2captcha service integration for solving recaptcha by C# code

The code in C# for integrating 2captcha service.

See the Python code here with more explanation on 2captcha service using.

using System.IO;
using System;
using System.Net; 
using System.Text; 

class Recaptcha2captcha
{     
    private static string captcha_service_key;
    private string site_key;
    private string page_url; 
     
    public void setServiceKey(string service_key)
    {        
        Recaptcha2captcha.captcha_service_key = service_key;
    }
    public void setSiteKey(string site_key)
    {
        this.site_key = site_key; 
    }
    public void setPageUrl(string page_url)
    {
        this.page_url = page_url; 
    }
  
    public string SendRequest() // HTTP POST
    { 
        try
        {
            System.Net.ServicePointManager.Expect100Continue = false;
            var request = (HttpWebRequest)WebRequest.Create("http://2captcha.com/in.php");
           
            var postData = "key="+ Recaptcha2captcha.captcha_service_key +"&method=userrecaptcha&googlekey=" + this.site_key + "&page_url=" + this.page_url;
            var data = Encoding.ASCII.GetBytes(postData);

            request.Method = "POST";

            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = data.Length;

            using (var stream = request.GetRequestStream())
            {
                stream.Write(data, 0, data.Length);
            }

            var response = (HttpWebResponse)request.GetResponse();

            var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
 
            response.Close();
 
            if (responseString.Contains("OK|"))
            {
                return responseString;
            }
            else
            {
                return "2captcha service return error. Error code:" + responseString;
            }
        }
        catch (Exception e)
        { 
            return e.Message;
        }

    }
    public string SubmitForm(string RecaptchaResponseToken)  // HTTP POST
    { 
        // var page_url = "http://testing-ground.scraping.pro/recaptcha"; 
        try
        {
            System.Net.ServicePointManager.Expect100Continue = false;
            var request = (HttpWebRequest)WebRequest.Create(this.page_url);
           
            var postData = "submit=submin&g-recaptcha-response="  + RecaptchaResponseToken;
            var data = Encoding.ASCII.GetBytes(postData);

            request.Method = "POST";

            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = data.Length;

            using (var stream = request.GetRequestStream())
            {
                stream.Write(data, 0, data.Length);
            }

            var response = (HttpWebResponse)request.GetResponse();

            var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
 
            response.Close();
 
            return responseString;
        }
        catch (Exception e)
        { 
            return e.Message;
        }

    }
    
    // the request to retrieve g-recaptcha-response token from 2captcha service
    public string getToken(string captcha_id)  // HTTP GET
    {
        WebClient webClient = new WebClient();
        webClient.QueryString.Add("key", Recaptcha2captcha.captcha_service_key);
        webClient.QueryString.Add("action", "get");
        webClient.QueryString.Add("id", captcha_id);
        
        return webClient.DownloadString("http://2captcha.com/res.php");
    }
    // validate site with returned token thru proxy.php  
    public string getValidate(string token)
    {
        WebClient webClient = new WebClient();
        webClient.QueryString.Add("response", token); 
        return webClient.DownloadString("http://testing-ground.scraping.pro/proxy.php");
    }
}

class Program
{
    static void Main(string[] args)
    {  
        if (args.Length != 1)
        {
            System.Console.WriteLine("Usage: main.exe <2captcha_service_key>");
            return;
        }
        string service_key = args[0];
        // Console.WriteLine("2captcha service key: " + service_key); 
        
        Recaptcha2captcha service = new Recaptcha2captcha();
        
        // we set 2captcha service key and target google site_key
        service.setServiceKey(service_key);
        service.setSiteKey("6Lf5CQkTAAAAAKA-kgNm9mV6sgqpGmRmRMFJYMz8");
        serivce.service.setPageUrl("http://testing-ground.scraping.pro/recaptcha"); 
        
        var resp = service.SendRequest();
        var gcaptchaToken = "";
        Console.WriteLine(resp.Substring( 3, resp.Length-3));
        if (resp.Contains("OK|")){
            // loop till the service solves captcha and gets g-recaptcha-response token
            var i=0;
            while (i++ <= 20) 
            {
                System.Threading.Thread.Sleep(5000); // sleep 5 seconds
                Console.WriteLine("Captcha is being solved for {0} seconds", i*5);
                gcaptchaToken = service.getToken(resp.Substring( 3, resp.Length-3)); 
                if (gcaptchaToken.Contains("OK|"))
                { 
                    break;
                }
            }
            
            
            if (gcaptchaToken.Contains("OK|"))
            { 
                var RecaptchaResponseToken = gcaptchaToken.Substring(3, gcaptchaToken.Length-3);
                Console.WriteLine("g-recaptcha-response token:  " + RecaptchaResponseToken );
                
                // make google to validate g-recaptcha-response token 
                var iSvalid = service.getValidate(RecaptchaResponseToken); 
                Console.WriteLine("Token is validated by google: " + iSvalid );
                
                // submit form to the target site
                var SubmitFormResp = service.SubmitForm(RecaptchaResponseToken);
                Console.WriteLine("Submit form return: " + SubmitFormResp );
                
            } else {
                Console.WriteLine("Captcha has not been solved. Error code: " + gcaptchaToken);
                //Environment.Exit(0);
            }
            
        } else {
            Console.WriteLine("Error: " + resp);
            //Environment.Exit(0);
        }
        Console.Read();
    }
}

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using System.IO;

using System;

using System.Net;

using System.Text;

class Recaptcha2captcha

{

private static string captcha_service_key;

private string site_key;

private string page_url;

public void setServiceKey(string service_key)

{

Recaptcha2captcha.captcha_service_key = service_key;

}

public void setSiteKey(string site_key)

{

this.site_key = site_key;

}

public void setPageUrl(string page_url)

{

this.page_url = page_url;

}

public string SendRequest() // HTTP POST

{

try

{

System.Net.ServicePointManager.Expect100Continue = false;

var request = (HttpWebRequest)WebRequest.Create("http://2captcha.com/in.php");

var postData = "key="+ Recaptcha2captcha.captcha_service_key +"&method=userrecaptcha&googlekey=" + this.site_key + "&page_url=" + this.page_url;

var data = Encoding.ASCII.GetBytes(postData);

request.Method = "POST";

request.ContentType = "application/x-www-form-urlencoded";

request.ContentLength = data.Length;

using (var stream = request.GetRequestStream())

{

stream.Write(data, 0, data.Length);

}

var response = (HttpWebResponse)request.GetResponse();

var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();

response.Close();

if (responseString.Contains("OK|"))

{

return responseString;

}

else

{

return "2captcha service return error. Error code:" + responseString;

}

catch (Exception e)

{

return e.Message;

}

public string SubmitForm(string RecaptchaResponseToken) // HTTP POST

{

// var page_url = "http://testing-ground.scraping.pro/recaptcha";

try

{

System.Net.ServicePointManager.Expect100Continue = false;

var request = (HttpWebRequest)WebRequest.Create(this.page_url);

var postData = "submit=submin&g-recaptcha-response=" + RecaptchaResponseToken;

var data = Encoding.ASCII.GetBytes(postData);

request.Method = "POST";

request.ContentType = "application/x-www-form-urlencoded";

request.ContentLength = data.Length;

using (var stream = request.GetRequestStream())

{

stream.Write(data, 0, data.Length);

}

var response = (HttpWebResponse)request.GetResponse();

var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();

response.Close();

return responseString;

}

catch (Exception e)

{

return e.Message;

}

// the request to retrieve g-recaptcha-response token from 2captcha service

public string getToken(string captcha_id) // HTTP GET

{

WebClient webClient = new WebClient();

webClient.QueryString.Add("key", Recaptcha2captcha.captcha_service_key);

webClient.QueryString.Add("action", "get");

webClient.QueryString.Add("id", captcha_id);

return webClient.DownloadString("http://2captcha.com/res.php");

}

// validate site with returned token thru proxy.php

public string getValidate(string token)

{

WebClient webClient = new WebClient();

webClient.QueryString.Add("response", token);

return webClient.DownloadString("http://testing-ground.scraping.pro/proxy.php");

}

class Program

{

static void Main(string[] args)

{

if (args.Length != 1)

{

System.Console.WriteLine("Usage: main.exe <2captcha_service_key>");

return;

}

string service_key = args[0];

// Console.WriteLine("2captcha service key: " + service_key);

Recaptcha2captcha service = new Recaptcha2captcha();

// we set 2captcha service key and target google site_key

service.setServiceKey(service_key);

service.setSiteKey("6Lf5CQkTAAAAAKA-kgNm9mV6sgqpGmRmRMFJYMz8");

serivce.service.setPageUrl("http://testing-ground.scraping.pro/recaptcha");

var resp = service.SendRequest();

var gcaptchaToken = "";

Console.WriteLine(resp.Substring( 3, resp.Length-3));

if (resp.Contains("OK|")){

// loop till the service solves captcha and gets g-recaptcha-response token

var i=0;

while (i++ <= 20)

{

System.Threading.Thread.Sleep(5000); // sleep 5 seconds

Console.WriteLine("Captcha is being solved for {0} seconds", i*5);

gcaptchaToken = service.getToken(resp.Substring( 3, resp.Length-3));

if (gcaptchaToken.Contains("OK|"))

{

break;

}

if (gcaptchaToken.Contains("OK|"))

{

var RecaptchaResponseToken = gcaptchaToken.Substring(3, gcaptchaToken.Length-3);

Console.WriteLine("g-recaptcha-response token: " + RecaptchaResponseToken );

// make google to validate g-recaptcha-response token

var iSvalid = service.getValidate(RecaptchaResponseToken);

Console.WriteLine("Token is validated by google: " + iSvalid );

// submit form to the target site

var SubmitFormResp = service.SubmitForm(RecaptchaResponseToken);

Console.WriteLine("Submit form return: " + SubmitFormResp );

} else {

Console.WriteLine("Captcha has not been solved. Error code: " + gcaptchaToken);

//Environment.Exit(0);

}

} else {

Console.WriteLine("Error: " + resp);

//Environment.Exit(0);

}

Console.Read();

}

3 Comments

Aleksey
Mar 02, 2017 @ 18:26

Please fix next typos in example:
1) return “2captcha service return error. Error code:”.responseString; -> + responseString
2) serivce.setPageUrl… -> service.service.setPageUrl
3) uncomment public string getValidate(string token)

- Igor Savinkin
  Mar 02, 2017 @ 18:31
  
  Thank you, Aleksey.
  
Nilesh
Sep 09, 2018 @ 10:06

How to develop captcha solving software ?

Web Scraping

web scraping, screen scraping, data parsing and other related things

2captcha service integration for solving recaptcha by C# code

3 Comments

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