我想知道 HtmlAgilityPack 读取包含 xsl 文件以呈现 html 的 xml 文件的最佳方法。 HtmlDocument 类上是否有任何设置可以帮助实现这一点,或者我是否必须找到一种方法来执行转换,然后再使用 HtmlAgiliyPack 加载它?如果后者是肯定的,有人知道进行这种转换的好的库或方法吗?下面是一个返回带有 xls 文件和我想使用的代码的 xml 的网站示例。
var uri = new Uri("http://www.skechers.com/");
var request = (HttpWebRequest)WebRequest.Create(url);
var cookieContainer = new CookieContainer();
request.CookieContainer = cookieContainer;
request.UserAgent = @"Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5";
request.Method = "GET";
request.AllowAutoRedirect = true;
request.Timeout = 15000;
var response = (HttpWebResponse)request.GetResponse();
var page = new HtmlDocument();
page.OptionReadEncoding = false;
var stream = response.GetResponseStream();
page.Load(stream);
此代码不会抛出任何错误,但解析的是 xml 而不是转换,这正是我想要的。
最佳答案
Html Agility Pack 可以在两点上帮助您:
1) 比较容易得到Xml处理指令,因为它把PI数据解析成Html,所以会转成属性
2) HtmlDocument 实现了 IXPathNavigable,因此它可以直接由 .NET Xslt 转换引擎进行转换。
这是一段有效的代码。我必须添加一个特定的 XmlResover 来正确处理 Xslt 转换,但我认为这是这个 skechers 案例所特有的。
public static void DownloadAndProcessXml(string url, string userAgent, string outputFilePath)
{
using (XmlTextWriter writer = new XmlTextWriter(outputFilePath, Encoding.UTF8))
{
DownloadAndProcessXml(url, userAgent, writer);
}
}
public static void DownloadAndProcessXml(string url, string userAgent, XmlWriter output)
{
UserAgentXmlUrlResolver resolver = new UserAgentXmlUrlResolver(url, userAgent);
// WebClient is an easy to use class.
using (WebClient client = new WebClient())
{
// download Xml doc. set User-Agent header or the site won't answer us...
client.Headers[HttpRequestHeader.UserAgent] = resolver.UserAgent;
HtmlDocument xmlDoc = new HtmlDocument();
xmlDoc.Load(client.OpenRead(url));
// determine xslt (note the xpath trick as Html Agility Pack does not support xml processing instructions)
string xsltUrl = xmlDoc.DocumentNode.SelectSingleNode("//*[name()='?xml-stylesheet']").GetAttributeValue("href", null);
// download Xslt doc
client.Headers[HttpRequestHeader.UserAgent] = resolver.UserAgent;
XslCompiledTransform xslt = new XslCompiledTransform();
xslt.Load(new XmlTextReader(client.OpenRead(url + xsltUrl)), new XsltSettings(true, false), null);
// transform Html/Xml doc into new Xml doc, easy as HtmlDocument implements IXPathNavigable
// note the use of a custom resolver to overcome this Xslt resolve requests
xslt.Transform(xmlDoc, null, output, resolver);
}
}
// This class is needed during transformation otherwise there are errors.
// This is probably due to this very specific Xslt file that needs to go back to the root document itself.
public class UserAgentXmlUrlResolver : XmlUrlResolver
{
public UserAgentXmlUrlResolver(string rootUrl, string userAgent)
{
RootUrl = rootUrl;
UserAgent = userAgent;
}
public string RootUrl { get; set; }
public string UserAgent { get; set; }
public override object GetEntity(Uri absoluteUri, string role, Type ofObjectToReturn)
{
WebClient client = new WebClient();
if (!string.IsNullOrEmpty(UserAgent))
{
client.Headers[HttpRequestHeader.UserAgent] = UserAgent;
}
return client.OpenRead(absoluteUri);
}
public override Uri ResolveUri(Uri baseUri, string relativeUri)
{
if ((relativeUri == "/") && (!string.IsNullOrEmpty(RootUrl)))
return new Uri(RootUrl);
return base.ResolveUri(baseUri, relativeUri);
}
}
你这样调用它:
string url = "http://www.skechers.com/";
string ua = @"Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5";
DownloadAndProcessXml(url, ua, "skechers.html");
关于c# - HtmlAgilityPack 可以处理一个 xsl 文件自带的 xml 文件来渲染 html 吗?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/5385010/