C# 使用SyndicationFeed读取SyndicationItem中的非标准元素
在.NET3.5中,有一个SyndicationFeed将加载到RSS提要中,并允许您在其上运行LINQ 下面是我正在加载的RSS示例:C# 使用SyndicationFeed读取SyndicationItem中的非标准元素,c#,rss,syndication-feed,syndication-item,C#,Rss,Syndication Feed,Syndication Item,在.NET3.5中,有一个SyndicationFeed将加载到RSS提要中,并允许您在其上运行LINQ 下面是我正在加载的RSS示例: <rss version="2.0" xmlns:media="http://search.yahoo.com/mrss/"> <channel> <title>Title of RSS feed</title> <link>http://www.google.com</l
<rss version="2.0" xmlns:media="http://search.yahoo.com/mrss/">
<channel>
<title>Title of RSS feed</title>
<link>http://www.google.com</link>
<description>Details about the feed</description>
<pubDate>Mon, 24 Nov 08 21:44:21 -0500</pubDate>
<language>en</language>
<item>
<title>Article 1</title>
<description><![CDATA[How to use StackOverflow.com]]></description>
<link>http://youtube.com/?v=y6_-cLWwEU0</link>
<media:player url="http://youtube.com/?v=y6_-cLWwEU0" />
<media:thumbnail url="http://img.youtube.com/vi/y6_-cLWwEU0/default.jpg" width="120" height="90" />
<media:title>Jared on StackOverflow</media:title>
<media:category label="Tags">tag1, tag2</media:category>
<media:credit>Jared</media:credit>
<enclosure url="http://youtube.com/v/y6_-cLWwEU0.swf" length="233" type="application/x-shockwave-flash"/>
</item>
</channel>
RSS源标题
http://www.google.com
有关提要的详细信息
11月24日星期一08:21:44:21-0500
EN
第一条
http://youtube.com/?v=y6_-cLWwEU0
因堆栈溢出而受到冲击
tag1,tag2
贾里德
当我循环浏览这些项目时,我可以通过SyndicationItem的公共属性返回标题和链接
我似乎不知道如何获取机柜标记的属性或媒体标记的值。我试着用
SyndicationItem.ElementExtensions.ReadElementExtensions<string>("player", "http://search.yahoo.com/mrss/")
SyndicationItem.ElementExtensions.ReadElementExtensions(“播放器”http://search.yahoo.com/mrss/")
这两个方面有什么帮助吗?您缺少名称空间。使用和您的示例提要:
string xml = @"
<rss version='2.0' xmlns:media='http://search.yahoo.com/mrss/'>
<channel>
<title>Title of RSS feed</title>
<link>http://www.google.com</link>
<description>Details about the feed</description>
<pubDate>Mon, 24 Nov 08 21:44:21 -0500</pubDate>
<language>en</language>
<item>
<title>Article 1</title>
<description><![CDATA[How to use StackOverflow.com]]></description>
<link>http://youtube.com/?v=y6_-cLWwEU0</link>
<media:player url='http://youtube.com/?v=y6_-cLWwEU0' />
<media:thumbnail url='http://img.youtube.com/vi/y6_-cLWwEU0/default.jpg' width='120' height='90' />
<media:title>Jared on StackOverflow</media:title>
<media:category label='Tags'>tag1, tag2</media:category>
<media:credit>Jared</media:credit>
<enclosure url='http://youtube.com/v/y6_-cLWwEU0.swf' length='233' type='application/x-shockwave-flash'/>
</item>
</channel>
</rss>
";
XElement rss = XElement.Parse( xml );
XNamespace media = "http://search.yahoo.com/mrss/";
var player = rss.Element( "channel" ).Element( "item" ).Element(media + "player").Attribute( "url" );
player.Dump();
stringxml=@”
RSS源标题
http://www.google.com
有关提要的详细信息
11月24日星期一08:21:44:21-0500
EN
第一条
http://youtube.com/?v=y6_-cLWwEU0
因堆栈溢出而受到冲击
tag1,tag2
贾里德
";
XElement rss=XElement.Parse(xml);
XNamespace media=”http://search.yahoo.com/mrss/";
var player=rss.Element(“频道”).Element(“项目”).Element(媒体+“播放器”).Attribute(“url”);
player.Dump();
结果:url=”http://youtube.com/?v=y6_-cLWwEU0“
要查看的构造是:元素(media+“player”),它告诉Linq使用由“media”表示的名称空间以及元素名“player”
脑损伤一定是我造成的,我以为你在用Linq。无论如何,您需要考虑名称空间。您可以使用LINQ和XPathNavigator的组合来提取提要项的联合扩展(基于扩展的名称空间URI)。对于项目附件,您需要检查项目链接集合中具有RelationshipType附件的链接 例如:
HttpWebRequest webRequest = WebRequest.Create("http://www.pwop.com/feed.aspx?show=dotnetrocks&filetype=master") as HttpWebRequest;
using (Stream stream = webRequest.GetResponse().GetResponseStream())
{
XmlReaderSettings settings = new XmlReaderSettings();
settings.IgnoreComments = true;
settings.IgnoreWhitespace = true;
using(XmlReader reader = XmlReader.Create(stream, settings))
{
SyndicationFeed feed = SyndicationFeed.Load(reader);
foreach(SyndicationItem item in feed.Items)
{
// Get values of syndication extension elements for a given namespace
string extensionNamespaceUri = "http://www.itunes.com/dtds/podcast-1.0.dtd";
SyndicationElementExtension extension = item.ElementExtensions.Where<SyndicationElementExtension>(x => x.OuterNamespace == extensionNamespaceUri).FirstOrDefault();
XPathNavigator dataNavigator = new XPathDocument(extension.GetReader()).CreateNavigator();
XmlNamespaceManager resolver = new XmlNamespaceManager(dataNavigator.NameTable);
resolver.AddNamespace("itunes", extensionNamespaceUri);
XPathNavigator authorNavigator = dataNavigator.SelectSingleNode("itunes:author", resolver);
XPathNavigator subtitleNavigator = dataNavigator.SelectSingleNode("itunes:subtitle", resolver);
XPathNavigator summaryNavigator = dataNavigator.SelectSingleNode("itunes:summary", resolver);
XPathNavigator durationNavigator = dataNavigator.SelectSingleNode("itunes:duration", resolver);
string author = authorNavigator != null ? authorNavigator.Value : String.Empty;
string subtitle = subtitleNavigator != null ? subtitleNavigator.Value : String.Empty;
string summary = summaryNavigator != null ? summaryNavigator.Value : String.Empty;
string duration = durationNavigator != null ? durationNavigator.Value : String.Empty;
// Get attributes of <enclosure> element
foreach (SyndicationLink enclosure in item.Links.Where<SyndicationLink>(x => x.RelationshipType == "enclosure"))
{
Uri url = enclosure.Uri;
long length = enclosure.Length;
string mediaType = enclosure.MediaType;
}
}
}
}
HttpWebRequest-webRequest=webRequest.Create(“http://www.pwop.com/feed.aspx?show=dotnetrocks&filetype=master)作为HttpWebRequest;
使用(Stream-Stream=webRequest.GetResponse().GetResponseStream())
{
XmlReaderSettings设置=新建XmlReaderSettings();
settings.IgnoreComments=true;
settings.IgnoreWhitespace=true;
使用(XmlReader=XmlReader.Create(流、设置))
{
SyndicationFeed=SyndicationFeed.Load(读卡器);
foreach(feed.Items中的SyndicationItem项目)
{
//获取给定命名空间的联合扩展元素的值
字符串扩展名称空间URI=”http://www.itunes.com/dtds/podcast-1.0.dtd";
SyndicationElementExtension扩展名=item.ElementExtensions.Where(x=>x.OuterNamespace==扩展名NamespaceURI.FirstOrDefault();
XPathNavigator dataNavigator=新的XPathDocument(扩展名.GetReader()).CreateNavigator();
XmlNamespaceManager解析器=新的XmlNamespaceManager(dataNavigator.NameTable);
AddNamespace(“itunes”,extensionNamespaceUri);
XPathNavigator authorNavigator=dataNavigator.SelectSingleNode(“itunes:author”,解析器);
XPathNavigator subtitNavigator=dataNavigator.SelectSingleNode(“itunes:subtitle”,解析器);
XPathNavigator summaryNavigator=dataNavigator.SelectSingleNode(“itunes:summary”,解析器);
XPathNavigator durationNavigator=dataNavigator.SelectSingleNode(“itunes:duration”,解析器);
字符串author=authorNavigator!=null?authorNavigator.Value:string.Empty;
string subtitle=subtitleNavigator!=null?subtitleNavigator.Value:string.Empty;
string summary=summaryNavigator!=null?summaryNavigator.Value:string.Empty;
string duration=durationNavigator!=null?durationNavigator.Value:string.Empty;
//获取元素的属性
foreach(item.Links.Where(x=>x.RelationshipType==“附件”)中的SyndicationLink附件)
{
uriurl=enclosure.Uri;
长长度=外壳长度;
字符串mediaType=enclosure.mediaType;
}
}
}
}
以下是我如何使用SyndicationFeed从提要检索机柜链接的
static void Main(string[] args)
{
var feedUrl = "https://blog.stackoverflow.com/index.php?feed=podcast";
using (var feedReader = XmlReader.Create(feedUrl))
{
var feedContent = SyndicationFeed.Load(feedReader);
if (null == feedContent) return;
foreach (var item in feedContent.Items)
{
Debug.WriteLine("Item Title: " + item.Title.Text);
Debug.WriteLine("Item Links");
foreach (var link in item.Links)
{
Debug.WriteLine("Link Title: " + link.Title);
Debug.WriteLine("URI: " + link.Uri);
Debug.WriteLine("RelationshipType: " + link.RelationshipType);
Debug.WriteLine("MediaType: " + link.MediaType);
Debug.WriteLine("Length: " + link.Length);
}
}
}
}
结果如下:
项目名称:播客#50项目链接
链接标题:
URI:
关系类型:备用
媒体类型:
长度:0
链接标题:
URI:
关系类型:附件
媒体类型:音频/mpeg
长度:36580016
您可以从其关系类型中识别机柜链接。这将让您了解如何执行此操作:
using System.Linq;
using System.ServiceModel.Syndication;
using System.Xml;
using System.Xml.Linq;
SyndicationFeed=reader.Read();
foreach(feed.Items中的变量项)
{
foreach(item.ElementExtensions中的SyndicationElementExtension扩展)
{
XElement ele=extension.GetObject();
控制台写入线(元素值);
}
}
< /代码> 您是否正在检索扩展元素或XFLUE项的非XML内容,您可能需要考虑使用一个通用的帮助函数,例如:
private static T GetExtensionElementValue<T>(SyndicationItem item, string extensionElementName)
{
return item.ElementExtensions.First(ee => ee.OuterName == extensionElementName).GetObject<T>();
}
private static T GetExtensionElementValue(SyndicationItem项,字符串extensionElementName)
{
返回item.ElementExtensions.First(ee=>ee.OuterName==extensionElementName.GetObject();
}
根据元素是否保证存在,或者是否将其放入可重用库中,您可能需要
private static T GetExtensionElementValue<T>(SyndicationItem item, string extensionElementName)
{
return item.ElementExtensions.First(ee => ee.OuterName == extensionElementName).GetObject<T>();
}