link example :

<img src="https://thumbs.com/thumbs/test.mp4/test1.mp4-3.jpg" alt="This is the description i want to get too" >

and the method i'm using to parse the links from html downloaded source file :

public List<string> GetLinks(string message)
        {
            List<string> list = new List<string>();
            string txt = message;
            foreach (Match item in Regex.Matches(txt, @"(http|ftp|https):\/\/([\w\-_] (?:(?:\.[\w\-_] ) ))([\w\-\.,@?^=%&amp;:/~\ #]*[\w\-\@?^=%&amp;/~\ #])?"))
            {
                if (item.Value.Contains("thumbs"))
                {
                    int index1 = item.Value.IndexOf("mp4");

                    string news = ReplaceLastOccurrence(item.Value, "thumbs", "videos");

                    if (index1 != -1)
                    {
                        string result = news.Substring(0, index1   3);
                        if (!list.Contains(result))
                        {
                            list.Add(result);
                        }
                    }
                }
            }

            return list;
        }

but this wil give only the link i want to get also the link description in this example:

This is a test

Then using it :

string[] files = Directory.GetFiles(@"D:\Videos\");
            foreach (string file in files)
            {
                foreach(string text in GetLinks(File.ReadAllText(file)))
                {
                    if (!videosLinks.Contains(text))
                    {
                        videosLinks.Add(text);
                    }
                }
               
            }

and when downloading the links :

private async void btnStartDownload_Click(object sender, EventArgs e)
        {
            if (videosLinks.Count > 0)
            {
                for (int i = 0; i < videosLinks.Count; i  )
                {
                    string fileName = System.IO.Path.GetFileName(videosLinks[i]);
                    await DownloadFile(videosLinks[i], @"D:\Videos\videos\"   fileName);
                }
            }
        }

but the fileName i want to be the description of each link.

CodePudding user response：

You can use Html Agility Pack which is an HTML parser written in C# to read/write DOM and supports plain XPATH or XSLT. In the example below you can retrieve the description in alt attribute and others.

Implementation:

using HtmlAgilityPack;
using System;
                    
public class Program
{
    public static void Main()
    {
        HtmlDocument doc = new HtmlDocument();
        var html = "<img src=\"https://thumbs.com/thumbs/test.mp4/test1.mp4-3.jpg\" alt=\"This is the description i want to get too\" >";
        doc.LoadHtml(html);
        HtmlNode image = doc.DocumentNode.SelectSingleNode("//img");

        Console.WriteLine("Source: {0}", image.Attributes["src"].Value);
        Console.WriteLine("Description: {0}", image.Attributes["alt"].Value);
        Console.Read();
    }
}

Demo:
https://dotnetfiddle.net/nAAZDL

Output:

Source: https://thumbs.com/thumbs/test.mp4/test1.mp4-3.jpg
Description: This is the description i want to get too

CodePudding user response：

If you use the code using regex, it will take more CPU cycle and perform slow. Use some library like AngleSharp.

I tried to write your code in AngleSharp. This is how I did it.

        string test = "<img src=\"https://thumbs.com/thumbs/test.mp4/test1.mp4-3.jpg\" alt=\"This is the description i want to get too\" >\r\n";
        var configuration = Configuration.Default.WithDefaultLoader();
        var context = BrowsingContext.New(configuration);
        using var doc = await context.OpenAsync(req => req.Content(test));

        string href = doc.QuerySelector("img").Attributes["alt"].Value;