Creating an Online RSS News Aggregator with ASP.NET Part 1

The Role of XML in Modern Web Integration

Every time a user opens a web page, a cascade of data moves behind the scenes - images, scripts, styles, and the page’s own markup. In a world where almost all devices are online, the ability to move data reliably between disparate systems has become more than a convenience; it is essential. XML, which stands for Extensible Markup Language, offers a simple, text‑based format that can be parsed by any programming language that provides an XML parser. Its design embraces readability and consistency, making it a natural bridge between systems that might otherwise speak different dialects.

XML’s structure consists of nested elements with clear start and end tags. Because the format is purely textual, it travels easily over HTTP, FTP, or any other transport protocol. The language enforces that every opening tag has a corresponding closing tag, that attribute values are quoted, and that special characters such as &, <, >, ", and ' are escaped. These rules keep XML documents well‑formed, allowing parsers to reconstruct the original data hierarchy without ambiguity. The fact that XML is case‑sensitive further reduces the risk of accidental mismatches.

These attributes make XML ideal for web syndication. News sites, blogs, and online journals publish their latest content in XML documents that external consumers can download, parse, and display. The most common syndication format is RSS 2.0, a specification that defines a predictable structure for a feed of items. An RSS file is itself an XML document that begins with an <rss> element, contains a <channel> child, and then one or more <item> elements describing individual entries.

A quick look at a real‑world example clarifies the concept. The MSDN Magazine publishes a syndication file at http://msdn.microsoft.com/msdnmag/rss/recent.xml that lists the newest articles. If you download that file, you’ll see a well‑structured XML document that follows the RSS 2.0 schema. Each article appears inside an <item> element, with child tags like <title>, <link>, <description>, and <pubDate>. Because the file is accessible over HTTP, any application - whether a desktop aggregator or a mobile app - can request it, parse the XML, and render the headlines to the user.

Before diving into the mechanics of generating an RSS feed from a database, it is helpful to be comfortable with a few foundational XML concepts. XPath is a language that allows you to address parts of an XML document, and XSLT lets you transform one XML structure into another. If those terms are new, the following resources provide a solid introduction:

What is XSLT and How Does it Relate to XML?
W3Schools XSL Tutorial
W3Schools XPath Tutorial
Having a grasp of these tools will pay dividends when you later need to extract data from the feed or transform it for display. The rest of this guide will show you how to turn a simple SQL Server table into a fully compliant RSS 2.0 feed using ASP.NET.
Generating RSS 2.0 Feeds from a SQL Server Database

Imagine you are a developer tasked with exposing the latest stories from a news website that stores its content in a Microsoft SQL Server 2000 database. The articles are kept in a table named Articles, and the fields that matter for syndication are ArticleID (an auto‑increment primary key), Title, Author, Description, and DatePublished. In a production scenario you might split authors into a separate table and normalize the schema, but for demonstration purposes the single table model will suffice.

The goal is to create an ASP.NET web page that queries the most recent records from Articles and outputs them as an RSS 2.0 XML document. To start, let’s review the essential parts of the RSS 2.0 specification. An RSS file begins with an <rss> element that declares the version, e.g., <rss version="2.0">. Inside that element sits a single <channel> element that provides information about the site producing the feed. The channel requires three child elements: title (the site name), link (the home page URL), and description (a brief summary of the site).

After the channel header, each news item appears in its own <item> element. While the spec allows many optional tags, the minimal set usually includes title, link, description, author, and pubDate. The pubDate field must follow the RFC 822 format, which looks like Mon, 07 Jul 2003 21:00:00 GMT. The rest of the elements are fairly straightforward: title is the headline, link is the URL to the full article, and description is a short synopsis. It is legal for an item to omit description as long as it contains a title, but including both creates a richer feed.

Below is a concise example of a complete RSS file that follows the 2.0 spec. Notice how every opening tag has a matching closing tag, how attribute values are quoted, and how special characters are escaped. The feed also demonstrates the optional nature of the description element by including it only in the second item.

Prompt
<rss version="2.0"> <channel> <title>Latest DataWebControls.com FAQs</title> <link>http://datawebcontrols.com</link> <description> This is the syndication feed for the FAQs at DataWebControls.com </description> <item> <title>Working with the DataGrid</title> <link>http://datawebcontrols.com/faqs/DataGrid.aspx</link> <pubDate>Mon, 07 Jul 2003 21:00:00 GMT</pubDate> </item> <item> <title>Working with the Repeater</title> <description> This article examines how to work with the Repeater control. </description> <link>http://datawebcontrols.com/faqs/Repeater.aspx</link> <pubDate>Tue, 08 Jul 2003 12:00:00 GMT</pubDate> </item> </channel> </rss>

When building the feed in ASP.NET, the simplest approach is to construct the XML string in code‑behind, using XmlWriter or string concatenation. A more robust method involves loading an XDocument, creating elements for each article, and then serializing the document to the response stream. Either technique ensures that the feed is valid and well‑formed.

Below is a sketch of how the code might look. The example uses SqlConnection to query the database, XmlWriter to build the feed, and Response.ContentType to set the correct MIME type. The GetRssFeed method pulls the five most recent articles and writes them directly to the HTTP response. Because the feed is sent as plain text, browsers and feed readers can pick it up automatically if the page’s URL is added to an aggregator.

Prompt
protected void Page_Load(object sender, EventArgs e) { Response.ContentType = "application/rss+xml"; Response.Cache.SetCacheability(HttpCacheability.NoCache); using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["NewsDB"].ConnectionString)) { conn.Open(); using (SqlCommand cmd = new SqlCommand("SELECT TOP 5 Title, Author, Description, DatePublished FROM Articles ORDER BY DatePublished DESC", conn)) using (SqlDataReader rdr = cmd.ExecuteReader()) { using (XmlWriter writer = XmlWriter.Create(Response.Output)) { writer.WriteStartDocument(); writer.WriteStartElement("rss"); writer.WriteAttributeString("version", "2.0"); writer.WriteStartElement("channel"); writer.WriteElementString("title", "Example News Feed"); writer.WriteElementString("link", "http://example.com"); writer.WriteElementString("description", "Latest stories from Example News"); while (rdr.Read()) { writer.WriteStartElement("item"); writer.WriteElementString("title", rdr["Title"].ToString()); writer.WriteElementString("link", $"http://example.com/articles/{rdr["ArticleID"]}"); writer.WriteElementString("author", rdr["Author"].ToString()); writer.WriteElementString("description", rdr["Description"].ToString()); writer.WriteElementString("pubDate", ((DateTime)rdr["DatePublished"]).ToString("r")); writer.WriteEndElement(); // item } writer.WriteEndElement(); // channel writer.WriteEndElement(); // rss writer.WriteEndDocument(); } } } }

After deploying the page, visiting http://example.com/RssFeed.aspx will render a valid RSS 2.0 feed. Feed readers such as Feedly or the built‑in reader in Outlook will automatically recognize the MIME type and display the latest headlines.

To test the feed’s validity, you can paste its URL into an online validator like

Tags

#rss #asp.net #xml #news-aggregator #web-development #csharp #feedreader