Parsing RSS 1.0 with C#/MVC 2 - asp.net-mvc-2

Question

First, I cant believe that anyone in 2011 is still using RSS 1.0, guess you really learn something new. Well I'm trying to parse their feed and put the content on my clients site (I got permissions so no law breaking here). As you can imagine my first attempt failed miserably (was wrting code for 2.0) so I went back to the drawing board and here's what I've come up with.
RssController
public virtual ActionResult Index()
{
List<RssFeedItem> rssList = new List<RssFeedItem>();
XmlDocument doc = new XmlDocument();
XmlNamespaceManager manager = new XmlNamespaceManager(doc.NameTable);
manager.AddNamespace("rdf", "http://www.w3.org/1999/02/22-rdf-syntax-ns#");
manager.AddNamespace("rss", "http://purl.org/rss/1.0/");
XmlTextReader reader = new XmlTextReader("http://wdfw.wa.gov/news/newsrss.php");
doc.Load(reader);
XmlNodeList nodes = doc.SelectNodes("/rdf:RDF//rss:item",manager);
foreach(XmlNode node in nodes)
{
XmlNodeList aboutNode = node.SelectNodes("rss:about", manager);
XmlNodeList titleNode = node.SelectNodes("rss:title", manager);
XmlNodeList linkNode = node.SelectNodes("rss:link", manager);
var item = new RssFeedItem
{
Link = linkNode.Count == 0 ? "" : linkNode[0].InnerText,
Title = titleNode.Count == 0 ? "" : titleNode[0].InnerText,
About = aboutNode.Count == 0 ? "" : aboutNode[0].InnerText
};
rssList.Add(item);
}
return View(rssList);
}
I'm attempting to do this utilizing a partial view (ascs) and that looks like this
Index.aspx
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<GodsCreationTaxidermy.Models.RssFeedItem>" %>
<%
foreach (RssFeedItem item in (IEnumerable<RssFeedItem>)ViewData.Model)
{
Response.Write(string.Format("<div id={0}><a href={1} target=\"_blank\" /> <strong>{2}</strong></div>",
Model.About.Truncate(5), Model.Link, Model.Title.Truncate(25)));
} %>
Then I try RenderPartial in mySite.Master
<% Html.RenderPartial("Index");%>
The problem is that the site never even loads, or even gives some kind of error, it just sits tere with FF's litte loading icon spinning.
EDIT
Well I've made some major changes to my code from earlier, and same result, no error and it doesnt load the site even (just sits & spins). Here's the code from the Controller
[MoveFormsScript]
[CanonicalUrlAttribute("Rss")]
public virtual ActionResult Index()
{
return View(new RssList());
}
Now the code from RssList
[UIHint("Feeds")]
public SelectList Feeds { get; private set; }
[Required(ErrorMessage = "Rss Feeduired")]
public string Feed { get; set; }
public RssList()
{
this.Feeds = GetRssFeed(null);
}
public SelectList GetRssFeed(string selectedValue)
{
List<RssFeedItem> rssList = new List<RssFeedItem>();
XmlDocument doc = new XmlDocument();
XmlNamespaceManager manager = new XmlNamespaceManager(doc.NameTable);
manager.AddNamespace("rdf", "http://www.w3.org/1 999/02/22-rdf-syntax-ns#");
manager.AddNamespace("rss", "http://purl.org/rss/1.0/");
XmlTextReader reader = new XmlTextReader("http://wdfw.wa.gov/news/newsrss.php");
doc.Load(reader);
XmlNodeList nodes = doc.SelectNodes("/rdf:RDF//rss:item", manager);
foreach (XmlNode node in nodes)
{
XmlNodeList aboutNode = node.SelectNodes("rss:about", manager);
XmlNodeList titleNode = node.SelectNodes("rss:title", manager);
XmlNodeList linkNode = node.SelectNodes("rss:link", manager);
var item = new RssFeedItem
{
Link = linkNode.Count == 0 ? "" : linkNode[0].InnerText,
Title = titleNode.Count == 0 ? "" : titleNode[0].InnerText,
About = aboutNode.Count == 0 ? "" : aboutNode[0].InnerText
};
rssList.Add(item);
}
return new SelectList(rssList, "Link", "Title", selectedValue);
}
And finally my partial view
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<GodsCreationTaxidermy.Helpers.BusinessDTO.RssList>" %>
<%
foreach (var item in (IEnumerable<RssList>)ViewData.Model)
{
Response.Write(string.Format("<div id=\"{0}\"><a href=\"{1}\" target=\"_blank\" /> <strong>{2}</strong></div>",
item.Feed[0].ToString().Truncate(10), item.Feed[1], item.Feed[2].ToString().Truncate(100)));
} %>
Can anyone help me?

Answer 1

Change the instantiation of the XmlNodeList is the RssList class to:
XmlNodeList nodes = doc.SelectNodes("//rss:item[./rss:link]", manager);
Then change your ViewUserControl to this:
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl" %><ul>
<%
RssList viewModel = ViewData.Model as RssList;
if (viewModel.Feeds.Count() > 0)
{
foreach (SelectListItem item in viewModel.Feeds)
{ %>
<li>
<%
Response.Write(String.Format("<a href='{0}' target='_blank'>{1}</a>", item.Value, item.Text));
}%>
</li>
<%
}
%></ul>
Seems to work for me.

Answer 2

There are a few problems I see here. Your control is expecting a single RssList, the Controller is returning a select list, and your foreach is enumerating over what it thinks is an IEnumerable<RssList>. Also, you're doing manual response.writes in the partial view. The markup would be cleaner if you didn't do that.
Let's start with the RssList class first. It looks like your first approach was actually what you wanted, the problem was just what you were doing in the partial view.
public class RssList
{
[UIHint("Feeds")]
public IEnumerable<RssFeedItem> Feeds { get; private set; }
[Required(ErrorMessage = "Rss Feed Required")]
public string Feed { get; set; }
public RssList()
{
this.Feeds = GetRssFeed(null);
}
public IEnumerable<RssFeedItem> GetRssFeed(string selectedValue)
{
List<RssFeedItem> rssList = new List<RssFeedItem>();
XmlDocument doc = new XmlDocument();
XmlNamespaceManager manager = new XmlNamespaceManager(doc.NameTable);
manager.AddNamespace("rdf", "http://www.w3.org/1 999/02/22-rdf-syntax-ns#");
manager.AddNamespace("rss", "http://purl.org/rss/1.0/");
XmlTextReader reader = new XmlTextReader("http://wdfw.wa.gov/news/newsrss.php");
doc.Load(reader);
XmlNodeList nodes = doc.SelectNodes(
"/rdf:RDF//rss:item[./rss:link./rss:title./rss:about]", manager);
foreach (XmlNode node in nodes)
{
XmlNodeList aboutNode = node.SelectNodes("rss:about", manager);
XmlNodeList titleNode = node.SelectNodes("rss:title", manager);
XmlNodeList linkNode = node.SelectNodes("rss:link", manager);
var rssItem = new RssFeedItem
{
Link = linkNode.Count == 0 ? "" : linkNode[0].InnerText,
Title = titleNode.Count == 0 ? "" : titleNode[0].InnerText,
About = aboutNode.Count == 0 ? "" : aboutNode[0].InnerText
};
rssList.Add(rssItem);
}
return rssList;
}
}
Now instead of a SelectList, we're returning an IEnumerable<RssFeedItem>. It's preferable not to manipulate the UI from the code if possible. So let's see if we need to work any magic on the controller. The only thing I see there is that you can exclude "Index" from the View function (it's implied because that is the name of the controller operation.
return PartialView(viewModel);
Now on to the view...let's see if we can make that look better
<%# Control Language="C#"
Inherits="System.Web.Mvc.ViewUserControl<GodsCreationTaxidermy.Helpers.BusinessDTO.RssList>" %>
<%
foreach (var rssItem in ViewData.Model.Feeds)
{
%>
<div id="<%=rssItem.Title%>">
<a href="<%=rssItem.Link%>" target="_blank">
<strong><%=rssItem.Title%></strong>
</a>
<%
}
%>
There I think that should do it for you...let me know if you run into any problems.

Answer 3

I'm not really familiar with the System.Web.Mvc.SelectList class much less the namespace, but I noticed your using a string for the selectedValue parameter. Should it be an RssFeedItem object instead?
[edit]
Ran your xml code section through some powershell hurdles and here's what I get.
$doc = New-Object Xml.XmlDocument;
$manager = New-Object Xml.XmlNamespaceManager $doc.NameTable;
$manager.AddNamespace("rdf", "http://www.w3.org/1 999/02/22-rdf-syntax-ns#");
$manager.AddNamespace("rss", "http://purl.org/rss/1.0/");
$reader = New-Object Xml.XmlTextReader("http://wdfw.wa.gov/news/newsrss.php");
$doc.Load($reader);
#doesn't work
"Doesn't work"
$doc.SelectNodes("//rss:item[./rss:link./rss:title./rss:about]", $manager) | measure | select count
#this is an invalid xpath query, there are no operators between the nodes specified in the [].
#Also, in the xml document we're looking at, there is no node named "about". "about" is an attibute to the "item" node.
#works
"Works"
$doc.SelectNodes("//rss:item[./rss:link and ./rss:title]", $manager) | measure | select count
#Even though we only have the "link" and "title" nodes in the [], everything is returned.
#That's because we're telling SelectNodes to return the "item" nodes themselves.

Answer 4

Can a mod merge this feed with this one MVC2 - Consume RSS feed with RDF and namespace http://www.w3.org/1999/02/22-rdf-syntax-ns#'. I forgot I had already asked

Answer 5

Made some more changes dor those who are trying to help me. Here's the controllers code
[MoveFormsScript]
[CanonicalUrlAttribute("Rss")]
public virtual ActionResult Index()
{
var viewModel = new RssList();
return PartialView("Index", viewModel);
}
Then I created a class (RssList), which is where the bulk of the work is done
RssList
[UIHint("Feeds")]
public SelectList Feeds { get; private set; }
[Required(ErrorMessage = "Rss Feed Required")]
public string Feed { get; set; }
public RssList()
{
this.Feeds = GetRssFeed(null);
}
public SelectList GetRssFeed(string selectedValue)
{
List<RssFeedItem> rssList = new List<RssFeedItem>();
XmlDocument doc = new XmlDocument();
XmlNamespaceManager manager = new XmlNamespaceManager(doc.NameTable);
manager.AddNamespace("rdf", "http://www.w3.org/1 999/02/22-rdf-syntax-ns#");
manager.AddNamespace("rss", "http://purl.org/rss/1.0/");
XmlTextReader reader = new XmlTextReader("http://wdfw.wa.gov/news/newsrss.php");
doc.Load(reader);
XmlNodeList nodes = doc.SelectNodes("/rdf:RDF//rss:item[./rss:link./rss:title./rss:about]", manager);
foreach (XmlNode node in nodes)
{
XmlNodeList aboutNode = node.SelectNodes("rss:about", manager);
XmlNodeList titleNode = node.SelectNodes("rss:title", manager);
XmlNodeList linkNode = node.SelectNodes("rss:link", manager);
var rssItem = new RssFeedItem
{
Link = linkNode.Count == 0 ? "" : linkNode[0].InnerText,
Title = titleNode.Count == 0 ? "" : titleNode[0].InnerText,
About = aboutNode.Count == 0 ? "" : aboutNode[0].InnerText
};
rssList.Add(rssItem);
}
return new SelectList(rssList, "Link", "Title", selectedValue);
}
This is the Index.ascx
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<GodsCreationTaxidermy.Helpers.BusinessDTO.RssList>" %>
<%
foreach (RssList rssItem in ViewData.Model)
{
Response.Write(string.Format("<div id=\"{0}\"><a href=\"{1}\" target=\"_blank\" /> <strong>{2}</strong></div>",
rssItem.Feed[0].ToString().Truncate(10), rssItem.Feed[1], rssItem.Feed[2].ToString().Truncate(100)));
} %>
And a normal call
<% Html.RenderPartial("Index");%>
}
FeedItemCass
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace GodsCreationTaxidermy.Models
{
public class RssFeedItem
{
public string Link { get; set; }
public string Title { get; set; }
public string About { get; set; }
}
}