Show Atom feed as external content

Question

I hope that this is the correct place to ask this. I have a site that "spits out" an ATOM feed/seedlist that I want to show in SharePoint as an external content type. So far I know that this is done using the BCS and a WCF service. I'm a little bit stuck though as to how to create the WCF Service to allow the ATOM feed to show in SP, either online or SP2013.

So far I have found WCF Syndication, but I'm not entirely convinced that this is the correct way to go. Or is there maybe an easier way?

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;

}
}