back into the request

The fix is to update your c# code so that if the ?_dc= query string value exists, that you insert the x-ext.net header value back into the request before it can be processed. The values can be either delta=true or delta=true,staticmethod=true for static DirectMethods

You can detect whether a DirectMethod request is for a static one by the presence of a Request.Form["_methodName_"] value

Answer 1

https://github.com/extnet/Ext.NET

Ext.NET reached it's end-of-life on December 15, 2023 and is no longer being maintained.

The entire release history is available in the Archives and NuGet.