CODEWITHSUNDEEP
c#htmlregexurl
CjC
CjC

Reputation: 59

Extracting url links within a downloaded txt file

Currently working on a url extractor for work. I'm trying to extract all http links/ href links from a downloaded html file and print the links on there own in a separate txt file.So far I've managed to get the entire html of a page downloaded its just extracting the links from it and printing them using Regex is a problem. Wondering if anyone could help me with this?

     private void button2_Click(object sender, EventArgs e)
    {
        Uri fileURI = new Uri(URLbox2.Text);

        WebRequest request = WebRequest.Create(fileURI);
        request.Credentials = CredentialCache.DefaultCredentials;
        WebResponse response = request.GetResponse();
        Console.WriteLine(((HttpWebResponse)response).StatusDescription);
        Stream dataStream = response.GetResponseStream();
        StreamReader reader = new StreamReader(dataStream);
        string responseFromServer = reader.ReadToEnd();

        SW = File.CreateText("C:\\Users\\Conal_Curran\\OneDrive\\C#\\MyProjects\\Web Crawler\\URLTester\\response1.htm");
        SW.WriteLine(responseFromServer);

        SW.Close();

        string text = System.IO.File.ReadAllText(@"C:\\Users\\Conal_Curran\\OneDrive\\C#\\MyProjects\\Web Crawler\\URLTester\\response1.htm");
        string[] links = System.IO.File.ReadAllLines(@"C:\\Users\\Conal_Curran\\OneDrive\\C#\\MyProjects\\Web Crawler\\URLTester\\response1.htm");



        Regex regx = new Regex(links, @"http://([\\w+?\\.\\w+])+([a-zA-Z0-9\\~\\!\\@\\#\\$\\%\\^\\&\\*\\(\\)_\\-\\=\\+\\\\\\/\\?\\.\\:\\;\\'\\,]*)?", RegexOptions.IgnoreCase);

        MatchCollection mactches = regx.Matches(text);

        foreach (Match match in mactches)
        {
            text = text.Replace(match.Value, "<a href='" + match.Value + "'>" + match.Value + "</a>");
        }

        SW = File.CreateText("C:\\Users\\Conal_Curran\\OneDrive\\C#\\MyProjects\\Web Crawler\\URLTester\\Links.htm");
        SW.WriteLine(links);
    }

Upvotes: 1

Views: 1123

Answers (1)

Veverke
Veverke

Reputation: 11358

In case you do not know, this can be achieved (pretty easily) using one of the html parser nuget packages available.

I personally use HtmlAgilityPack (along with ScrapySharp, another package) and AngleSharp.

With only the 3 lines above, you have all the hrefs in the document loaded by your http get request, using HtmlAgilityPack:

/*
  do not forget to include the usings:
  using HtmlAgilityPack;
  using ScrapySharp.Extensions;
*/

HtmlWeb w = new HtmlWeb();
//since you have your html locally stored, you do the following:

//P.S: By prefixing file path strings with @, you are rid of having to escape slashes and other fluffs.
var doc = HtmlDocument.LoadHtml(@"C:\Users\Conal_Curran\OneDrive\C#\MyProjects\Web Crawler\URLTester\response1.htm");

//for an http get request
//var doc = w.Load("yourAddressHere");
var hrefs = doc.DocumentNode.CssSelect("a").Select(a => a.GetAttributeValue("href"));

Upvotes: 2

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