Get String with Regex

Question

I am using to get String from Another String with this :

string t = "function " + funcName + "(.*?)};";

Regex regex = new Regex(t, RegexOptions.Singleline);
var v2 = regex2.Match(html);
string func = v2.Groups[1].Value;

I need to get this String :

a=a.split("");a=a.reverse();a=a.slice(1);a=a.reverse();return a.join("")

from :

function $n(a){a=a.split("");a=a.reverse();a=a.slice(1);a=a.reverse();return a.join("")};

That can be too:

someCodefunction Ab(a){a=a.split("");a=a.reverse();a=a.slice(1);a=a.reverse();return a.join("")};someCode

The funcName is : $n OR 'Ab'

I tried this code but sometimes it won't return the function content.Any idea what can be the problem?

Answer 1

YouTube has changed signature decode function. I am using below functions to decode youtube encoded signature. Regex seems so complicated to me, so i use "GetBetweenInString" function instead.

        /// <summary>
    /// 
    /// </summary>
    /// <param name="YouTubeVideoSignatureEncoded">encoded youtube signature</param>
    /// <param name="html5playerJScode">html5player-(.+?)\.js</param>
    /// <returns></returns>
    public string DecodeYouTubeSignature(string YouTubeVideoSignatureEncoded, string html5playerJScode)
    {

        //JScode=html5player javascript code
        string Function_Name = GetBetweenInString(html5playerJScode, ".signature=$", "(");
        //find the decoder function line
        string functionLine = GetBetweenInString(html5playerJScode, "function $" + Function_Name, "};");

        string[] Lines = functionLine.Split(';');
        for (int i = 0; i <= Lines.Length - 1; i++)
        {
            string Line = Lines[i].Trim();
            string jsVariable = GetBetweenInString(Line, "(", ")").Trim();
            if (Line.ToLower().Contains(".reverse"))
            {
                char[] charArray = YouTubeVideoSignatureEncoded.ToCharArray();
                Array.Reverse(charArray);
                YouTubeVideoSignatureEncoded = new string(charArray);
            }
            else if (Line.ToLower().Contains(".slice"))
            {
                YouTubeVideoSignatureEncoded = YouTubeVideoSignatureEncoded.Substring(Convert.ToInt32(jsVariable));
            }
        }
        return YouTubeVideoSignatureEncoded;// return decoded signature if possible.
    }

    /// <summary>
    /// string stackoverflow = GetBetweenInString("http://stackoverflow.com", "http://", ".com");
    /// </summary>
    /// <param name="str">http://stackoverflow.com</param>
    /// <param name="fromStr">http://</param>
    /// <param name="toStr">.com</param>
    /// <returns>stackoverflow</returns>
    public string GetBetweenInString(string str, string fromStr, string toStr)
    {
        try
        {
            if (string.IsNullOrEmpty(str) == true)
                return "";
            if (string.IsNullOrEmpty(fromStr) == true)
                return "";
            if (string.IsNullOrEmpty(toStr) == true)
                return "";
            string[] R = System.Text.RegularExpressions.Regex.Split(str, fromStr);
            if (R.Length == 1)
                return "";
            string[] R1 = System.Text.RegularExpressions.Regex.Split(R[1], toStr);
            if (R1.Length == 1)
            {
                return "";
            }
            else
            {
                return R1[0];
            }
        }
        catch
        {
            return "";
        }
    }