extracting hyperlinks using htmlagilitypack

Posted on 2012-12-28
Last Modified: 2012-12-29
how to get all the title hyperlinks on this web page ( present inside the paging table e.g. The first hyperlink for the title is ""

using htmlagilitypack
Question by:mmalik15
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LVL 75

Accepted Solution

käµfm³d   👽 earned 500 total points
ID: 38727851
I only mildly tested this, but it should work. At the least, it should get you started.

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;
using HtmlAgilityPack;

namespace ConsoleApplication41
    class Program
        /// <summary>
        /// Need this to share the extracted page number from the Javascript to the PreRequest handler below
        /// </summary>
        private static string pageNumber;

        static void Main(string[] args)
            string baseUrl = @"";
            HtmlWeb web = new HtmlWeb();
            HtmlDocument doc = web.Load(baseUrl);   // Load the base page
            HtmlNodeCollection pages = doc.DocumentNode.SelectNodes("//a[starts-with(@href, 'javascript:gotoPage')]");  // Find the Javascript function calls to change page
            List<int> visitedPages = new List<int>(pages.Count / 2);    // Since there are two places where a user can select pages, we make sure we don't get the same page twice by populating this
            Regex regPage = new Regex(@"\d+", RegexOptions.Compiled);   // For locating the page number in the javascript function call

            web.PreRequest = new HtmlWeb.PreRequestHandler(PreRequest); // Attach the handler for subsequent POST requests

            foreach (HtmlNode page in pages)
                HtmlAttribute href = page.Attributes["href"];
                string javascript = href.Value;
                Match matchPage = regPage.Match(javascript);

                if (matchPage.Success)  // Did we find a page number in the javascript function call?
                    HtmlNodeCollection titleAnchors;

                    pageNumber = matchPage.Value;
                    doc = web.Load(baseUrl, "POST");
                    titleAnchors = doc.DocumentNode.SelectNodes("//table//p[@class='list' and strong='Title: ']/a");

                    foreach (HtmlNode anchor in titleAnchors)
                        href = anchor.Attributes["href"];

        /// <summary>
        /// Need this in order to set the body of POST request
        /// </summary>
        static bool PreRequest(HttpWebRequest request)
            Stream strReqeust;
            byte[] data = Encoding.ASCII.GetBytes("start=" + pageNumber);

            request.ContentLength = data.Length;
            request.ContentType = "application/x-www-form-urlencoded";
            strReqeust = request.GetRequestStream();
            strReqeust.Write(data, 0, data.Length);

            return true;

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Also, I only quickly glanced over the Terms of Service for the site. I don't see anything prohibiting programmatic (i.e. non-browser) access to the site. Make sure you are not in violation of the site's TOS before you use the above.

Author Comment

ID: 38729009
many thanks for the comment kaufmed.

The only issue i m facing now is to get the total number of pages. I m trying to use this regex
(?s)(?i)Page 1.*([0-9]{3}).*

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 and its returning me 103 which is correct.

Can I ask how can we tweak this regex to pick 3 or more digit numbers as well?
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 38729284
Wht you have is close. I would ditch the dot-stars:


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Author Comment

ID: 38729396
thanks for the comment again but what I m asking is if in future we have values like below

Page 1 of 1037 or

Page 1 of 19

then what shall be our regex as this Page\s+1\s+of\s+([0-9]{3}) will always return three digits
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 38729451
Ah, sorry. Use:


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Author Closing Comment

ID: 38729704

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