Reading Form Data in ActionFilterAttribute

Question

I created an ActionFilterAttribute for my web api in order to authorize people. Getting accessToken by RequestUri is okay, however i want to send it in form data. While reading

Answer 1

It's is because the HttpContent has been read by the formatter before ActionFilter. Web API only allows reading content once. So you are unable to read it again.

Here is a possible solution to you. First, make your action parameter as FormDataCollection:

    [RequireAuthorization]
    public HttpResponseMessage PostTodo(FormDataCollection formData)
    {
        Todo todo = formData.ReadAs();
        // ...

Then, get it in ActionFilter by code:

    public override void OnActionExecuting(System.Web.Http.Controllers.HttpActionContext actionContext)
    {
        var formData = actionContext.ActionArguments["formData"] as FormDataCollection;
        if (formData != null)
        {
            var userID = formData.Get("UserID");
            var accessToken = formData.Get("AccessToken");
            // authorize
        }

        base.OnActionExecuting(actionContext);
    }