Question

I have a jquery routine that calls an MVC action which will do a PUT/POST to an API url. The call from jQuery is fine and works as well as the call to the API using C#. A response is received from the API in JSON format when checked via Firebug/Fiddler.

How do i get that response to be sent back to the calling jQuery?

My C# code is:

 public string callAPIPut(string ApiUrl, string JsonString)
    {
        WebRequest request = WebRequest.Create(ApiUrl);

        ASCIIEncoding encoding = new ASCIIEncoding();
        byte[] data = encoding.GetBytes(JsonString);

        request.ContentType = "application/json; charset=utf-8";
        request.Method = WebRequestMethods.Http.Put;
        request.ContentLength = JsonString.Length;

        Stream newStream = request.GetRequestStream();
        newStream.Write(data, 0, JsonString.Length);
        newStream.Close();

        return ""; // How do I return the JSON response from the API?
    }

When doing a GET i could use something like the following to get the response back to the calling jQuery:

response = (HttpWebResponse)request.GetResponse();
using (StreamReader sr = new StreamReader(response.GetResponseStream()))
{
   serviceResponse = sr.ReadToEnd();
}
return serviceResponse;

I dont know how to return the response when doing a Put/Post?

Answer 1

public ActionResult CallAPIPut(string ApiUrl, string JsonString)
{
    using (var client = new WebClient())
    {
        client.Headers[HttpRequestHeader.ContentType] = "application/json";
        byte[] data = Encoding.Default.GetBytes(JsonString);
        byte[] result = client.UploadData(ApiUrl, "PUT", data);
        return Content(Encoding.Default.GetString(result), "application/json");
    }
}

or make it more intelligently, by wrapping in a custom and reusable action result to avoid cluttering your controller with infrastructure plumbing:

public class ApiResult : ActionResult
{
    public ApiResult(string apiUrl, string jsonData)
        : this(apiUrl, jsonData, "PUT")
    {
    }

    public ApiResult(string apiUrl, string jsonData, string method)
    {
        ApiUrl = apiUrl;
        JsonData = jsonData;
        Method = method;
    }


    public string ApiUrl { get; private set; }
    public string JsonData { get; private set; }
    public string Method { get; set; }

    public override void ExecuteResult(ControllerContext context)
    {
        var response = context.HttpContext.Response;
        var contentType = "application/json";
        response.ContentType = contentType;
        using (var client = new WebClient())
        {
            client.Headers[HttpRequestHeader.ContentType] = contentType;
            byte[] data = Encoding.Default.GetBytes(JsonData);
            byte[] result = client.UploadData(ApiUrl, Method, data);
            response.Write(Encoding.Default.GetString(result));
        }
    }
}

and now your controller action simply becomes:

public ActionResult CallAPIPut(string apiUrl, string jsonString)
{
    return new ApiResult(apiUrl, jsonString);
}