Sending xml request to url and receiving xml response back

Question

I'm trying to send an xml request to a url and the response will also be an xml response. I know how to call a service endpoint from an MVC application but I'm not sure how to call this url and how to read what it will give me back. This is what I have so far. Is this in the right direction?

Request:

<CityStateLookupRequest USERID=”xxxxxxxx”>
<ZipCode ID="0">
<Zip5>90210</Zip5>
</ZipCode>
</CityStateLookupRequest>

Response:

<CityStateLookupResponse>
<ZipCode ID="0">
<Zip5>90210</Zip5>
<City>BEVERLY HILLS</City>
<State>CA</State>
</ZipCode>
</CityStateLookupResponse>

C# Code:

var xmlRequest = new XElement("CityStateLookupRequest",
                new XAttribute("USERID", "XXXXXXXXX"),
                new XElement("ZipCode",
                    new XAttribute("ID", "0"),
                    new XElement("Zip5", "43065")));    

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(" http://production.shippingapis.com/ShippingAPI.dll");

byte[] bytes = System.Text.Encoding.ASCII.GetBytes(xmlRequest.ToString());
request.ContentType = "text/xml; encoding='utf-8'";
request.ContentLength = bytes.Length;
request.Method = "POST";
Stream requestStream = request.GetRequestStream();
requestStream.Write(bytes, 0, bytes.Length);
requestStream.Close();
HttpWebResponse response = (HttpWebResponse)request.GetResponse();

if (response.StatusCode == HttpStatusCode.OK)
{
    var xmlDoc = new XmlDocument();

    xmlDoc.Load(response.GetResponseStream());
}

Solution

Here is one way you could do this, which is basically a form post.

var xmlRequest = new XElement("CityStateLookupRequest",
    new XAttribute("USERID", "XXXXXXXXX"),
    new XElement("ZipCode",
        new XAttribute("ID", "0"),
        new XElement("Zip5", "43065")));

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://production.shippingapis.com/ShippingAPI.dll");        

// parameters to post - other end expects API and XML parameters
var postData = new List<KeyValuePair<string, string>>();
postData.Add(new KeyValuePair<string, string>("API", "CityStateLookup"));
postData.Add(new KeyValuePair<string, string>("XML", xmlRequest.ToString()));    

// assemble the request content form encoded (reference System.Net.Http)
HttpContent content = new FormUrlEncodedContent(postData);

// indicate what we are posting in the request
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = content.Headers.ContentLength.Value;
content.CopyToAsync(request.GetRequestStream()).Wait();                        

// get response
HttpWebResponse response = (HttpWebResponse)request.GetResponse();

if (response.StatusCode == HttpStatusCode.OK)
{
    // as an xml: deserialise into your own object or parse as you wish
    var responseXml = XDocument.Load(response.GetResponseStream());
    Console.WriteLine(responseXml.ToString());
}