Creating an MVC Controller Proxy for a Web API Controller

Question

I have an MVC project that is exposed externally. I have an internal Web API project.

For reasons beyond my control, I cannot expose the Web API project directly and I cannot add Web API Controllers to my MVC project.

I need to create an MVC Controller that will act as a proxy for a Web API Controller. I need the response from the MVC Controller to look as if the Web API was called directly.

What is the best way to accomplish this?

Is there a better approach than what I have so far?

How can I fix the error that I am getting?

Here is what I have so far:

MyMVCController

[HttpGet]
public HttpResponseMessage GetData(HttpRequestMessage request)
 {
 ...
 var response = proxy.GetData();
 return request.CreateResponse();
 }

MyProxyClass

public HttpResponseMessage GetData()
 {
 ...
 return HttpRequest(new HttpRequestMessage(HttpMethod.Get, uri));
 }
private HttpResponseMessage HttpRequest(HttpRequestMessage message)
 {
 HttpResponseMessage response;
 ...
 using (var client = new HttpClient())
 {
 client.Timeout = TimeSpan.FromSeconds(120);
 response = client.SendAsync(message).Result;
 }
 return response;
 }

In the MVC Controller, I am getting an InvalidOperationException on the request.CreateResponse() line. The error says:

The request does not have an associated configuration object or the provided configuration was null.

Any help would be greatly appreciated. I have searched Google and StackOverflow but I haven't been able to find a good solution for creating this proxy between MVC and Web API.

Thanks!

Answer 1

You can do it by just creating some JsonResult action in your controller which will return result of calling web API.

public class HomeController : Controller
{
 public async Task<JsonResult> CallToWebApi()
 {
 return this.Content(
 await new WebApiCaller().GetObjectsAsync(),
 "application/json"
 );
 }
}
public class WebApiCaller
{
 readonly string uri = "your url";
 public async Task<string> GetObjectsAsync()
 {
 using (HttpClient httpClient = new HttpClient())
 {
 return await httpClient.GetStringAsync(uri);
 }
 }
}

• jkruer01: Wouldn't that always return a 200 status code? I need to preserve whatever status code of the response from the Web API. Also, I don't want the Web API to serialize the object, the proxy de-serialize it, and then the MVC serialize the object again.
• aleha_84: you could always return status code you want base on result you achieve from web api call
• jkruer01: what about the serialize, de-serialize, serialize again issue?
• jkruer01: Also, what would happen if the Web Api returned an error message/response. The WebApiCaller would try to deserialize it into the expected object type which would then throw an error right?
• aleha_84: modified. Withou deserialization. For details look here: stackoverflow.com/a/9777889/1235390