Cristian Romanescu

using System;
using System.Collections.Specialized;
using System.IO;
using System.Web;
using System.Net;
using log4net;


namespace ImportTool
{
  /// <summary>
  /// Description of ImportTool.
  /// </summary>
  public sealed class ImportUtilities
  {
    public static readonly ILog log = LogManager.GetLogger(typeof(ImportUtilities));

    public static void HttpUploadFile(string url, string file, string paramName, string contentType, NameValueCollection nvc) {
      log.Debug(string.Format("Uploading {0} to {1}", file, url));
      string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
      byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");

      HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url);
      wr.ContentType = "multipart/form-data; boundary=" + boundary;
      wr.Method = "POST";
      wr.KeepAlive = true;
      wr.Credentials = System.Net.CredentialCache.DefaultCredentials;

      Stream rs = wr.GetRequestStream();

      string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
      foreach (string key in nvc.Keys)
      {
        rs.Write(boundarybytes, 0, boundarybytes.Length);
        string formitem = string.Format(formdataTemplate, key, nvc[key]);
        byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
        rs.Write(formitembytes, 0, formitembytes.Length);
      }
      rs.Write(boundarybytes, 0, boundarybytes.Length);

      string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";
      string header = string.Format(headerTemplate, paramName, file, contentType);
      byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
      rs.Write(headerbytes, 0, headerbytes.Length);

      FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read);
      byte[] buffer = new byte[4096];
      int bytesRead = 0;
      while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0) {
        rs.Write(buffer, 0, bytesRead);
      }
      fileStream.Close();

      byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
      rs.Write(trailer, 0, trailer.Length);
      rs.Close();
      rs = null;

      WebResponse wresp = null;
      try {
        wresp = wr.GetResponse();
        Stream stream2 = wresp.GetResponseStream();
        StreamReader reader2 = new StreamReader(stream2);
      } catch(Exception ex) {
        log.Error("Error uploading file:" + file, ex);
        throw ex;
      } finally {
        if(wresp != null) {
          wresp.Close();
          wresp = null;
        }
        wr = null;
      }
    }
  }
}

// Sample usage:
 NameValueCollection nvc = new NameValueCollection();
    nvc.Add("id", "TTR");
    nvc.Add("btn-submit-photo", "Upload");
    HttpUploadFile("http://your.server.com/upload",
         @"C:\test\test.jpg", "file", "image/jpeg", nvc);