Making an async HttpClient post request with data from FormCollection

Question

I am doing an Asp.Net MVC 4 project and am looking to an internal request (like a proxy) to our api service.

This is what the index method looks like in my controller. I'm stuck at the PostAsync part.

[HttpPost]
public async Task<ActionResult> Index(FormCollection body){

   HttpClient httpClient  = new HttpClient();
   httpClient.BaseAddress = new Uri("http://myapi.com");

   // posts to http://myapi.com/users
   var response = await httpClient.PostAsync("users", body);

   if(response.isSuccessStatusCode) return Json(new {
        status = true,
        url    = response.Content.Url
   });
}

I want to pass my "application/x-form-urlencoded" "body" content to the PostAsync POST method. However, I get an error reading "body is not of type HttpContent".

I can't cast or convert. What now?

Let me know what I'm doing incorrectly here.

Erik

Untutored

FormCollection and HttpContent are completely different types. Why would you expect that your code would work (with or without a cast)? What you need to do is to create a new HttpContent, based on the data in your FormCollection. – Doronicum

Right, Im trying to illustrate what I need done above. I'm looking for more of a walk-through than a simple answer. @svick, do you have an examples of creating a new HttpContent based on a FormCollection set of data? – Untutored

Answer 1

I'm not entirely sure what you're trying to do, but possibly converting the FormCollection to a dictionary and using the FormUrlEncodedContent class is what you're looking for.

e.g.:

var response = await httpClient.PostAsync("users",
                                          new FormUrlEncodedContent(
                                              body.
                                                  AllKeys.ToDictionary(
                                                      k => k, v => body[v])));

Trig

All this time, I was trying to do this using MultipartFormDataContent and failing. Simply using FormUrlEncodedContent with my request works like a charm. Thanks! – Bathtub

is it not better to convert the data to HttpContent? or is HttpContent just another dictionary? – Untutored

@Untutored I think HttpContent is an abstract base class. You cannot instantiate that. Instead, u need a concrete class .. which inherits that .. and FormUrlEncodedContent i think is one of those :) – Chromic

Yes, HttpContent is abstract, you need to use one of the concrete classes like ByteArrayContent, FormUrlEncodedContent, etc... – Trig

@Untutored FormUrlEncodedContent is an HttpContent, see MSDN: msdn.microsoft.com/en-us/library/… public class FormUrlEncodedContent : ByteArrayContent and public class ByteArrayContent : HttpContent – Canales