Web scraper using HtmlAgilityPack

.net c# html-agility-pack visual-studio-2012 web-scraping

Question

I am new to C# so this might be very obvious how to get this to work or way too complex for me but I am trying to setup and scrape a web page using the HtmlAgilityPack. Currently my code compiles but when I write the string I only get 1 result and it happens to be the last result from the li in the ul. The reason for the string split is so I can eventually output the title and description strings into a .csv for further use. I am just unsure what to do next thus, why I am asking for any help/understanding/ideas/thoughts/suggestions that can be offered. Thank you!

    private void button1_Click(object sender, EventArgs e)
    {
        List<string> cities = new List<string>();
        //var xpath = "//h2[span/@id='Cities']";
        var xpath = "//h2[span/@id='Cities']" + "/following-sibling::ul[1]" + "/li";

        WebClient web = new WebClient();
        String html = web.DownloadString("http://wikitravel.org/en/Vietnam");

        hap.HtmlDocument doc = new hap.HtmlDocument();
        doc.LoadHtml(html);


        foreach (hap.HtmlNode node in doc.DocumentNode.SelectNodes(xpath)) 
        {
            string all = node.InnerText;

            //splits text between '—', '-' or ' ' into 2 parts
            string[] split = all.Split(new char[] { '—', ' ', '-' }, StringSplitOptions.None);

            string title;
            string description;

            int nodeCount;
            nodeCount = node.ChildNodes.Count;

            if (nodeCount == 2)
            {
                title = node.ChildNodes[0].InnerText;
                description = node.ChildNodes[1].InnerText;
            }
            else if (nodeCount == 4)
            {
                title = node.ChildNodes[0].InnerText;
                description = node.ChildNodes[1].InnerText + node.ChildNodes[2].InnerText;
            }
            else
            {
                title = "Error";
                description = "The node cound was not 2 or 3.  Check the div section.";
            }

            System.IO.StreamWriter write = new System.IO.StreamWriter(@"C:\Users\cbrannin\Desktop\textTest\testText.txt");
            write.WriteLine(all);

            write.Close();


        }

    }
}

Accepted Answer

One problem is that you're overwriting the output file each time through the loop. You probably want to do this:

using (StreamWriter write = new StreamWriter(@"filename"))
{
    foreach (hap.HtmlNode node in doc.DocumentNode.SelectNodes(xpath))
    {
        // do your thing
        write.WriteLine(all);
    }
}

Also, have you single-stepped this to see if you're getting more than one HtmlNode from your SelectNode call?

Finally, I don't see where you're doing anything with the title or description. Were you planning to use those for something else?



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Licensed under: CC-BY-SA with attribution
Not affiliated with Stack Overflow
Is this KB legal? Yes, learn why