Right way to work with RSS in ASP.NET Core 1.0 RC2

问题:

What is the right/best way to get data from an RSS feed using ASP.Net Core 1.0 (RC2) in C#.

I want to work with the data in the RSS feed from my Wordpress blog which is https://blogs.msdn.microsoft.com/martinkearn/feed/

I know that in ASP.net 4.x, you'd use RssReader or SyndicationFeed but I cannot find an equivalent for ASP.net core.

This is as far as I have got which returns the raw feed but I do not know how to extract the data from it. I want to enumerate the items and get the title and description from each one

    var feedUrl = "https://blogs.msdn.microsoft.com/martinkearn/feed/";
    using (var client = new HttpClient())
    {
        client.BaseAddress = new Uri(feedUrl);
        var responseMessage = await client.GetAsync(feedUrl);
        var responseString = await responseMessage.Content.ReadAsStringAsync();
    }

回答1:

According to this issue, System.ServiceModel.Syndication has not yet been ported to ASP.NET Core. Currently, this leaves you with 2 options:

• Target the full .NET framework to provide access to SyndicationFeed
• Build your own XML parser using .NET Core to reproduce the functionality you require

Target the full .NET framework

This is undoubtedly the easiest approach depending on your requirements.

If you will be deploying to windows only then you can run ASP.NET Core on top of the .NET 4.X framework. To do this, update your project.json from something like this

frameworks": {
  "netcoreapp1.0": {
    "imports": [
      "dotnet5.6",
      "dnxcore50",
      "portable-net45+win8"
    ]
  }
}

to this:

frameworks": {
  "net452": {
     "frameworkAssemblies": {
         "System.ServiceModel": ""
     }
   }
}

Build your own XML Parser

This will give you the most flexibility, in that you will still be able to run cross platform using the .NET Core framework. It requires a little more work to deserialise the string you have already obtained, but there are lots of examples on how to do just this, e.g. http://www.anotherchris.net/csharp/simplified-csharp-atom-and-rss-feed-parser/

回答2:

For the sake of completeness, I'll include the final code which is a stripped down version of the sample @Sock linked to in the 'Build your own XML Parser' section of the answer. @Sock's answer is still the most complete answer, but this sample should be useful for anyone looking for a quick, simple code sample for ASP.NET Core.

Model

public class FeedItem
{
    public string Link { get; set; } 
    public string Title { get; set; } 
    public string Content { get; set; } 
    public DateTime PublishDate { get; set; } 
}

Controller

public class ArticlesController : Controller
{
    public async Task<IActionResult> Index()
    {
        var articles = new List<FeedItem>();
        var feedUrl = "https://blogs.msdn.microsoft.com/martinkearn/feed/";
        using (var client = new HttpClient())
        {
            client.BaseAddress = new Uri(feedUrl);
            var responseMessage = await client.GetAsync(feedUrl);
            var responseString = await responseMessage.Content.ReadAsStringAsync();

            //extract feed items
            XDocument doc = XDocument.Parse(responseString);
            var feedItems = from item in doc.Root.Descendants().First(i => i.Name.LocalName == "channel").Elements().Where(i => i.Name.LocalName == "item")
                            select new FeedItem
                            {
                                Content = item.Elements().First(i => i.Name.LocalName == "description").Value,
                                Link = item.Elements().First(i => i.Name.LocalName == "link").Value,
                                PublishDate = ParseDate(item.Elements().First(i => i.Name.LocalName == "pubDate").Value),
                                Title = item.Elements().First(i => i.Name.LocalName == "title").Value
                            };
            articles = feedItems.ToList();
        }

        return View(articles);
    }

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