How to modify a CORS request (from IE8 or IE9) at Server side - to enable Spring binding

Question

A client makes a CORS request using IE8 or IE9 to my domain which uses Spring 3.1 - like so.

if ($.browser.msie && window.XDomainRequest) 
{
    var xdr = new XDomainRequest();
    xdr.open("post", "http://example.com/corstest/testPost");
    xdr.onload = function() {
         var dom = new ActiveXObject("Microsoft.XMLDOM");
         dom.async = false;
         dom.loadXML(xdr.responseText);
         $("#corsdiv").html(xdr.responseText);
       };
    xdr.send("param1=abc");
    return false;                       
} 
else 
{
    $.ajax({
        url: "http://example.com/corstest/testPost",
        type: "POST",
        data: "param1=abc",
        success: function( data ) {
                $("#corsdiv").html(data);
            },
    });
    return false;
}

At server, in the controller:

@RequestMapping(value = "/testPost", method = RequestMethod.POST)
public @ResponseBody String testPost(@RequestParam Map<String,String> body, Model model, HttpServletRequest request)
{
    logger.info("Content-type: " + request.getContentType() + ";" + request.getContentLength() + ";" + request.getParameter("param1"));
    logger.info("body:" + body.toString() );
    return "Success";
}

gives the following output:

For IE9:
INFO : Content-type: null;10;null
INFO : body:{}

For Firefox:
INFO : Content-type: application/x-www-form-urlencoded; charset=UTF-8;10;abc
INFO : body:{param1=abc}

I am aware that for a IE8/9 CORS request, only text/plain is supported for the request's Content-Type header. (Reference: http://blogs.msdn.com/b/ieinternals/archive/2010/05/13/xdomainrequest-restrictions-limitations-and-workarounds.aspx) From what I understand that's the reason Spring does not bind request from IE8/IE9 - as it expects application/x-www-form-urlencoded as the Content-Type.

I used a filter to intercept requests coming in and set the ContentType to "application/x-www-form-urlencoded; charset=UTF-8" for all requests (right now for testing purposes).

Reffering to Modify request parameter with servlet filter, I wrapped the HttpServletRequest in HttpServletRequestWrapper, which overrides the getContentType, getCharacterEncoding, getHeader, getHeaderNames and getHeaders methods, and passed it to the chain.doFilter() method on a Filter.

The output I get is:

For IE9:
INFO : Content-type application/x-www-form-urlencoded; charset=UTF-8;10;null
INFO : body:{}

For Firefox:
INFO : Content-type: application/x-www-form-urlencoded; charset=UTF-8;10;abc
INFO : body:{param1=abc}

The binding does not kick in.

My question is:

1. Is it possible to get spring to bind data from the IE8/9 CORS request using this approach. If it is - what am I doing wrong?
2. If not - why, and what other options do I have to make this work?

UPDATE:

On further investigation I found that Spring binds the request data in WebRequestDatabinder using request.getParameterMap() - which I did not override in the HttpServletRequestWrapper.

The following are the conditions that must be met before post FORM data will be populated to the parameter set by the servlet container(http://java.boot.by/wcd-guide/ch01s02.html):

1. The request is an HTTP or HTTPS request.
2. The HTTP method is POST.
3. The content type is application/x-www-form-urlencoded.
4. The servlet has made an initial call of any of the 'getParameter' family of methods on the request object.

Since the servlet container sees the content-Type as text/plain, it does not parse the request body into a Parameter Map. Spring finds an empty Parameter Map and hence does not bind data.

Answer 1

I don't think Spring provides a solution out of the box. You can create a filter along the liens of this gist.