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Aggregating Content: Consuming RSS Feeds in .NET

18 Feb 2017

The Role of RSS in Modern Data Aggregation

RSS (Really Simple Syndication) continues to be a standard format for distributing frequently updated web content. For developers, efficiently parsing these XML-based feeds is essential for building news aggregators, content dashboards, or automated notification systems.

Implementation Strategy: LINQ to XML

In the .NET ecosystem, XDocument (part of System.Xml.Linq) offers the most intuitive and readable approach for navigating XML structures.

Defining the Data Model

We begin by establishing a POCO structure to represent the core attributes of an RSS news item.

public class RssArticle
{
    public string Title { get; set; }
    public string Link { get; set; }
    public string Description { get; set; }
}

Orchestrating the XML Parsing Pipeline

The following implementation demonstrates how to load a remote feed—in this case, The New York Times—and project its XML segments into our strongly-typed model.

public List<RssArticle> FetchLatestArticles(string rssFeedUrl)
{
    // Initialize the list to hold aggregated items
    var articles = new List<RssArticle>();

    // Load the remote XML payload asynchronously
    XDocument feedData = XDocument.Load(rssFeedUrl);

    // Navigate to the "item" nodes within the RSS schema
    var rawItems = feedData.Descendants("item");

    foreach (var node in rawItems)
    {
        articles.Add(new RssArticle
        {
            Title = node.Element("title")?.Value,
            Link = node.Element("link")?.Value,
            Description = node.Element("description")?.Value
        });
    }

    return articles;
}

Key Takeaways

  1. Namespace Sensitivity: Some RSS feeds utilize specific XML namespaces (e.g., Media RSS or Content-encoded). When parsing these, ensure you use XNamespace to correctly target the elements.
  2. Robust Null Handling: External feeds are not always guaranteed to follow a strict schema. Utilizing the null-conditional operator (?.) prevents NullReferenceException when optional elements are missing.
  3. Performance: For high-frequency fetching, consider utilizing Stream objects for loading the document to optimize memory usage during parsing.

Source Code: A fully functional implementation is available for review on GitHub.