Getting the values of action parameters within an action filter

Question

I have an action that I am POSTing to from jquery:

[HttpPost] public void UpdateGroupName(int groupId, string name) {     authorisationRepository.UpdateGroupName(groupId, name); } 

This works fine with the groupId and name. I have a few other group actions so I would like to use an authorisation attribute to make sure the person performing the change has permission to make the change.

I already have an AuthorizationAttribute that retrieves the groupId successfully on GET requests by accessing filterContext.HttpContext.Request.Params["groupId"] but when it comes to POSTs it doesn't work. The Request.Form is empty and so is Request.Params.

Here's the code I have in my authorisation attribute:

public int groupId { get; set; }  protected override bool AuthorizeCore(HttpContextBase httpContext) {     username = httpContext.User.Identity.Name.Split('\\').Last();      // awesome permissions checking goes here...      return authorized;  }  public override void OnAuthorization(AuthorizationContext filterContext) {     groupId = int.Parse(filterContext.HttpContext.Request.Params["groupId"]); // this line throws an exception     base.OnAuthorization(filterContext); } 

I have looked at this answer but my Form property is empty :(

Updated to show jquery post:

var serverComm = {     post: function (url, data) {         return $.ajax({             url: url,             type: 'POST',             contentType: 'application/json; charset=utf-8',             data: JSON.stringify(data)         });     },     get: function (url, data) {         return $.ajax({             url: url,             type: 'GET',             cache: false,             contentType: 'application/json; charset=utf-8',             data: data         });     } }; // some awesome code later... serverComm.post(editGroupNameUrl, { groupId: group.id, name: newName }) 

Answer 1

The reason your code doesn't work is because you are sending your request as a JSON string. So there are no request parameters in the POST body and you cannot fetch them in the Request.Params.

So instead of:

filterContext.HttpContext.Request.Params["groupId"] 

use:

filterContext.Controller.ValueProvider.GetValue("groupId").AttemptedValue 

This will query the value provider (in your case the JsonValueProvider) to obtain the corresponding value send by the client.

Answer 2

Try without the stringify. I guess MVC is understanding another way of binding besides the request parameter -> action parameter. I guess it's understanding the json posted. JQuery, if you pass just the data object (without stringify) will post each field as a request parameter (at least, I think so). It's easy to try :)