How to return GetResponseStream in xml?

Question

I am trying to create web request, which sends XML via POST call and would like to return the response back in XML.

I am having a little difficulty with the response back xml, as I am little I unsure how do I set that up int he code below. here is my attempt:

      // Attempt to receive the WebResponse to the WebRequest.
            using (HttpWebResponse hwresponse = (HttpWebResponse)hwrequest.GetResponse())
            {
                statusCode = (int)hwresponse.StatusCode;
                if (hwresponse != null)
                { // If we have valid WebResponse then read it.
                    using (StreamReader reader = new StreamReader(hwresponse.GetResponseStream()))
                    {
                        // XPathDocument doc = new XPathDocument(reader);
                        string responseString = reader.ReadToEnd();
                        if (statusCode == 201 )
                        {

                          //  var response = new XElement("Status",
                           //    new XElement("status_code", statusCode),
                          //     new XElement("resources_created",
                          ////         new XElement("Link"),
                          //         new XElement("href"),
                          //         new XElement("title")
                          //         ),

                          //         new XElement("warnings")

                           //        );

                            XmlDocument xmlDoc = new XmlDocument();
                            xmlDoc.Load(responseString);
                            XmlNodeList address = xmlDoc.GetElementsByTagName("Status");

                            responseData = xmlDoc.ToString();
                            reader.Close();

                        }
                    }
                }

                hwresponse.Close();

            }

        }
        catch (WebException e)
        {
            if (e.Status == WebExceptionStatus.ProtocolError)
            {
               // XmlDocument xmlDoc = new XmlDocument();
              //  XmlNodeList address = xmlDoc.GetElementsByTagName("Status", statusCode);
               // xmlDoc.Load(xmlDoc);
            }



         //   if (e.Status == WebExceptionStatus.ProtocolError)
         //   {
              //  responseData = "Status Code : {0}" + ((HttpWebResponse)e.Response).StatusCode + "Status Description : {0}" + ((HttpWebResponse)e.Response).StatusDescription;
                // responseData "Status Description : {0}" + ((HttpWebResponse)e.Response).StatusDescription;


           // }
        }

I would like to be able to return the response back in the following XML format:

<status>
<status_code>201</status_code>
<etag>12345678</etag>
<resources_created>
    <link 
        rel="http://api-info.com" 
        href="http://api-info.com/tag/Some%20Tag" 
        title="Subscriber Tag (Some Tag)" />
</resources_created>
<warnings>
    <warning>Some Warning Message</warning>
</warnings>
</status>

I would also like to ask, if my 'StatusCode' should be setup as if conditions or try&catch.
Any guide would be most helpful. Many thanks.

Answer 1

Yes, you should handle the response status (200, 201, 404 etc.) using If/Else statements and NOT rely on try/catch to handle your logic. Try/Catch is for error handling, and not a place to handle regular application flow.

For the Web Requests you are using an obsolete API. Unless there is a specific limitation that forces you to use HttpWebRequest and HttpWebResponse, you should use a newer (and simpler) API like WebClient or HttpClient (only .NET 4.5).

http://msdn.microsoft.com/en-us/library/system.net.webclient%28v=vs.110%29.aspx http://msdn.microsoft.com/en-us/library/system.net.http.httpclient%28v=vs.118%29.aspx

For response handling i would advice using Linq to XML instead of the old XmlDocument API.

If your response XML has the "status" element at the root of the XML document, then you can do:

var xmlDoc = XDocument.Load(reader);
var statusXml = xmlDoc.ToString();

If the "status" element is a children of another root XML element, then you can do:

var xmlDoc = XDocument.Load(reader);
var statusElement = xmlDoc.Root.Element("status");
var statusXml = statusElement.ToString();

If you still want to use the old HTTP API, You can get rid of

string responseString = reader.ReadToEnd();

and pass directly the StreamReader in the XDocument.Load method as in my example.

In case you upgrade your solution to use e.g. WebClient you can use the DownloadString() method, and then load the string result into the XDocument.Load() method.

Answer 2

You may not have any control over what is sent to you but you can ask for xml with an Accept header.

hwrequest.Accept = "application/xml";

However, you will have no control over the structure.