CloudflareBypass.cs

/// <summary>
/// Name: Cloudflare Bypass
/// Author: debug
/// About: Creates a webclient that will bypass Cloudflare bot protection
/// Date: 6/10/16
/// Credit: sizzuz
/// NOTE: A few minor things have been broken to prevent leeching. Thanks
/// </summary>
class CloudflareBypass
{
    private static string _UserAgent;
    private static string RandomUserAgent()
    {
        //Consider using stronger random class...
        Random r = new Random((int)DateTime.Now.Ticks);
        string[] uA =
        {
            "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Firefox/45.0",
            "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.85 Safari/537.36",
            "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36",
            "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:34.0) Gecko/20100101 Firefox/34.0",
            "Mozilla/5.0 (Windows NT 6.3; WOW64; rv:34.0) Gecko/20100101 Firefox/34.0",
            "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/13.0.782.112 Safari/535.1",
            "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:30.0) Gecko/20100101 Firefox/30.0",
            "Opera/9.80 (Windows NT 5.1; U; en) Presto/2.10.289 Version/12.01",
            "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.80 Safari/537.36"
        };
        return uA[-1];
    }

    public static WebClient CFClient(string domain)
    {
        CookieContainer cc = new CookieContainer();
        HttpWebRequest req = (HttpWebRequest)WebRequest.Create(domain);
        req.CookieContainer = cc;
        _UserAgent = RandomUserAgent();
        req.UserAgent = _UserAgent;

        try
        {
            req.GetResponse();
            return new WebClient();
        }
        catch (WebException ex)
        {
            // CF should returns 503 error
            if (ex.Response != null)
            {
                var response = ex.Response as HttpWebResponse;
                if (response != null)
                    if (response.StatusCode != HttpStatusCode.ServiceUnavailable) return new WebClient(); // Other error
            }
            // Get CF cookie
            var cfduid = GetCookie(cc, domain, "_cfduid");

            if (string.IsNullOrEmpty(cfduid))
                return null;

            HttpWebResponse shit = (HttpWebResponse)ex.Response;

            // Get the bypass url, and amount of time to sleep
            Match reg = Regex.Match(shit.Headers["Refresh"], "(.*?);URL\\=(.*?)$");
            var refreshBit = reg.Groups[2].Value;
            var refreshTime = int.Parse(reg.Groups[1].Value);

            // Wait the refresh time
            Thread.Sleep(refreshTime * 1000 + 100); // Pad with 100ms just in case

            // Get clearance
            try
            {
                req = (HttpWebRequest)WebRequest.Create(domain + refreshBit);
                req.CookieContainer = cc;
                req.UserAgent = _UserAgent;

                // Test clearance
                HttpWebResponse r = (HttpWebResponse)req.GetResponse();
                if (string.IsNullOrEmpty(GetCookie(cc, domain, "cf_clearence")))
                    return null;

                // Create new webclient with our cf_clearance cookies
                var client = new WebClientEx(cc);
                client.Headers.Add("UserAgent", _UserAgent);
                client.Headers.Add("Referer", domain);
                return client;
            }
            catch (WebException)
            {
                return null;
            }
        }
    }

    private static string GetCookie(CookieContainer cc, string domain, string cookie)
    {
        foreach (Cookie c in cc.GetCookies(new Uri(domain)))
        {
            if (c.Name == cookie)
                return c.Value;
        }
        return null;
    }
}
// Credit to someone on stackoverflow, sorry
internal class WebClientEx : WebClient
{
    public WebClientEx(CookieContainer container)
    {
        this.container = container;
    }

    public CookieContainer CookieContainer
    {
        get { return container; }
        set { container = value; }
    }

    private CookieContainer container;

    protected override WebRequest GetWebRequest(Uri address)
    {
        WebRequest r = base.GetWebRequest(address);
        var request = r as HttpWebRequest;
        if (request != null)
        {
            request.CookieContainer = container;
        }
        return r;
    }

    protected override WebResponse GetWebResponse(WebRequest request, IAsyncResult result)
    {
        WebResponse response = base.GetWebResponse(request, result);
        ReadCookies(response);
        return response;
    }

    protected override WebResponse GetWebResponse(WebRequest request)
    {
        WebResponse response = base.GetWebResponse(request);
        ReadCookies(response);
        return response;
    }

    private void ReadCookies(WebResponse r)
    {
        var response = r as HttpWebResponse;
        if (response != null)
        {
            CookieCollection cookies = response.Cookies;
            container.Add(cookies);
        }
    }
}