WebRequests Class

/*
 *  BigDataCorp 2012
 *  [2012_01_10] [ Marcello Lins ]
 *
 *   This Class is responsible for executing Web Requests and hold possible error messages.
 *   In order to make use of this Class, after instantiating it, the user have to set
 *   up the URL used for the request by using the Public Property : "URL". This URL
 *   will be used to create an HttpWebRequest Object.
 *
 *   There are also public properties that can be used to setup the request parameters
 *   such as timeout,referer,host and so on. Any other parameter that is not included here
 *   can be added without any future mess.
 *
 *   If the user needs the CookieContainer used on the requests to be reseted, he must implicitly
 *   call the ClearCookies method, that will create a new CookieContainer overwriting the old one.
 *
 *   After creating a request, and setting its parameters, the user can make use of methods such as
 *   "Get" and "Post", both returning the response of their requests.
 *
 *   There are Default Values for some Attributes of the request:
 *     . Timeout           = 8000 Miliseconds
 *     . Encoding          = "ISO-8859-1"
 *     . Connections Limit = 500
 *     . UserAgent         = Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/13.0.782.107 Safari/535.1
 *
 */

using System;
using System.Net;
using System.IO;
using BDC.BDCCommons;

namespace WebUtilsLib
{
    public class WebRequests
    {
        #region ** Private Attributes **

        // Private Attributes
        private CookieContainer     m_CookieJar         = null;
        private HttpWebRequest      m_HttpWebRequest    = null;
        private string              m_userAgent         = String.Empty;
        private string              m_contentType       = String.Empty;
        private string              m_host              = String.Empty;
        private string              m_encoding          = String.Empty;
        private string              m_referer           = String.Empty;
        private string              m_error             = String.Empty;
        private string              m_origin            = String.Empty;
        private string              m_acceptEncoding    = String.Empty;
        private int                 m_timeout           = 0;
        private int                 m_connectionsLimit  = 0;
        private bool                m_allowAutoRedirect = false ;
        private WebHeaderCollection m_requestHeaders    = null;

        // Error Logging Flag
        private bool                m_logOnError        = false;

        #endregion

        #region ** Public Properties **

        // Public Properties
        public HttpWebRequest InternalWebRequest
        {
            set { m_HttpWebRequest = value; }
        }

        /// <summary>
        /// UserAgent attribute
        /// Of the HttpWebRequest
        /// </summary>
        public string UserAgent
        {
            get { return m_userAgent;  }
            set { m_userAgent = value; }
        }

        /// <summary>
        /// Host attribute
        /// Of the HttpWebRequest
        /// </summary>
        public string Host
        {
            get { return m_host;  }
            set { m_host = value; }
        }

        /// <summary>
        /// ContentType attribute
        /// Of the HttpWebRequest
        /// </summary>
        public string ContentType
        {
            get { return m_contentType;  }
            set { m_contentType = value; }
        }

        /// <summary>
        /// Encoding parameter
        /// Of the HttpWebRequest
        /// </summary>
        public string Encoding
        {
            get { return m_encoding; }
            set { m_encoding = value; }
        }

        /// <summary>
        /// Referer attribute
        /// Of the HttpWebRequest
        /// </summary>
        public string Referer
        {
            get { return m_referer;  }
            set { m_referer = value; }
        }

        /// <summary>
        /// Timeout attribute
        /// Of the HttpWebRequest
        /// </summary>
        public int Timeout
        {
            get { return m_timeout;  }
            set { m_timeout = value; }
        }

        /// <summary>
        /// ConnectionsLimit
        /// attribute
        /// Of the HttpWebRequest
        /// </summary>
        public int ConnectionsLimit
        {
            get { return m_connectionsLimit;  }
            set { m_connectionsLimit = value; }
        }

        /// <summary>
        /// AllowAutoRedirect attribute
        /// Of the HttpWebRequest
        /// </summary>
        public bool AllowAutoRedirect
        {
            get { return m_allowAutoRedirect;  }
            set { m_allowAutoRedirect = value; }
        }

        /// <summary>
        /// Origin attribute
        /// Of the HttpWebRequest
        /// </summary>
        public string Origin
        {
            get { return m_origin;  }
            set { m_origin = value; }
        }

        /// <summary>
        /// AcceptEncoding
        /// attribute
        /// Of the HttpWebRequest
        /// </summary>
        public string AcceptEncoding
        {
            get { return m_acceptEncoding;  }
            set { m_acceptEncoding = value; }
        }

        /// <summary>
        /// Headers attribute
        /// of the HttpWebRequest
        /// </summary>
        public WebHeaderCollection Headers
        {
            get { return m_requestHeaders;  }
            set { m_requestHeaders = value; }
        }

        /// <summary>
        /// Message containing the
        /// last error that ocurred.
        /// Can be reseted by using ClearError
        /// Method
        /// </summary>
        public string Error
        {
            get { return m_error; }
        }

        /// <summary>
        /// Setter for LogOnError Attribute
        /// </summary>
        public bool LogErrorFlag
        {
            set { m_logOnError = value; }
        }
        #endregion

        /// <summary>
        /// Class Constructor
        /// </summary>
        /// <param name="LogOnError">Flag. If true then errors will be logged, else, logging is off</param>
        public WebRequests(bool LogOnError = false)
        {
            m_CookieJar = new CookieContainer();

            // Setting Default Values for some Attributes
            m_contentType      = "application/x-www-form-urlencoded";
            m_userAgent        = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/13.0.782.107 Safari/535.1";
            m_encoding         = "ISO-8859-1";
            m_timeout          = 8000;
            m_connectionsLimit = 500;
            m_logOnError       = LogOnError;
            m_requestHeaders   = new WebHeaderCollection();
        }

        #region ** Clearing Methods **

        /// <summary>
        /// Clear the content of the
        /// Cookie Container class used in
        /// the requests
        /// </summary>
        public void ClearCookies()
        {
            m_CookieJar = new CookieContainer();
        }

        /// <summary>
        /// Clears the last error variable
        /// </summary>
        public void ClearError()
        {
            m_error = String.Empty;
        }

        #endregion

        #region ** HttpWebRequests Methods **

        /// <summary>
        /// Executes a Get
        /// creating an HttpWebRequest
        /// object based on previously
        /// set attributes
        /// </summary>
        /// <returns>Response of the Request. Empty string if any error ocurred.</returns>
        public string Get(string url)
        {
            string response = String.Empty;

            // Checking for empty url
            if (String.IsNullOrEmpty(url))
            {
                throw new Exception("URL para o Request não foi configurada ou é nula.");
            }

            try
            {
                // Re-Creating Request Object to avoid exceptions
                m_HttpWebRequest = WebRequest.Create (url) as HttpWebRequest;

                m_HttpWebRequest.CookieContainer              = m_CookieJar;
                m_HttpWebRequest.Method                       = "GET";
                m_HttpWebRequest.UserAgent                    = m_userAgent;
                m_HttpWebRequest.ServicePoint.ConnectionLimit = m_connectionsLimit;
                m_HttpWebRequest.Timeout                      = m_timeout;
                m_HttpWebRequest.ContentType                  = m_contentType;
                m_HttpWebRequest.Referer                      = m_referer;
                m_HttpWebRequest.AllowAutoRedirect            = m_allowAutoRedirect;

                if (!String.IsNullOrEmpty(m_host))
                {
                    m_HttpWebRequest.Host = m_host;
                }

                // Execute web request and wait for response
                using (HttpWebResponse resp = (HttpWebResponse) m_HttpWebRequest.GetResponse())
                {
                  response= new StreamReader(resp.GetResponseStream()).ReadToEnd();
                }
            }
            catch (Exception ex)
            {
                m_error  = ex.ToString();
                response = String.Empty;

                if (m_logOnError)
                    LogWriter.Error(ex);
            }

            return response;
        }

        /// <summary>
        /// Executes a POST
        /// creating an HttpWebRequest
        /// object based on previously
        /// set attributes.
        /// </summary>
        /// <param name="postData">Parameters the Post Request</param>
        /// <returns>Response of the Request. Empty string if any error ocurred.</returns>
        public string Post (string url,string postData)
        {
            string response = String.Empty;

            // Checking for empty url
            if (String.IsNullOrEmpty(url))
            {
                throw new Exception("URL para o Request não foi configurada ou é nula.");
            }

            try
            {
                // Re-Creating Request Object to avoid exceptions
                m_HttpWebRequest = WebRequest.Create (url) as HttpWebRequest;

                m_HttpWebRequest.Method                       = "POST";
                m_HttpWebRequest.CookieContainer              = m_CookieJar;
                m_HttpWebRequest.UserAgent                    = m_userAgent;
                m_HttpWebRequest.ServicePoint.ConnectionLimit = m_connectionsLimit;
                m_HttpWebRequest.Timeout                      = m_timeout;
                m_HttpWebRequest.ContentType                  = m_contentType;
                m_HttpWebRequest.Referer                      = m_referer;
                m_HttpWebRequest.AllowAutoRedirect            = m_allowAutoRedirect;

                if (!String.IsNullOrEmpty(m_host))
                    m_HttpWebRequest.Host = m_host;

                // Counting the bytes to send
                byte[] bytes                   = System.Text.Encoding.GetEncoding(m_encoding).GetBytes(postData);
                int bytesSize                  = bytes.Length;
                m_HttpWebRequest.ContentLength = bytesSize;

                // Send Request
                using (var requestStream = m_HttpWebRequest.GetRequestStream())
                {
                    requestStream.Write(bytes, 0, bytesSize);
                }

                // Get the Response
                using (WebResponse webResponse = m_HttpWebRequest.GetResponse())
                {
                    if (webResponse != null)
                    {
                        // Read the Content of the response
                        using (var responseStream = webResponse.GetResponseStream())
                        {
                            using (StreamReader Reader = new StreamReader(responseStream, System.Text.Encoding.GetEncoding(m_encoding)))
                            {
                                response = Reader.ReadToEnd().Trim();
                            }
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                m_error  = ex.ToString();
                response = String.Empty;

                if(m_logOnError)
                    LogWriter.Error(ex);
            }

            return response;
        }

        #endregion
    }
}