Is this a Major Bug in C# ASP.NET Generic Handler Redundant Variables?

Question

In "C# Generic Handler", Session Variables and Input Params are becoming Duplicate or Redundant.

In C#,

if there is already a Session["X"] variable and

if input to iHttpHandler is "X", then

HttpContext.Current.Request.Params["X"] is

returning concatenated string of both Session and Input FormData from Ajax.

It is not distinguishing the difference.

I was sending data to "c# Generic Handler" from Ajax with FormData("X", "V").

Session already has the variable as "X", Say, Session["X"] is "Z";

in JS:

function f(ipaddr) {
var formData = new FormData();
formData.set("X", "V");
var url = window.location.origin + "/api/generichandlerapi.ashx";

$.ajax({
    type: 'post',
    url: url,
    data: formData,
    dataType: "json",
    success: function (response) {
          }
   });

}

Inside Handler:

string C;

Session["X"] = "Z";

C = HttpContext.Context.Request.Params["X"];

C is supposed to have only "V"

but returning

"V,Z"

Answer 1

It is expected behaviour if you use cookies for Session. When you look at the source code for HttpRequest, you can see that Cookies get added to the Params collection:

private void FillInParamsCollection() {
        _params.Add(this.QueryString);
        _params.Add(this.Form);
        _params.Add(this.Cookies);
        _params.Add(this.ServerVariables);
}