Use LINQ and .NET 3.5 to Convert RSS to JSON
Scott Guthrie posted a great example of how to create a feed reader using LINQ to XML. Today, I see Tim Heuer's post on the JavaScriptSerializer type in .NET 3.5. So, I thought I would mash them up and show how to use LINQ to implement Tim's idea of converting RSS to JSON. Unfortunately, the JavaScriptSerializer is marked as obsolete with a note to use the DataContractJsonSerializer instead. Here is what a generic HTTP Handler would look like that mashes up these techniques using .NET 3.5.
<%@ WebHandler Language="C#" Class="Handler" %>
using System;
using System.Web;
using System.Linq;
using System.Xml.Linq;
using System.Web.Script.Serialization;
using System.Text;
using System.ServiceModel;
using System.Runtime.Serialization;
using System.Collections.Generic;
public class Handler : IHttpHandler {
public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "application/json";
XNamespace slashNamespace = "https://purl.org/rss/1.0/modules/slash/";
XDocument rssFeed = XDocument.Load("https://blogs.msdn.com/kaevans/rss.aspx");
var posts = from item in rssFeed.Descendants("item")
select new
{
Title = item.Element("title").Value,
Published = DateTime.Parse(item.Element("pubDate").Value),
Url = item.Element("link").Value,
NumComments = int.Parse(item.Element(slashNamespace + "comments").Value)
};
var newPosts = from item in posts
where (DateTime.Now - item.Published).Days < 7
select item;
List<FeedItem> itemsList = new List<FeedItem>();
foreach (var item in newPosts)
{
itemsList.Add(new FeedItem { Title = item.Title, Published = item.Published, Url = item.Url, NumComments = item.NumComments });
}
DataContractJsonSerializer ser = new DataContractJsonSerializer(itemsList.GetType());
ser.WriteObject(context.Response.OutputStream, itemsList);
}
public bool IsReusable {
get {
return false;
}
}
}
[DataContract]
public class FeedItem
{
[DataMember] public string Title { get; set; }
[DataMember] public DateTime Published { get; set; }
[DataMember] public string Url { get; set; }
[DataMember] public int NumComments { get; set; }
}
Look at how simple that is! Using LINQ, we are able to get just the posts that were published within the past 7 days, and we serialize the result to JSON. The results are shown below.
[{"NumComments":0,"Published":"\/Date(1188917760000-0500)\/",
"Title":"Using WCF, JSON, LINQ, and AJAX: Passing Complex Types to WCF Services with JSON Encoding",
"Url":"http:\/\/blogs.msdn.com\/kaevans\/archive\/2007\/09\/04\/using-wcf-json-linq-and-ajax-passing-complex-types-to-wcf-services-with-json-encoding.aspx"},
{"NumComments":4,"Published":"\/Date(1188836640000-0500)\/",
"Title":"WCF and LINQ",
"Url":"http:\/\/blogs.msdn.com\/kaevans\/archive\/2007\/09\/03\/wcf-and-linq.aspx"},
{"NumComments":1,"Published":"\/Date(1188652680000-0500)\/",
"Title":"Are you ready for some football?!?!",
"Url":"http:\/\/blogs.msdn.com\/kaevans\/archive\/2007\/09\/01\/are-you-ready-for-some-football.aspx"}]
So very cool. Look at how terse yet readable that code is! Contrast that to something like this from only a couple of years ago... Getting XML From Somewhere Else, which doesn't even cover filtering the XML and converting to JSON... which I probably would have transformed using some bizarre XSLT geekery. This is cleaner and easier to understand.
Comments
Anonymous
September 04, 2007
PingBack from http://msdnrss.thecoderblogs.com/2007/09/04/use-linq-and-net-35-to-convert-rss-to-json/Anonymous
September 04, 2007
Thanks for the code! That is some seriously clean code, and you're right, a couple of years ago, this would have been a mess. Can't wait to get the go ahead from my boss to start using this stuff!Anonymous
September 04, 2007
I couldn't let it go. Tim's post had me intrigued about how to convert RSS to JSON using some of theAnonymous
September 04, 2007
I couldn't let it go. Tim's post had me intrigued about how to convert RSS to JSON using someAnonymous
October 01, 2007
Earlier this year I blogged about a new language extensibility feature of C# and VB called "ExtensionAnonymous
October 01, 2007
Earlier this year I blogged about a new language extensibility feature of C# and VB called "ExtensionAnonymous
October 01, 2007
Earlier this year I blogged about a new language extensibility feature of C# and VB called "ExtensionAnonymous
October 02, 2007
It's been a while since I got time to read up on some blog posts and I stumbled on some interestingAnonymous
October 03, 2007
Earlier this year I blogged about a new language extensibility feature of C# and VB called "ExtensionAnonymous
October 07, 2007
Tip/Trick: Building a ToJSON() Extension Method using .NET 3.5Anonymous
October 09, 2007
【原文地址】 Tip/Trick: Building a ToJSON() Extension Method using .NET 3.5 【原文发表日期】 Monday, October 01, 2007Anonymous
October 20, 2007
Earlier this year I blogged about&;a new language extensibility&;feature of C# and VB calledAnonymous
April 10, 2008
Looks like this is an interesting topic to a lot of people since part 1 of this series made it to theAnonymous
December 16, 2008
It's been a while since I got time to read up on some blog posts and I stumbled on some interestingAnonymous
December 16, 2008
I was re-reading this post from Kirk Allen Evan's Blog when I decided to fool around with makingAnonymous
December 18, 2008
.NET3.5还包含一个新的newSystem.Runtime.Serialization.DataContractJsonSerializerclass类，你也可以用它来做JSON(J...Anonymous
January 05, 2009
It's been a while since I got time to read up on some blog posts and I stumbled on some interestingAnonymous
January 05, 2009
I was re-reading this post from Kirk Allen Evan's Blog when I decided to fool around with makingAnonymous
January 06, 2009
I was re-reading this post from Kirk Allen Evan's Blog when I decided to fool around with making