How to get value of content from meta tag?

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hi,

I'm working on getting values from meta tags. So far I've gotten success but stuck at a point where i'm getting meta tag like below:

<meta content="/images/branding/googleg/1x/googleg_standard_color_128dp.png" itemprop="image">

through this i'm not able to extract url string which is in the content property of meta tag.

What I have tried:

Regex meta = new Regex(@"<meta\s*(?:(?:\b(\w|-)+\b\s*(?:=\s*(?:""[^""]*""|'" +
                          @"[^']*'|[^""'<> ]+)\s*)?)*)/?\s*>");

WebClient web = new WebClient();
					web.UseDefaultCredentials = true;
					string page = web.DownloadString(url);


                    WebClient client = new WebClient();

                    // Add a user agent header in case the 
                    // requested URI contains a query.

                    client.Headers.Add("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)");

                    Stream data = client.OpenRead(url);
                    StreamReader reader = new StreamReader(data);
                    string s = reader.ReadToEnd();
                    //Console.WriteLine(s);
                    data.Close();
                    reader.Close();



                    MatchCollection mc = meta.Matches(s);
                    int mIdx = 0;
                    foreach (Match m in mc)
                    {
                        for (int gIdx = 0; gIdx < m.Groups.Count; gIdx++)
                        {
                            
                            metadata.Add(m.Groups[gIdx].Value);
                        }
                        mIdx++;
                    }

Any Solution?

Posted 9-May-16 0:34am

Sachin Makwana

Updated 9-May-16 4:32am

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2 solutions

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Patrice T · Answer 1 · 2016-05-09T00:54:00

Use a RegEx debugger to see where the match fail
Debuggex: Online visual regex tester. JavaScript, Python, and PCRE.[^]
Paste your RegEx.
Paste your data to match.
Use the cursor to see where it fail.
When you have a valid RegEx, use Code Snipset button on top.

You will see the problem is not what you think.

perlre - perldoc.perl.org[^]

[Update]
Nota: There is more than 1 RegEx dialect, JavaScript regEx is not C# RegEx, difference is in details.
Find which dialect is used in C# and find differences.
By the way JavaScript and C# strings do not handle special chars the same way.

Sergey Alexandrovich Kryukov · Answer 2 · 2016-05-09T04:32:00

Solution 2

Instead of using Regex, you can use an HTML parser. I would recommend HTML Agility Pack, first of all: Html Agility Pack — Home[^].

—SA

Posted 9-May-16 4:32am

Sergey Alexandrovich Kryukov