how to extract a url's title, images and description using HTML Agility utility

问题

I want to extract Title, Description & images from URL using HTML Agility utility so far i am not able to find an example which is easy to understand & can help me to do it.

I would appreciate if some can help me with example so that i can extract title, description & give user choice to select image from series of image (some thing similar to Facebook when we share a link).

Updated:

I have place a label for title, desc and a button , textbox on the .aspx page & i fire following code on button click event. but it return null for all values. may be i am doing something wrong.

i used following sample URLhttp://edition.cnn.com/2012/10/31/world/asia/india/index.html?hpt=hp_t2

protected void btnGetURLDetails_Click(object sender, EventArgs e)
{
    HtmlDocument doc = new HtmlDocument();
    var response = txtURL.Text;
    doc.LoadHtml(response);

    String title = (from x in doc.DocumentNode.Descendants()
                    where x.Name.ToLower() == "title"
                    select x.InnerText).FirstOrDefault();

    String desc = (from x in doc.DocumentNode.Descendants()
                   where x.Name.ToLower() == "description"
                   select x.InnerText).FirstOrDefault();

    List<String> imgs = (from x in doc.DocumentNode.Descendants()
                         where x.Name.ToLower() == "img"
                         select x.Attributes["src"].Value).ToList<String>();

    lblTitle.Text = title;
    lblDescription.Text = desc;
}

Above code gets me null value for all variable

if i modify the code with this

HtmlDocument doc = new HtmlDocument();
        var url = txtURL.Text;

        var webGet = new HtmlWeb();
         doc = webGet.Load(url);

in this case it only get me value for title & description is null again

回答1:

protected void btnGetURLDetails_Click(object sender, EventArgs e)
{
    HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(new Uri(txtURL.Text));
    request.Method = WebRequestMethods.Http.Get;

    HttpWebResponse response = (HttpWebResponse)request.GetResponse();

    StreamReader reader = new StreamReader(response.GetResponseStream());

    String responseString = reader.ReadToEnd();

    response.Close();

    HtmlDocument doc = new HtmlDocument();
    doc.LoadHtml(responseString);

    String title = (from x in doc.DocumentNode.Descendants()
                where x.Name.ToLower() == "title"
                select x.InnerText).FirstOrDefault();

    String desc = (from x in doc.DocumentNode.Descendants()
               where x.Name.ToLower() == "meta"
               && x.Attributes["name"] != null
               && x.Attributes["name"].Value.ToLower() == "description"
               select x.Attributes["content"].Value).FirstOrDefault();

    List<String> imgs = (from x in doc.DocumentNode.Descendants()
                     where x.Name.ToLower() == "img"
                     select x.Attributes["src"].Value).ToList<String>();

   lblTitle.Text = title;
   lblDescription.Text = desc;

}

来源：https://stackoverflow.com/questions/13158091/how-to-extract-a-urls-title-images-and-description-using-html-agility-utility

标签

ASP.NET

webforms

html-agility-pack