Marquim!!!!

opa.cs

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

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            CookieContainer cc;
            var client = (HttpWebRequest) HttpWebRequest.Create(@"http://www.saoluizdelivery.com.br/ajaxpro/IKCLojaMaster.bemvindo,MercadinhoSaoLuiz.ashx");

            client.Method = "post";
            client.ContentLength = "{\"cep\":\"60020-270\"}".Length;
            client.Referer = "http://www.saoluizdelivery.com.br/bemvindo.aspx";
            client.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.4 (KHTML, like Gecko) Chrome/22.0.1229.79 Safari/537.4";
            client.Host = "www.saoluizdelivery.com.br";
            client.ContentType = "text/plain; charset=UTF-8";
            client.ContentType = "application/x-www-form-urlencoded";
            client.Headers.Add("X-Requested-With", "XMLHttpRequest");
            client.Headers.Add("X-AjaxPro-Method", "EntrarLoja");

            using (var stream = client.GetRequestStream())
            {
                using (var str = new StreamWriter(stream))
                {
                    str.Write("{\"cep\":\"60020-270\"}");
                    str.Close();
                }
                stream.Close();
            }
            client.CookieContainer = cc = new CookieContainer();

            WebResponse webResponse = null;
            try
            {
                webResponse = client.GetResponse();
                using (var str = new StreamReader(webResponse.GetResponseStream()))
                {
                    Console.WriteLine(str.ReadToEnd());
                }
            }
            catch (WebException e)
            {
                using (var str = new StreamReader(webResponse.GetResponseStream()))
                {
                    Console.WriteLine(str.ReadToEnd());
                }
            }

            client = (HttpWebRequest)HttpWebRequest.Create(@"http://www.saoluizdelivery.com.br/");
            client.CookieContainer = cc;

            webResponse = client.GetResponse();

            try
            {
                webResponse = client.GetResponse();
                using (var str = new StreamReader(webResponse.GetResponseStream()))
                {
                    Console.WriteLine(str.ReadToEnd());
                }
            }
            catch (WebException e)
            {
                using (var str = new StreamReader(webResponse.GetResponseStream()))
                {
                    Console.WriteLine(str.ReadToEnd());
                }
            }

            Console.Read();
        }
    }
}

opa.rb

require "net/http"
require "uri"

uri = URI.parse("http://www.saoluizdelivery.com.br/ajaxpro/IKCLojaMaster.bemvindo,MercadinhoSaoLuiz.ashx")

# Full control
http = Net::HTTP.new(uri.host, uri.port)

request = Net::HTTP::Post.new(uri.request_uri)
request.set_form_data({"cep" => "60020-270"})
request.add_field "X-AjaxPro-Method" , "EntrarLoja"

response = http.request(request)
puts request.method
#for f in response.msg
    puts response.get_fields('set-cookie')
#end

#h1 = open("http://www.saoluizdelivery.com.br/ajaxpro/IKCLojaMaster.bemvindo,MercadinhoSaoLuiz.ashx")
#Clipboard.copy h1.meta["set-cookie"]