Simple National Opting Query (by CNPJ) - C#

Question

I am implementing in C# a Consultation of Company Opting for the National Simple Tax Regime through this link http://www8.receita.fazenda.gov.br/SimplesNacional/Aplicacoes/ATBHE/ConsultaOptantes.app/ConsultarOpcao.aspx

I already have implemented another similar query (search the registration data of the informed CNPJ) and tried to base myself on the same search structure... but when I implement the POST in the cited URL a 404 error (not located) é retornado... I don’t know much about the WEB protocols so could someone help me? I have problems with Cookie and also with sending the data for consultation... I’m testing with a Recipe URL that returns the CAPTCHA, but I must have problems with this too...

    public class ConsultaCNPJSimplesNacional
{

    //public static int c=0;
    private readonly CookieContainer _cookies = new CookieContainer();
    private const String urlBaseReceitaFederalCNPJ = "http://www8.receita.fazenda.gov.br/SimplesNacional/Aplicacoes/ATBHE/ConsultaOptantes.app/";
    //private const String paginaValidacaoCNPJ = "ConsultarOpcao.aspx";
    private const String paginaPrincipalCNPJ = "ConsultarOpcao.aspx";
    private const String paginaCaptchaCNPJ = "http://www.receita.fazenda.gov.br/scripts/srf/intercepta/captcha.aspx?opt=image";


    public Bitmap GetCaptchaCNPJ()
    {
        String htmlResult;
        Bitmap retorno;

        using (var wc = new CookieAwareWebClient())
        {
            wc.SetCookieContainer(_cookies);
            wc.Headers[HttpRequestHeader.UserAgent] = "Mozilla/4.0 (compatible; Synapse)";
            wc.Headers[HttpRequestHeader.KeepAlive] = "300";
            htmlResult = wc.DownloadString(urlBaseReceitaFederalCNPJ + paginaPrincipalCNPJ);
        }
        if (htmlResult.Length > 0)
        {
            var wc2 = new CookieAwareWebClient();
            wc2.SetCookieContainer(_cookies);
            wc2.Headers[HttpRequestHeader.UserAgent] = "Mozilla/4.0 (compatible; Synapse)";
            wc2.Headers[HttpRequestHeader.KeepAlive] = "300";

            retorno = new System.Drawing.Bitmap(new System.IO.MemoryStream(wc2.DownloadData(paginaCaptchaCNPJ)));

            return retorno;

        }
        return null;
    }

    public String ConsultaCNPJ(string aCNPJ, string aCaptcha)
    {
        var request = (HttpWebRequest)WebRequest.Create(urlBaseReceitaFederalCNPJ + paginaPrincipalCNPJ);
        request.ProtocolVersion = HttpVersion.Version10;
        request.CookieContainer = _cookies;
        request.Method = "POST";



        string postData = "";
        postData = string.Format("{0}__EVENTTARGET={1}&", postData, "null");
        postData = string.Format("{0}__EVENTARGUMENT={1}&", postData, "null");
        postData = string.Format("{0}__VIEWSTATE={1}&", postData, "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");
        postData = string.Format("{0}__EVENTVALIDATION={1}&", postData, "/wEWBgLq/eloAqye/fEBAubugugBArTc7JALAoj16KgKAsPCk6ABUmPOXmbrPKdGe79cSZ5xd7+tpvEhZPqniHtlSzKz9g0=");
        postData = string.Format("{0}ctl00$ContentPlaceHolderConteudo$635896812039632962={1}&", postData, new Regex(@"[^\d]").Replace(aCNPJ, string.Empty));
        postData = string.Format("{0}ctl00$ContentPlaceHolderConteudo$HiddenField1={1}&", postData, "635896812039632962");
        postData = string.Format("{0}ctl00$ContentPlaceHolderConteudo$hddServidorCaptcha={1}&", postData, "pro");
        postData = string.Format("{0}ctl00$ContentPlaceHolderConteudo$txtTexto_captcha_serpro_gov_br={1}&", postData, aCaptcha);
        postData = string.Format("{0}ctl00$ContentPlaceHolderConteudo$btnConfirmar={1}&", postData, "Consultar");


        byte[] byteArray = Encoding.UTF8.GetBytes(postData);
        request.ContentType = "application/x-www-form-urlencoded";
        request.ContentLength = byteArray.Length;

        Stream dataStream = request.GetRequestStream();
        dataStream.Write(byteArray, 0, byteArray.Length);
        dataStream.Close();

        WebResponse response = request.GetResponse();
        StreamReader stHtml = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding("ISO-8859-1"));
        String retorno = stHtml.ReadToEnd();

        if (retorno.Contains("Verifique se o mesmo foi digitado corretamente"))
            throw new System.InvalidOperationException("O número do CNPJ não foi digitado corretamente");
        if (retorno.Contains("Erro na Consulta"))
            throw new System.InvalidOperationException("Os caracteres digitados não correspondem com a imagem");
        if (retorno.Contains("Esta página tem como objetivo permitir"))
            throw new System.InvalidOperationException("Erro não mapeado...");

        return retorno;
    }
}

Someone out there has already implemented or can help me implement this type of Query?

Answer 1

After a lot of head breaking and get help from a fellow professional in the WEB area I managed to reformulate the methods and get the desired result...

Below detailed and functional code...! PS.: It was failing when sending the parameters and also in passing the cookie containing the Captcha TOKEN...
Let it be an example to many others who have needed and given up on the way...

public class ConsultaCNPJSimplesNacional
{
    private string viewState, eventValidation, hiddenField1, servidorCaptcha, stringCookies, token = string.Empty, img = string.Empty;

    private const String urlBaseReceitaFederalCNPJ = "http://www8.receita.fazenda.gov.br/SimplesNacional/Aplicacoes/ATBHE/ConsultaOptantes.app/ConsultarOpcao.aspx";
    private const String paginaCaptchaCNPJ = "http://www8.receita.fazenda.gov.br/SimplesNacional/Aplicacoes/ATBHE/ConsultaOptantes.app/Captcha/Inicializa.ashx";

    /// <summary>
    /// Captura Captcha e também armazena valores de alguns parametros a serem enviados na Consulta
    /// </summary>
    /// <returns>Retorna BITMAP contendo imagem Captcha</returns>
    public Bitmap GetCaptchaCNPJ()
    {
        String htmlResult = string.Empty;
        Bitmap retorno = null;

        try
        {
            WebClient wc = new WebClient();

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

            //requisita valores das variaveis para armazenamento
            htmlResult = wc.DownloadString(urlBaseReceitaFederalCNPJ);

            if (htmlResult.Length > 0)
            {
                var doc = new HtmlDocument();
                doc.LoadHtml(htmlResult);


                servidorCaptcha = doc.DocumentNode.Descendants("input")
                                .First(i => i.Attributes["id"] != null &&
                                            i.Attributes["id"].Value == "hddServidorCaptcha")
                                .Attributes["value"].Value;

                viewState = doc.DocumentNode.Descendants("input")
                                .First(i => i.Attributes["id"] != null &&
                                            i.Attributes["id"].Value == "__VIEWSTATE")
                                .Attributes["value"].Value;

                eventValidation = doc.DocumentNode.Descendants("input")
                                .First(i => i.Attributes["id"] != null &&
                                            i.Attributes["id"].Value == "__EVENTVALIDATION")
                                .Attributes["value"].Value;

                hiddenField1 = doc.DocumentNode.Descendants("input")
                                .First(i => i.Attributes["id"] != null &&
                                            i.Attributes["id"].Value == "ctl00_ContentPlaceHolderConteudo_HiddenField1")
                                .Attributes["value"].Value;

                //requisita Captcha armazenando TOKEN a ser utilizado na Consulta
                htmlResult = wc.DownloadString(paginaCaptchaCNPJ);

                if (htmlResult.Length > 0)
                {
                    stringCookies = htmlResult;

                    string[] x = Regex.Split(htmlResult, "\",\"");

                    foreach (string s in x)
                    {
                        if (s.IndexOf("Token") >= 0)
                            token = new Regex(@"[^\d]").Replace(s, string.Empty);
                        else if (s.IndexOf("Dados") >= 0)
                            img = s.Substring(8);
                    }

                    if (img.Length > 0)
                    {
                        byte[] imageBytes = Convert.FromBase64String(img);
                        MemoryStream ms = new MemoryStream(imageBytes);

                        Image image = Image.FromStream(ms, true, true);

                        retorno = (Bitmap)image;
                    }
                }
            }

        }
        catch (Exception)
        {
            throw;
        }

        return retorno;

    }

    /// <summary>
    /// Faz Consulta do CNPJ informado pelo Usuário, verificando se o mesmo é Optante pelo Simples Nacional
    /// </summary>
    /// <param name="aCNPJ">CNPJ sem traços</param>
    /// <param name="aCaptcha">Conteúdo Captcha informado</param>
    /// <returns>Retorna Dados Cadastrais CNPJ e Regime Tributário Optado</returns>
    public List<KeyValuePair<string, string>> ConsultaCNPJ(string aCNPJ, string aCaptcha)
    {
        try
        {
            using (WebClient wc = new WebClient())
            {
                wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
                wc.Headers[HttpRequestHeader.Cookie] = "captcha_token=" + token;
                wc.Headers[HttpRequestHeader.Accept] = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
                wc.Headers[HttpRequestHeader.AcceptLanguage] = "pt-BR,pt;q=0.8,en-US;q=0.6,en;q=0.4";
                wc.Headers[HttpRequestHeader.AcceptEncoding] = "gzip, deflate";
                wc.Headers[HttpRequestHeader.Host] = "www8.receita.fazenda.gov.br";
                wc.Headers[HttpRequestHeader.UserAgent] = "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.152 Safari/537.36";


                byte[] response =
                wc.UploadValues(urlBaseReceitaFederalCNPJ, new NameValueCollection()
                {
                    { "__EVENTTARGET", "null" }, //conteudo estático, sempre nulo
                    { "__EVENTARGUMENT", "null" }, //conteudo estático, sempre nulo
                    { "__VIEWSTATE", viewState }, //conteudo armazenado durante consulta Captcha
                    { "__EVENTVALIDATION", eventValidation },//conteudo armazenado durante consulta Captcha
                    { string.Format("ctl00$ContentPlaceHolderConteudo${0}", hiddenField1), new Regex(@"[^\d]").Replace(aCNPJ, string.Empty) }, //identifica parametro CNPJ adicionando à propriedade NAME o conteudo dinâmico da varíavel armazenada durante captura Captcha
                    { "ctl00$ContentPlaceHolderConteudo$HiddenField1", hiddenField1 }, //conteudo armazenado durante consulta Captcha
                    { "ctl00$ContentPlaceHolderConteudo$hddServidorCaptcha", servidorCaptcha }, //conteudo armazenado durante consulta Captcha
                    { "ctl00$ContentPlaceHolderConteudo$txtTexto_captcha_serpro_gov_br", aCaptcha }, //Captcha digitado
                    { "ctl00$ContentPlaceHolderConteudo$btnConfirmar", "Consultar" } //conteúdo estático de consulta
                });

                string result = System.Text.Encoding.UTF8.GetString(response);

                //trata e retorna valores encontrados
                return TratarRetorno(result);
            }
        }
        catch (Exception)
        {
            throw;
        }
    }

    /// <summary>
    /// Captura os dados de Retorno do Site da Receita Federal
    /// </summary>
    /// <param name="resultado">STRING contendo Retorno da Consulta Realizada na Receita Federal</param>
    /// <returns>Retorna lista contendo Dados Cadastrais e Situação do CNPJ na Receita Federal</returns>
    private static List<KeyValuePair<string, string>> TratarRetorno(string resultado)
    {
        List<KeyValuePair<string, string>> retorno = new List<KeyValuePair<string, string>>();

        try
        {
            var doc = new HtmlDocument();
            doc.LoadHtml(resultado);

            #region ... Validação CAPTCHA ERROR...
            var itemError = (HtmlAgilityPack.HtmlNodeCollection)doc.DocumentNode.SelectNodes("//div[@id='ctl00_ContentPlaceHolderConteudo_pnlConsulta']");

            if (itemError != null)
            {
                foreach (HtmlAgilityPack.HtmlNode node in itemError)
                {
                    if (node.SelectNodes("//span[@id='ctl00_ContentPlaceHolderConteudo_lblErroCaptcha']") != null)
                        throw new Exception("Caracteres Captcha Inválidos.");
                }
            }
            #endregion

            #region ...Dados Empresa...
            var dadosEmpresa = (HtmlAgilityPack.HtmlNodeCollection)doc.DocumentNode.SelectNodes("//div[@id='ctl00_ContentPlaceHolderConteudo_Panel1']");

            if (dadosEmpresa != null)
            {
                foreach (HtmlAgilityPack.HtmlNode node in dadosEmpresa)
                {
                    foreach (HtmlAgilityPack.HtmlNode node2 in node.SelectNodes("//span[@id]"))
                    {
                        string attributeValue = node2.GetAttributeValue("id", "");
                        if (attributeValue == "ctl00_ContentPlaceHolderConteudo_lblCNPJ")
                        {
                            retorno.Add(new KeyValuePair<string, string>("CNPJ", node2.InnerText));
                        }
                        else if (attributeValue == "ctl00_ContentPlaceHolderConteudo_lblNomeEmpresa")
                        {
                            retorno.Add(new KeyValuePair<string, string>("EMPRESA", node2.InnerText));
                        }
                    }
                }

            }
            #endregion

            #region ...Situação do CNPJ...
            var dadosRetorno = (HtmlAgilityPack.HtmlNodeCollection)doc.DocumentNode.SelectNodes("//div[@id='ctl00_ContentPlaceHolderConteudo_Panel2']");

            if (dadosRetorno != null)
            {
                foreach (HtmlAgilityPack.HtmlNode node in dadosRetorno)
                {
                    foreach (HtmlAgilityPack.HtmlNode node2 in node.SelectNodes("//span[@id]"))
                    {
                        string attributeValue = node2.GetAttributeValue("id", "");
                        if (attributeValue == "ctl00_ContentPlaceHolderConteudo_lblSituacaoSimples")
                        {
                            retorno.Add(new KeyValuePair<string, string>("SITUAÇÃO", node2.InnerText));
                        }
                    }
                }
            }
            #endregion
        }
        catch (Exception)
        {
            throw;
        }

        return retorno;
    }
}