AJAC MVC3 Request object and raw Ajax data, where the heck is it? - ajax

Question

If this was a regular post of a form I could go to Request.Form['somevalue'] and get the value. If this was a get with a query string I could go to Request.QueryString["somevalue"] and get the value.
Where is the raw data when you post an ajax request. I need a value out of the raw data string in a filter method.
Any help will be appreciated!!
Edits below:
public class ValidateAntiForgeryId : FilterAttribute, IAuthorizationFilter {
public void OnAuthorization(AuthorizationContext filterContext) {
if (filterContext == null) {
throw new ArgumentNullException("filterContext");
}
Guid filterGuid;
Guid.TryParse(filterContext.RequestContext.HttpContext.Request.Form["__sessionId"], out filterGuid);
if (filterGuid == Guid.Empty)
throw new AuthenticationException("Authentication failure");
try {
var cookieGuid = (Guid)filterContext.RequestContext.HttpContext.Items["SessionId"];
} catch {
throw new AuthenticationException("Authentication failure");
}
}
The posted data looks like this:
{"SsnLastFour":"2222","AccountNumber":"B112233","__sessionId":"dca0a504-3c40-4118-ae19-afefb9bfc8bd"}
I need access to the __sessionId chunk inside the filter.

Answer 1

There's nothing magic about AJAX posts. They're just plain old HTTP. That means you have plain old HTTP post values, and/or plainold HTTP Get values.
If you're not seeing them, it probably means you're not actually submitting them.
EDIT:
Two issues you did not include in your original question: 1) That this is JSON, and 2) That this is in an AuthorizationFilter (rather than an action method).
Both change the answers. Since ASP.NET does not natively understand JSON post values, you will have to parse them, via Request.InputStream. MVC3 by default has a JSON model binder, but AuthorizationFilters execute before model binders do, so you will be accessing things prior to the model binders being executed, and as such FormsCollection won't be populated (Request.Form[] won't work either, because as I said, asp.net doesn't natively understand JSON).
You may find that installing JSON.net via nuget may help with this task. Or you might just write a simple parse routine, since you know exactly what you're looking for.

Answer 2

You can accept the parameter values the same way you accept in normal form post.
Ex :
$.get("User/Get", { userId : "24"} ,function(data){
alert(data);
});
or
$("#yourDivId").load("User/Get?userId=23");
Your action method should look like
public ActionResult Get(int userId)
{
// you have value present in userId
if(Request.IsAjax())
{
return View("Partial/MyPartialView");
}
return View();
}
One thing you have to remember is, the parameter name of your action method should be same as of what your parameter/querystring name.

Answer 3

The fitlerContext has an ActionParameters collection which should have the parsed JSON properties (in case that helps). This may be easier than parsing the InputStream.
var sessionId = filterContext.ActionParameters["__sessionId"];