WCF service to get an atom feed

Question

I am very new to programming and my first task is to create a WCF service that will take an ATOM feed and expose it to my application. Now, I've read up on XML serialization and syndication but it doesn't seem to be what I need in my (lack of) experience.

Here is a snippet of the feed. It's generated by a seedlist spi

<atom:generator version="1.2" lconn:version="4.5.0.0">
Seedlist Service Backend System</atom:generator>
<wplc:timestamp isPartial="false">AAABQtdnfpE=</wplc:timestamp>
<atom:category term="ContentSourceType/Wikis" scheme="com.ibm.wplc.taxonomy://feature_taxonomy" 
label="Wikis"/>
<atom:title>Wikis : 0 entries of Seedlist WIKIS</atom:title>
<atom:updated>2013-12-09T13:49:13+01:00</atom:updated>

Do I need to create objects for all these elements?

And what about these wplc elements?

<wplc:action do="update"/>
<wplc:fieldInfo id="FIELD_ENTRY_TYPE" name="item type" 
description="item type - page, file or wiki" type="string" 
contentSearchable="false" fieldSearchable="true" 
parametric="false" returnable="true" sortable="false" 
supportsExactMatch="false"/>
<wplc:fieldInfo id="FIELD_TAG" name="Tag" 
description="Document tag" type="string" 
contentSearchable="true" fieldSearchable="true" 
parametric="false" returnable="true" sortable="false" 
supportsExactMatch="true"/>

All the examples, tutorials and explanations I find are of simple xml files So can I just use XML Reader to achieve this? And if so, I need some help.

Here is a sample WCF I found:

public class Service1 : IService1
    {
        public string GetData(string value)
        {
            WebRequest request = WebRequest.Create("http://wheremyxmlis/file.xml");
            WebResponse response = request.GetResponse();
            Stream dataStream = response.GetResponseStream();
            XmlReader reader = XmlReader.Create("http://wheremyxmlis/file.xml");
        reader = new XmlTextReader("http://wheremyxmlis.xml");

        try
        {


            reader = new XmlTextReader("http://wheremyxmlis/file.xml");



            while (reader.Read())
            {
                switch (reader.NodeType)
                {
                    case XmlNodeType.Element:
                        Console.Write("<{0}>", reader.Name);
                        break;
                    case XmlNodeType.Text:
                        Console.Write(reader.Value);
                        break;
                    case XmlNodeType.CDATA:
                        Console.Write("<![CDATA[{0}]]>", reader.Value);
                        break;
                    case XmlNodeType.ProcessingInstruction:
                        Console.Write("<?{0} {1}?>", reader.Name, reader.Value);
                        break;
                    case XmlNodeType.Comment:
                        Console.Write("<!--{0}-->", reader.Value);
                        break;
                    case XmlNodeType.XmlDeclaration:
                        Console.Write("<?xml version='1.0'?>");
                        break;
                    case XmlNodeType.Document:
                        break;
                    case XmlNodeType.DocumentType:
                        Console.Write("<!DOCTYPE {0} [{1}]", reader.Name, reader.Value);
                        break;
                    case XmlNodeType.EntityReference:
                        Console.Write(reader.Name);
                        break;
                    case XmlNodeType.EndElement:
                        Console.Write("</{0}>", reader.Name);
                        break;
                }
            }
        }

        finally
        {
            if (reader != null)
                reader.Close();


            response.Close();

Answer 1

This is the solution I managed to come up with and it works!

This is just a class file added to the WCF Service library

public class Item
{
    public string Link { get; set; }
    public string Title { get; set; }
    public string Content { get; set; }
    public string Author { get; set; }          
    public DateTime Updated { get; set; }
    public string FeedType { get; set; }

    public string Tag { get; set; }
    public Item()
    {
        //Link = ""; 
        //Title = "";
        //Name = "";                            
        //Content = "";
        //Updated = DateTime.Today;
        //    FeedType = FeedType.RSS;
    }
}

/// <summary>
/// A simple RSS, RDF and ATOM feed parser.
/// </summary>
public class FeedParser
{
    /// <summary>
    /// Parses the given <see cref="FeedType"/> and returns a <see cref="IList&amp;lt;Item&amp;gt;"/>.
    /// </summary>
    /// <returns></returns>
    public IList<Item> Parse(XDocument doc, string feedType)
    {
        switch (feedType)
        {
            case "RSS":
                return ParseRss(doc);
            case "RDF":
                return ParseRdf(doc);
            case "Atom":
                return ParseAtom(doc);
            default:
                throw new NotSupportedException(string.Format("{0} is not supported", feedType.ToString()));
        }
    }

    /// <summary>
    /// Parses an Atom feed and returns a <see cref="IList&amp;lt;Item&amp;gt;"/>.
    /// </summary>
    public virtual IList<Item> ParseAtom(XDocument doc)
    {
        try
        { 
            // Feed/Entry
            var entries = from item in doc.Root.Elements().Where(i => i.Name.LocalName == "entry")
                          select new Item
                          {
                              FeedType = "Atom",
                              Title = item.Elements().First(i => i.Name.LocalName == "title").Value,
                              Author = item.Elements().First(i => i.Name.LocalName == "author").Value,                     //must add child element "name"
                              Content = item.Elements().First(i => i.Name.LocalName == "summary").Value,
                              Tag = item.Elements().First(i => i.Name.LocalName == "field").Value,                       //must specify FIELD_TAG
                              Link = item.Elements().First(i => i.Name.LocalName == "link").Attribute("href").Value,
                              Updated = ParseDate(item.Elements().First(i => i.Name.LocalName == "updated").Value),

                          };
            return entries.ToList();
        }
        catch (Exception ex)
        {
            return new List<Item>();
        }
    }

    /// <summary>
    /// Parses an RSS feed and returns a <see cref="IList&amp;lt;Item&amp;gt;"/>.
    /// </summary>
    public virtual IList<Item> ParseRss(XDocument doc)
    {
        try
        { 
            // RSS/Channel/item
            var entries = from item in doc.Root.Descendants().First(i => i.Name.LocalName == "channel").Elements().Where(i => i.Name.LocalName == "item")
                          select new Item
                          {
                              FeedType = "RSS",
                              Content = item.Elements().First(i => i.Name.LocalName == "description").Value,
                              Author = item.Elements().First(i => i.Name.LocalName == "name").Value,                 //Newly added
                              Link = item.Elements().First(i => i.Name.LocalName == "link href").Value,
                              Updated = DateTime.Parse(item.Elements().First(i => i.Name.LocalName == "updated").Value),
                              Title = item.Elements().First(i => i.Name.LocalName == "title").Value
                          };
            return entries.ToList();
        }
        catch
        {
            return new List<Item>();
        }
    }

    /// <summary>
    /// Parses an RDF feed and returns a <see cref="IList&amp;lt;Item&amp;gt;"/>.
    /// </summary>
    public virtual IList<Item> ParseRdf(XDocument doc)
    {
        try
        { 
            // <item> is under the root
            var entries = from item in doc.Root.Descendants().Where(i => i.Name.LocalName == "item")
                          select new Item
                          {
                              FeedType = "RDF",
                              Content = item.Elements().First(i => i.Name.LocalName == "description").Value,
                              Author = item.Elements().First(i => i.Name.LocalName == "name").Value,                 
                              Link = item.Elements().First(i => i.Name.LocalName == "link href").Value,
                              Updated = DateTime.Parse(item.Elements().First(i => i.Name.LocalName == "updated").Value),
                              Title = item.Elements().First(i => i.Name.LocalName == "title").Value
                          };
            return entries.ToList();
        }
        catch
        {
            return new List<Item>();
        }
    }

    private DateTime ParseDate(string date)
    {
        DateTime result;
        if (DateTime.TryParse(date, out result))
            return result;
        else
            return DateTime.MinValue;
    }
}
 }

And here is the existing Service1.cs that I modified

public class Service1 : IService1
{
    public IList<Item> GetData()
    {


        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create("URL of the seedlist");

        request.Method = "GET";

        request.Accept = "application/atom+xml";

        request.ContentType = "application/atom+xml;type=entry";

        request.Credentials = new NetworkCredential("username", "password");

        ServicePointManager.ServerCertificateValidationCallback += new System.Net.Security.RemoteCertificateValidationCallback(ValidateServerCertificate);

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

        XDocument xDoc = XDocument.Load(new StreamReader(response.GetResponseStream()));



        FeedParser parser = new FeedParser();

        var items = parser.Parse(xDoc, "Atom");


        return items;

    }
    //for testing purpose only, accept any dodgy certificate... 
    public static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
    {
        return true;
    }

    public Item GetItemByLink(string url)
    {
        var items = GetData();
        foreach (var item in items)
        {
            if(item.Link == url)
            {
                return item;
            }

        }
        return null;

    }
}