mcs/class/System/System.Net/WebClient.cs

   1 //
   2 // System.Net.WebClient
   3 //
   4 // Authors:
   5 //      Lawrence Pit (loz@cable.a2000.nl)
   6 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   7 //      Atsushi Enomoto (atsushi@ximian.com)
   8 //      Miguel de Icaza (miguel@ximian.com)
   9 //
  10 // Copyright 2003 Ximian, Inc. (http://www.ximian.com)
  11 // Copyright 2006, 2010 Novell, Inc. (http://www.novell.com)
  12 //
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33 //
  34 // Notes on CancelAsync and Async methods:
  35 //
  36 //    WebClient.CancelAsync is implemented by calling Thread.Interrupt
  37 //    in our helper thread.   The various async methods have to cancel
  38 //    any ongoing requests by calling request.Abort () at that point.
  39 //    In a few places (UploadDataCore, UploadValuesCore,
  40 //    UploadFileCore) we catch the ThreadInterruptedException and
  41 //    abort the request there.
  42 //
  43 //    Higher level routines (the async callbacks) also need to catch
  44 //    the exception and raise the OnXXXXCompleted events there with
  45 //    the "canceled" flag set to true.
  46 //
  47 //    In a few other places where these helper routines are not used
  48 //    (OpenReadAsync for example) catching the ThreadAbortException
  49 //    also must abort the request.
  50 //
  51 //    The Async methods currently differ in their implementation from
  52 //    the .NET implementation in that we manually catch any other
  53 //    exceptions and correctly raise the OnXXXXCompleted passing the
  54 //    Exception that caused the problem.   The .NET implementation
  55 //    does not seem to have a mechanism to flag errors that happen
  56 //    during downloads though.    We do this because we still need to
  57 //    catch the exception on these helper threads, or we would
  58 //    otherwise kill the application (on the 2.x profile, uncaught
  59 //    exceptions in threads terminate the application).
  60 //
  61 using System;
  62 using System.Collections.Specialized;
  63 using System.ComponentModel;
  64 using System.IO;
  65 using System.Runtime.InteropServices;
  66 using System.Runtime.Serialization;
  67 using System.Text;
  68 using System.Threading;
  69 using System.Net.Cache;
  70
  71 namespace System.Net
  72 {
  73         [ComVisible(true)]
  74         public class WebClient : Component
  75         {
  76                 static readonly string urlEncodedCType = "application/x-www-form-urlencoded";
  77                 static byte [] hexBytes;
  78                 ICredentials credentials;
  79                 WebHeaderCollection headers;
  80                 WebHeaderCollection responseHeaders;
  81                 Uri baseAddress;
  82                 string baseString;
  83                 NameValueCollection queryString;
  84                 bool is_busy;
  85                 bool async;
  86                 bool proxySet = false;
  87                 Thread async_thread;
  88                 Encoding encoding = Encoding.Default;
  89                 IWebProxy proxy;
  90 //              RequestCachePolicy cache_policy;
  91
  92                 // Constructors
  93                 static WebClient ()
  94                 {
  95                         hexBytes = new byte [16];
  96                         int index = 0;
  97                         for (int i = '0'; i <= '9'; i++, index++)
  98                                 hexBytes [index] = (byte) i;
  99
 100                         for (int i = 'a'; i <= 'f'; i++, index++)
 101                                 hexBytes [index] = (byte) i;
 102                 }
 103
 104                 public WebClient ()
 105                 {
 106                 }
 107
 108                 // Properties
 109
 110                 public string BaseAddress {
 111                         get {
 112                                 if (baseString == null) {
 113                                         if (baseAddress == null)
 114                                                 return string.Empty;
 115                                 }
 116
 117                                 baseString = baseAddress.ToString ();
 118                                 return baseString;
 119                         }
 120
 121                         set {
 122                                 if (value == null || value.Length == 0) {
 123                                         baseAddress = null;
 124                                 } else {
 125                                         baseAddress = new Uri (value);
 126                                 }
 127                         }
 128                 }
 129
 130                 static Exception GetMustImplement ()
 131                 {
 132                         return new NotImplementedException ();
 133                 }
 134
 135                 [MonoTODO ("Value can be set but is currently ignored")]
 136                 public RequestCachePolicy CachePolicy
 137                 {
 138                         get {
 139                                 throw GetMustImplement ();
 140                         }
 141                         set { /*cache_policy = value;*/ }
 142                 }
 143
 144                 [MonoTODO ("Value can be set but is ignored")]
 145                 public bool UseDefaultCredentials
 146                 {
 147                         get {
 148                                 throw GetMustImplement ();
 149                         }
 150                         set {
 151                                 // This makes no sense in mono
 152                         }
 153                 }
 154
 155                 public ICredentials Credentials {
 156                         get { return credentials; }
 157                         set { credentials = value; }
 158                 }
 159
 160                 public WebHeaderCollection Headers {
 161                         get {
 162                                 if (headers == null)
 163                                         headers = new WebHeaderCollection ();
 164
 165                                 return headers;
 166                         }
 167                         set { headers = value; }
 168                 }
 169
 170                 public NameValueCollection QueryString {
 171                         get {
 172                                 if (queryString == null)
 173                                         queryString = new NameValueCollection ();
 174
 175                                 return queryString;
 176                         }
 177                         set { queryString = value; }
 178                 }
 179
 180                 public WebHeaderCollection ResponseHeaders {
 181                         get { return responseHeaders; }
 182                 }
 183
 184                 public Encoding Encoding {
 185                         get { return encoding; }
 186                         set {
 187                                 if (value == null)
 188                                         throw new ArgumentNullException ("Encoding");
 189                                 encoding = value;
 190                         }
 191                 }
 192
 193                 public IWebProxy Proxy {
 194                         get {
 195                                 if (!proxySet)
 196                                         return WebRequest.DefaultWebProxy;
 197
 198                                 return proxy;
 199                         }
 200                         set {
 201                                 proxy = value;
 202                                 proxySet = true;
 203                         }
 204                 }
 205
 206                 public bool IsBusy {
 207                         get { return is_busy; }
 208                 }
 209                 // Methods
 210
 211                 void CheckBusy ()
 212                 {
 213                         if (IsBusy)
 214                                 throw new NotSupportedException ("WebClient does not support conccurent I/O operations.");
 215                 }
 216
 217                 void SetBusy ()
 218                 {
 219                         lock (this) {
 220                                 CheckBusy ();
 221                                 is_busy = true;
 222                         }
 223                 }
 224
 225                 //   DownloadData
 226
 227                 public byte [] DownloadData (string address)
 228                 {
 229                         if (address == null)
 230                                 throw new ArgumentNullException ("address");
 231
 232                         return DownloadData (CreateUri (address));
 233                 }
 234
 235                 public byte [] DownloadData (Uri address)
 236                 {
 237                         if (address == null)
 238                                 throw new ArgumentNullException ("address");
 239
 240                         try {
 241                                 SetBusy ();
 242                                 async = false;
 243                                 return DownloadDataCore (address, null);
 244                         } finally {
 245                                 is_busy = false;
 246                         }
 247                 }
 248
 249                 byte [] DownloadDataCore (Uri address, object userToken)
 250                 {
 251                         WebRequest request = null;
 252
 253                         try {
 254                                 request = SetupRequest (address);
 255                                 return ReadAll (request, userToken);
 256                         } catch (ThreadInterruptedException){
 257                                 if (request != null)
 258                                         request.Abort ();
 259                                 throw;
 260                         } catch (WebException) {
 261                                 throw;
 262                         } catch (Exception ex) {
 263                                 throw new WebException ("An error occurred " +
 264                                         "performing a WebClient request.", ex);
 265                         }
 266                 }
 267
 268                 //   DownloadFile
 269
 270                 public void DownloadFile (string address, string fileName)
 271                 {
 272                         if (address == null)
 273                                 throw new ArgumentNullException ("address");
 274
 275                         DownloadFile (CreateUri (address), fileName);
 276                 }
 277
 278                 public void DownloadFile (Uri address, string fileName)
 279                 {
 280                         if (address == null)
 281                                 throw new ArgumentNullException ("address");
 282                         if (fileName == null)
 283                                 throw new ArgumentNullException ("fileName");
 284
 285                         try {
 286                                 SetBusy ();
 287                                 async = false;
 288                                 DownloadFileCore (address, fileName, null);
 289                         } catch (WebException) {
 290                                 throw;
 291                         } catch (Exception ex) {
 292                                 throw new WebException ("An error occurred " +
 293                                         "performing a WebClient request.", ex);
 294                         } finally {
 295                                 is_busy = false;
 296                         }
 297                 }
 298
 299                 void DownloadFileCore (Uri address, string fileName, object userToken)
 300                 {
 301                         WebRequest request = null;
 302
 303                         using (FileStream f = new FileStream (fileName, FileMode.Create)) {
 304                                 try {
 305                                         request = SetupRequest (address);
 306                                         WebResponse response = GetWebResponse (request);
 307                                         Stream st = response.GetResponseStream ();
 308
 309                                         int cLength = (int) response.ContentLength;
 310                                         int length = (cLength <= -1 || cLength > 32*1024) ? 32*1024 : cLength;
 311                                         byte [] buffer = new byte [length];
 312
 313                                         int nread = 0;
 314                                         long notify_total = 0;
 315                                         while ((nread = st.Read (buffer, 0, length)) != 0){
 316                                                 if (async){
 317                                                         notify_total += nread;
 318                                                         OnDownloadProgressChanged (
 319                                                                 new DownloadProgressChangedEventArgs (notify_total, response.ContentLength, userToken));
 320
 321                                                 }
 322                                                 f.Write (buffer, 0, nread);
 323                                         }
 324                                 } catch (ThreadInterruptedException){
 325                                         if (request != null)
 326                                                 request.Abort ();
 327                                         throw;
 328                                 }
 329                         }
 330                 }
 331
 332                 //   OpenRead
 333
 334                 public Stream OpenRead (string address)
 335                 {
 336                         if (address == null)
 337                                 throw new ArgumentNullException ("address");
 338                         return OpenRead (CreateUri (address));
 339                 }
 340
 341                 public Stream OpenRead (Uri address)
 342                 {
 343                         if (address == null)
 344                                 throw new ArgumentNullException ("address");
 345
 346                         WebRequest request = null;
 347                         try {
 348                                 SetBusy ();
 349                                 async = false;
 350                                 request = SetupRequest (address);
 351                                 WebResponse response = GetWebResponse (request);
 352                                 return response.GetResponseStream ();
 353                         } catch (WebException) {
 354                                 throw;
 355                         } catch (Exception ex) {
 356                                 throw new WebException ("An error occurred " +
 357                                         "performing a WebClient request.", ex);
 358                         } finally {
 359                                 is_busy = false;
 360                         }
 361                 }
 362
 363                 //   OpenWrite
 364
 365                 public Stream OpenWrite (string address)
 366                 {
 367                         if (address == null)
 368                                 throw new ArgumentNullException ("address");
 369
 370                         return OpenWrite (CreateUri (address));
 371                 }
 372
 373                 public Stream OpenWrite (string address, string method)
 374                 {
 375                         if (address == null)
 376                                 throw new ArgumentNullException ("address");
 377
 378                         return OpenWrite (CreateUri (address), method);
 379                 }
 380
 381                 public Stream OpenWrite (Uri address)
 382                 {
 383                         return OpenWrite (address, (string) null);
 384                 }
 385
 386                 public Stream OpenWrite (Uri address, string method)
 387                 {
 388                         if (address == null)
 389                                 throw new ArgumentNullException ("address");
 390
 391                         try {
 392                                 SetBusy ();
 393                                 async = false;
 394                                 WebRequest request = SetupRequest (address, method, true);
 395                                 return request.GetRequestStream ();
 396                         } catch (WebException) {
 397                                 throw;
 398                         } catch (Exception ex) {
 399                                 throw new WebException ("An error occurred " +
 400                                         "performing a WebClient request.", ex);
 401                         } finally {
 402                                 is_busy = false;
 403                         }
 404                 }
 405
 406                 private string DetermineMethod (Uri address, string method, bool is_upload)
 407                 {
 408                         if (method != null)
 409                                 return method;
 410
 411                         if (address.Scheme == Uri.UriSchemeFtp)
 412                                 return (is_upload) ? "STOR" : "RETR";
 413
 414                         return (is_upload) ? "POST" : "GET";
 415                 }
 416
 417                 //   UploadData
 418
 419                 public byte [] UploadData (string address, byte [] data)
 420                 {
 421                         if (address == null)
 422                                 throw new ArgumentNullException ("address");
 423
 424                         return UploadData (CreateUri (address), data);
 425                 }
 426
 427                 public byte [] UploadData (string address, string method, byte [] data)
 428                 {
 429                         if (address == null)
 430                                 throw new ArgumentNullException ("address");
 431
 432                         return UploadData (CreateUri (address), method, data);
 433                 }
 434
 435                 public byte [] UploadData (Uri address, byte [] data)
 436                 {
 437                         return UploadData (address, (string) null, data);
 438                 }
 439
 440                 public byte [] UploadData (Uri address, string method, byte [] data)
 441                 {
 442                         if (address == null)
 443                                 throw new ArgumentNullException ("address");
 444                         if (data == null)
 445                                 throw new ArgumentNullException ("data");
 446
 447                         try {
 448                                 SetBusy ();
 449                                 async = false;
 450                                 return UploadDataCore (address, method, data, null);
 451                         } catch (WebException) {
 452                                 throw;
 453                         } catch (Exception ex) {
 454                                 throw new WebException ("An error occurred " +
 455                                         "performing a WebClient request.", ex);
 456                         } finally {
 457                                 is_busy = false;
 458                         }
 459                 }
 460
 461                 byte [] UploadDataCore (Uri address, string method, byte [] data, object userToken)
 462                 {
 463                         WebRequest request = SetupRequest (address, method, true);
 464                         try {
 465                                 int contentLength = data.Length;
 466                                 request.ContentLength = contentLength;
 467                                 using (Stream stream = request.GetRequestStream ()) {
 468                                         stream.Write (data, 0, contentLength);
 469                                 }
 470
 471                                 return ReadAll (request, userToken);
 472                         } catch (ThreadInterruptedException){
 473                                 if (request != null)
 474                                         request.Abort ();
 475                                 throw;
 476                         }
 477                 }
 478
 479                 //   UploadFile
 480
 481                 public byte [] UploadFile (string address, string fileName)
 482                 {
 483                         if (address == null)
 484                                 throw new ArgumentNullException ("address");
 485
 486                         return UploadFile (CreateUri (address), fileName);
 487                 }
 488
 489                 public byte [] UploadFile (Uri address, string fileName)
 490                 {
 491                         return UploadFile (address, (string) null, fileName);
 492                 }
 493
 494                 public byte [] UploadFile (string address, string method, string fileName)
 495                 {
 496                         return UploadFile (CreateUri (address), method, fileName);
 497                 }
 498
 499                 public byte [] UploadFile (Uri address, string method, string fileName)
 500                 {
 501                         if (address == null)
 502                                 throw new ArgumentNullException ("address");
 503                         if (fileName == null)
 504                                 throw new ArgumentNullException ("fileName");
 505
 506                         try {
 507                                 SetBusy ();
 508                                 async = false;
 509                                 return UploadFileCore (address, method, fileName, null);
 510                         } catch (WebException) {
 511                                 throw;
 512                         } catch (Exception ex) {
 513                                 throw new WebException ("An error occurred " +
 514                                         "performing a WebClient request.", ex);
 515                         } finally {
 516                                 is_busy = false;
 517                         }
 518                 }
 519
 520                 byte [] UploadFileCore (Uri address, string method, string fileName, object userToken)
 521                 {
 522                         string fileCType = Headers ["Content-Type"];
 523                         if (fileCType != null) {
 524                                 string lower = fileCType.ToLower ();
 525                                 if (lower.StartsWith ("multipart/"))
 526                                         throw new WebException ("Content-Type cannot be set to a multipart" +
 527                                                                 " type for this request.");
 528                         } else {
 529                                 fileCType = "application/octet-stream";
 530                         }
 531
 532                         bool needs_boundary = (method != "PUT"); // only verified case so far
 533                         string boundary = null;
 534                         if (needs_boundary) {
 535                                 boundary = "------------" + DateTime.Now.Ticks.ToString ("x");
 536                                 Headers ["Content-Type"] = String.Format ("multipart/form-data; boundary={0}", boundary);
 537                         }
 538                         Stream reqStream = null;
 539                         Stream fStream = null;
 540                         byte [] resultBytes = null;
 541
 542                         fileName = Path.GetFullPath (fileName);
 543
 544                         WebRequest request = null;
 545                         try {
 546                                 fStream = File.OpenRead (fileName);
 547                                 request = SetupRequest (address, method, true);
 548                                 reqStream = request.GetRequestStream ();
 549                                 byte [] bytes_boundary = null;
 550                                 if (needs_boundary) {
 551                                         bytes_boundary = Encoding.ASCII.GetBytes (boundary);
 552                                         reqStream.WriteByte ((byte) '-');
 553                                         reqStream.WriteByte ((byte) '-');
 554                                         reqStream.Write (bytes_boundary, 0, bytes_boundary.Length);
 555                                         reqStream.WriteByte ((byte) '\r');
 556                                         reqStream.WriteByte ((byte) '\n');
 557                                         string partHeaders = String.Format ("Content-Disposition: form-data; " +
 558                                                                             "name=\"file\"; filename=\"{0}\"\r\n" +
 559                                                                             "Content-Type: {1}\r\n\r\n",
 560                                                                             Path.GetFileName (fileName), fileCType);
 561
 562                                         byte [] partHeadersBytes = Encoding.UTF8.GetBytes (partHeaders);
 563                                         reqStream.Write (partHeadersBytes, 0, partHeadersBytes.Length);
 564                                 }
 565                                 int nread;
 566                                 byte [] buffer = new byte [4096];
 567                                 while ((nread = fStream.Read (buffer, 0, 4096)) != 0)
 568                                         reqStream.Write (buffer, 0, nread);
 569
 570                                 if (needs_boundary) {
 571                                         reqStream.WriteByte ((byte) '\r');
 572                                         reqStream.WriteByte ((byte) '\n');
 573                                         reqStream.WriteByte ((byte) '-');
 574                                         reqStream.WriteByte ((byte) '-');
 575                                         reqStream.Write (bytes_boundary, 0, bytes_boundary.Length);
 576                                         reqStream.WriteByte ((byte) '-');
 577                                         reqStream.WriteByte ((byte) '-');
 578                                         reqStream.WriteByte ((byte) '\r');
 579                                         reqStream.WriteByte ((byte) '\n');
 580                                 }
 581                                 reqStream.Close ();
 582                                 reqStream = null;
 583                                 resultBytes = ReadAll (request, userToken);
 584                         } catch (ThreadInterruptedException){
 585                                 if (request != null)
 586                                         request.Abort ();
 587                                 throw;
 588                         } finally {
 589                                 if (fStream != null)
 590                                         fStream.Close ();
 591
 592                                 if (reqStream != null)
 593                                         reqStream.Close ();
 594                         }
 595
 596                         return resultBytes;
 597                 }
 598
 599                 public byte[] UploadValues (string address, NameValueCollection data)
 600                 {
 601                         if (address == null)
 602                                 throw new ArgumentNullException ("address");
 603
 604                         return UploadValues (CreateUri (address), data);
 605                 }
 606
 607                 public byte[] UploadValues (string address, string method, NameValueCollection data)
 608                 {
 609                         if (address == null)
 610                                 throw new ArgumentNullException ("address");
 611                         return UploadValues (CreateUri (address), method, data);
 612                 }
 613
 614                 public byte[] UploadValues (Uri address, NameValueCollection data)
 615                 {
 616                         return UploadValues (address, (string) null, data);
 617                 }
 618
 619                 public byte[] UploadValues (Uri address, string method, NameValueCollection data)
 620                 {
 621                         if (address == null)
 622                                 throw new ArgumentNullException ("address");
 623                         if (data == null)
 624                                 throw new ArgumentNullException ("data");
 625
 626                         try {
 627                                 SetBusy ();
 628                                 async = false;
 629                                 return UploadValuesCore (address, method, data, null);
 630                         } catch (WebException) {
 631                                 throw;
 632                         } catch (Exception ex) {
 633                                 throw new WebException ("An error occurred " +
 634                                         "performing a WebClient request.", ex);
 635                         } finally {
 636                                 is_busy = false;
 637                         }
 638                 }
 639
 640                 byte[] UploadValuesCore (Uri uri, string method, NameValueCollection data, object userToken)
 641                 {
 642                         string cType = Headers ["Content-Type"];
 643                         if (cType != null && String.Compare (cType, urlEncodedCType, true) != 0)
 644                                 throw new WebException ("Content-Type header cannot be changed from its default " +
 645                                                         "value for this request.");
 646
 647                         Headers ["Content-Type"] = urlEncodedCType;
 648                         WebRequest request = SetupRequest (uri, method, true);
 649                         try {
 650                                 MemoryStream tmpStream = new MemoryStream ();
 651                                 foreach (string key in data) {
 652                                         byte [] bytes = Encoding.UTF8.GetBytes (key);
 653                                         UrlEncodeAndWrite (tmpStream, bytes);
 654                                         tmpStream.WriteByte ((byte) '=');
 655                                         bytes = Encoding.UTF8.GetBytes (data [key]);
 656                                         UrlEncodeAndWrite (tmpStream, bytes);
 657                                         tmpStream.WriteByte ((byte) '&');
 658                                 }
 659
 660                                 int length = (int) tmpStream.Length;
 661                                 if (length > 0)
 662                                         tmpStream.SetLength (--length); // remove trailing '&'
 663
 664                                 byte [] buf = tmpStream.GetBuffer ();
 665                                 request.ContentLength = length;
 666                                 using (Stream rqStream = request.GetRequestStream ()) {
 667                                         rqStream.Write (buf, 0, length);
 668                                 }
 669                                 tmpStream.Close ();
 670
 671                                 return ReadAll (request, userToken);
 672                         } catch (ThreadInterruptedException) {
 673                                 request.Abort ();
 674                                 throw;
 675                         }
 676                 }
 677
 678                 public string DownloadString (string address)
 679                 {
 680                         if (address == null)
 681                                 throw new ArgumentNullException ("address");
 682
 683                         return encoding.GetString (DownloadData (CreateUri (address)));
 684                 }
 685
 686                 public string DownloadString (Uri address)
 687                 {
 688                         if (address == null)
 689                                 throw new ArgumentNullException ("address");
 690
 691                         return encoding.GetString (DownloadData (CreateUri (address)));
 692                 }
 693
 694                 public string UploadString (string address, string data)
 695                 {
 696                         if (address == null)
 697                                 throw new ArgumentNullException ("address");
 698                         if (data == null)
 699                                 throw new ArgumentNullException ("data");
 700
 701                         byte [] resp = UploadData (address, encoding.GetBytes (data));
 702                         return encoding.GetString (resp);
 703                 }
 704
 705                 public string UploadString (string address, string method, string data)
 706                 {
 707                         if (address == null)
 708                                 throw new ArgumentNullException ("address");
 709                         if (data == null)
 710                                 throw new ArgumentNullException ("data");
 711
 712                         byte [] resp = UploadData (address, method, encoding.GetBytes (data));
 713                         return encoding.GetString (resp);
 714                 }
 715
 716                 public string UploadString (Uri address, string data)
 717                 {
 718                         if (address == null)
 719                                 throw new ArgumentNullException ("address");
 720                         if (data == null)
 721                                 throw new ArgumentNullException ("data");
 722
 723                         byte [] resp = UploadData (address, encoding.GetBytes (data));
 724                         return encoding.GetString (resp);
 725                 }
 726
 727                 public string UploadString (Uri address, string method, string data)
 728                 {
 729                         if (address == null)
 730                                 throw new ArgumentNullException ("address");
 731                         if (data == null)
 732                                 throw new ArgumentNullException ("data");
 733
 734                         byte [] resp = UploadData (address, method, encoding.GetBytes (data));
 735                         return encoding.GetString (resp);
 736                 }
 737
 738                 public event DownloadDataCompletedEventHandler DownloadDataCompleted;
 739                 public event AsyncCompletedEventHandler DownloadFileCompleted;
 740                 public event DownloadProgressChangedEventHandler DownloadProgressChanged;
 741                 public event DownloadStringCompletedEventHandler DownloadStringCompleted;
 742                 public event OpenReadCompletedEventHandler OpenReadCompleted;
 743                 public event OpenWriteCompletedEventHandler OpenWriteCompleted;
 744                 public event UploadDataCompletedEventHandler UploadDataCompleted;
 745                 public event UploadFileCompletedEventHandler UploadFileCompleted;
 746                 public event UploadProgressChangedEventHandler UploadProgressChanged;
 747                 public event UploadStringCompletedEventHandler UploadStringCompleted;
 748                 public event UploadValuesCompletedEventHandler UploadValuesCompleted;
 749
 750                 Uri CreateUri (string address)
 751                 {
 752                         Uri uri;
 753                         try {
 754                                 if (baseAddress == null)
 755                                         uri = new Uri (address);
 756                                 else
 757                                         uri = new Uri (baseAddress, address);
 758                                 return CreateUri (uri);
 759                         } catch {
 760                         }
 761                         return new Uri (Path.GetFullPath (address));
 762                 }
 763
 764                 Uri CreateUri (Uri address)
 765                 {
 766                         Uri result = address;
 767                         if (baseAddress != null && !result.IsAbsoluteUri) {
 768                                 try {
 769                                         result = new Uri (baseAddress, result.OriginalString);
 770                                 } catch {
 771                                         return result; // Not much we can do here.
 772                                 }
 773                         }
 774
 775                         string query = result.Query;
 776                         if (String.IsNullOrEmpty (query))
 777                                 query = GetQueryString (true);
 778                         UriBuilder builder = new UriBuilder (address);
 779                         if (!String.IsNullOrEmpty (query))
 780                                 builder.Query = query.Substring (1);
 781                         return builder.Uri;
 782                 }
 783
 784                 string GetQueryString (bool add_qmark)
 785                 {
 786                         if (queryString == null || queryString.Count == 0)
 787                                 return null;
 788
 789                         StringBuilder sb = new StringBuilder ();
 790                         if (add_qmark)
 791                                 sb.Append ('?');
 792
 793                         foreach (string key in queryString)
 794                                 sb.AppendFormat ("{0}={1}&", key, UrlEncode (queryString [key]));
 795
 796                         if (sb.Length != 0)
 797                                 sb.Length--; // removes last '&' or the '?' if empty.
 798
 799                         if (sb.Length == 0)
 800                                 return null;
 801
 802                         return sb.ToString ();
 803                 }
 804
 805                 WebRequest SetupRequest (Uri uri)
 806                 {
 807                         WebRequest request = GetWebRequest (uri);
 808                         if (proxySet)
 809                                 request.Proxy = Proxy;
 810                         if (credentials != null)
 811                                 request.Credentials = credentials;
 812                         else if (!String.IsNullOrEmpty (uri.UserInfo)) {
 813                                 // Perhaps this should be done by the underlying URI handler?
 814                                 ICredentials creds = GetCredentials (uri.UserInfo);
 815                                 if (creds != null)
 816                                         request.Credentials = creds;
 817                         }
 818
 819                         // Special headers. These are properties of HttpWebRequest.
 820                         // What do we do with other requests differnt from HttpWebRequest?
 821                         if (headers != null && headers.Count != 0 && (request is HttpWebRequest)) {
 822                                 HttpWebRequest req = (HttpWebRequest) request;
 823                                 string expect = headers ["Expect"];
 824                                 string contentType = headers ["Content-Type"];
 825                                 string accept = headers ["Accept"];
 826                                 string connection = headers ["Connection"];
 827                                 string userAgent = headers ["User-Agent"];
 828                                 string referer = headers ["Referer"];
 829                                 headers.RemoveInternal ("Expect");
 830                                 headers.RemoveInternal ("Content-Type");
 831                                 headers.RemoveInternal ("Accept");
 832                                 headers.RemoveInternal ("Connection");
 833                                 headers.RemoveInternal ("Referer");
 834                                 headers.RemoveInternal ("User-Agent");
 835                                 request.Headers = headers;
 836
 837                                 if (expect != null && expect.Length > 0)
 838                                         req.Expect = expect;
 839
 840                                 if (accept != null && accept.Length > 0)
 841                                         req.Accept = accept;
 842
 843                                 if (contentType != null && contentType.Length > 0)
 844                                         req.ContentType = contentType;
 845
 846                                 if (connection != null && connection.Length > 0)
 847                                         req.Connection = connection;
 848
 849                                 if (userAgent != null && userAgent.Length > 0)
 850                                         req.UserAgent = userAgent;
 851
 852                                 if (referer != null && referer.Length > 0)
 853                                         req.Referer = referer;
 854                         }
 855
 856                         responseHeaders = null;
 857                         return request;
 858                 }
 859
 860                 WebRequest SetupRequest (Uri uri, string method, bool is_upload)
 861                 {
 862                         WebRequest request = SetupRequest (uri);
 863                         request.Method = DetermineMethod (uri, method, is_upload);
 864                         return request;
 865                 }
 866
 867                 static NetworkCredential GetCredentials (string user_info)
 868                 {
 869                         string [] creds = user_info.Split (':');
 870                         if (creds.Length != 2)
 871                                 return null;
 872
 873                         if (creds [0].IndexOf ('\\') != -1) {
 874                                 string [] user = creds [0].Split ('\\');
 875                                 if (user.Length != 2)
 876                                         return null;
 877                                 return new NetworkCredential (user [1], creds [1], user [0]);
 878                         }
 879                         return new NetworkCredential (creds [0], creds [1]);
 880                 }
 881
 882                 byte [] ReadAll (WebRequest request, object userToken)
 883                 {
 884                         WebResponse response = GetWebResponse (request);
 885                         Stream stream = response.GetResponseStream ();
 886                         int length = (int) response.ContentLength;
 887                         HttpWebRequest wreq = request as HttpWebRequest;
 888
 889                         if (length > -1 && wreq != null && (int) wreq.AutomaticDecompression != 0) {
 890                                 string content_encoding = ((HttpWebResponse) response).ContentEncoding;
 891                                 if (((content_encoding == "gzip" && (wreq.AutomaticDecompression & DecompressionMethods.GZip) != 0)) ||
 892                                         ((content_encoding == "deflate" && (wreq.AutomaticDecompression & DecompressionMethods.Deflate) != 0)))
 893                                         length = -1;
 894                         }
 895
 896                         MemoryStream ms = null;
 897                         bool nolength = (length == -1);
 898                         int size = ((nolength) ? 8192 : length);
 899                         if (nolength)
 900                                 ms = new MemoryStream ();
 901
 902                         long total = 0;
 903                         int nread = 0;
 904                         int offset = 0;
 905                         byte [] buffer = new byte [size];
 906                         while ((nread = stream.Read (buffer, offset, size)) != 0) {
 907                                 if (nolength) {
 908                                         ms.Write (buffer, 0, nread);
 909                                 } else {
 910                                         offset += nread;
 911                                         size -= nread;
 912                                 }
 913                                 if (async){
 914                                         total += nread;
 915                                         OnDownloadProgressChanged (new DownloadProgressChangedEventArgs (total, length, userToken));
 916                                 }
 917                         }
 918
 919                         if (nolength)
 920                                 return ms.ToArray ();
 921
 922                         return buffer;
 923                 }
 924
 925                 string UrlEncode (string str)
 926                 {
 927                         StringBuilder result = new StringBuilder ();
 928
 929                         int len = str.Length;
 930                         for (int i = 0; i < len; i++) {
 931                                 char c = str [i];
 932                                 if (c == ' ')
 933                                         result.Append ('+');
 934                                 else if ((c < '0' && c != '-' && c != '.') ||
 935                                          (c < 'A' && c > '9') ||
 936                                          (c > 'Z' && c < 'a' && c != '_') ||
 937                                          (c > 'z')) {
 938                                         result.Append ('%');
 939                                         int idx = ((int) c) >> 4;
 940                                         result.Append ((char) hexBytes [idx]);
 941                                         idx = ((int) c) & 0x0F;
 942                                         result.Append ((char) hexBytes [idx]);
 943                                 } else {
 944                                         result.Append (c);
 945                                 }
 946                         }
 947
 948                         return result.ToString ();
 949                 }
 950
 951                 static void UrlEncodeAndWrite (Stream stream, byte [] bytes)
 952                 {
 953                         if (bytes == null)
 954                                 return;
 955
 956                         int len = bytes.Length;
 957                         if (len == 0)
 958                                 return;
 959
 960                         for (int i = 0; i < len; i++) {
 961                                 char c = (char) bytes [i];
 962                                 if (c == ' ')
 963                                         stream.WriteByte ((byte) '+');
 964                                 else if ((c < '0' && c != '-' && c != '.') ||
 965                                          (c < 'A' && c > '9') ||
 966                                          (c > 'Z' && c < 'a' && c != '_') ||
 967                                          (c > 'z')) {
 968                                         stream.WriteByte ((byte) '%');
 969                                         int idx = ((int) c) >> 4;
 970                                         stream.WriteByte (hexBytes [idx]);
 971                                         idx = ((int) c) & 0x0F;
 972                                         stream.WriteByte (hexBytes [idx]);
 973                                 } else {
 974                                         stream.WriteByte ((byte) c);
 975                                 }
 976                         }
 977                 }
 978
 979                 public void CancelAsync ()
 980                 {
 981                         lock (this){
 982                                 if (async_thread == null)
 983                                         return;
 984
 985                                 //
 986                                 // We first flag things as done, in case the Interrupt hangs
 987                                 // or the thread decides to hang in some other way inside the
 988                                 // event handlers, or if we are stuck somewhere else.  This
 989                                 // ensures that the WebClient object is reusable immediately
 990                                 //
 991                                 Thread t = async_thread;
 992                                 CompleteAsync ();
 993                                 t.Interrupt ();
 994                         }
 995                 }
 996
 997                 void CompleteAsync ()
 998                 {
 999                         lock (this){
1000                                 is_busy = false;
1001                                 async_thread = null;
1002                         }
1003                 }
1004
1005                 //    DownloadDataAsync
1006
1007                 public void DownloadDataAsync (Uri address)
1008                 {
1009                         DownloadDataAsync (address, null);
1010                 }
1011
1012                 public void DownloadDataAsync (Uri address, object userToken)
1013                 {
1014                         if (address == null)
1015                                 throw new ArgumentNullException ("address");
1016
1017                         lock (this) {
1018                                 SetBusy ();
1019                                 async = true;
1020
1021                                 async_thread = new Thread (delegate (object state) {
1022                                         object [] args = (object []) state;
1023                                         try {
1024                                                 byte [] data = DownloadDataCore ((Uri) args [0], args [1]);
1025                                                 OnDownloadDataCompleted (
1026                                                         new DownloadDataCompletedEventArgs (data, null, false, args [1]));
1027                                         } catch (ThreadInterruptedException){
1028                                                 OnDownloadDataCompleted (
1029                                                         new DownloadDataCompletedEventArgs (null, null, true, args [1]));
1030                                                 throw;
1031                                         } catch (Exception e){
1032                                                 OnDownloadDataCompleted (
1033                                                         new DownloadDataCompletedEventArgs (null, e, false, args [1]));
1034                                         }
1035                                 });
1036                                 object [] cb_args = new object [] {address, userToken};
1037                                 async_thread.Start (cb_args);
1038                         }
1039                 }
1040
1041                 //    DownloadFileAsync
1042
1043                 public void DownloadFileAsync (Uri address, string fileName)
1044                 {
1045                         DownloadFileAsync (address, fileName, null);
1046                 }
1047
1048                 public void DownloadFileAsync (Uri address, string fileName, object userToken)
1049                 {
1050                         if (address == null)
1051                                 throw new ArgumentNullException ("address");
1052                         if (fileName == null)
1053                                 throw new ArgumentNullException ("fileName");
1054
1055                         lock (this) {
1056                                 SetBusy ();
1057                                 async = true;
1058
1059                                 async_thread = new Thread (delegate (object state) {
1060                                         object [] args = (object []) state;
1061                                         try {
1062                                                 DownloadFileCore ((Uri) args [0], (string) args [1], args [2]);
1063                                                 OnDownloadFileCompleted (
1064                                                         new AsyncCompletedEventArgs (null, false, args [2]));
1065                                         } catch (ThreadInterruptedException){
1066                                                 OnDownloadFileCompleted (
1067                                                         new AsyncCompletedEventArgs (null, true, args [2]));
1068                                         } catch (Exception e){
1069                                                 OnDownloadFileCompleted (
1070                                                         new AsyncCompletedEventArgs (e, false, args [2]));
1071                                         }});
1072                                 object [] cb_args = new object [] {address, fileName, userToken};
1073                                 async_thread.Start (cb_args);
1074                         }
1075                 }
1076
1077                 //    DownloadStringAsync
1078
1079                 public void DownloadStringAsync (Uri address)
1080                 {
1081                         DownloadStringAsync (address, null);
1082                 }
1083
1084                 public void DownloadStringAsync (Uri address, object userToken)
1085                 {
1086                         if (address == null)
1087                                 throw new ArgumentNullException ("address");
1088
1089                         lock (this) {
1090                                 SetBusy ();
1091                                 async = true;
1092
1093                                 async_thread = new Thread (delegate (object state) {
1094                                         object [] args = (object []) state;
1095                                         try {
1096                                                 string data = encoding.GetString (DownloadDataCore ((Uri) args [0], args [1]));
1097                                                 OnDownloadStringCompleted (
1098                                                         new DownloadStringCompletedEventArgs (data, null, false, args [1]));
1099                                         } catch (ThreadInterruptedException){
1100                                                 OnDownloadStringCompleted (
1101                                                         new DownloadStringCompletedEventArgs (null, null, true, args [1]));
1102                                         } catch (Exception e){
1103                                                 OnDownloadStringCompleted (
1104                                                         new DownloadStringCompletedEventArgs (null, e, false, args [1]));
1105                                         }});
1106                                 object [] cb_args = new object [] {address, userToken};
1107                                 async_thread.Start (cb_args);
1108                         }
1109                 }
1110
1111                 //    OpenReadAsync
1112
1113                 public void OpenReadAsync (Uri address)
1114                 {
1115                         OpenReadAsync (address, null);
1116                 }
1117
1118                 public void OpenReadAsync (Uri address, object userToken)
1119                 {
1120                         if (address == null)
1121                                 throw new ArgumentNullException ("address");
1122
1123                         lock (this) {
1124                                 SetBusy ();
1125                                 async = true;
1126
1127                                 async_thread = new Thread (delegate (object state) {
1128                                         object [] args = (object []) state;
1129                                         WebRequest request = null;
1130                                         try {
1131                                                 request = SetupRequest ((Uri) args [0]);
1132                                                 WebResponse response = GetWebResponse (request);
1133                                                 Stream stream = response.GetResponseStream ();
1134                                                 OnOpenReadCompleted (
1135                                                         new OpenReadCompletedEventArgs (stream, null, false, args [1]));
1136                                         } catch (ThreadInterruptedException){
1137                                                 if (request != null)
1138                                                         request.Abort ();
1139
1140                                                 OnOpenReadCompleted (new OpenReadCompletedEventArgs (null, null, true, args [1]));
1141                                         } catch (Exception e){
1142                                                 OnOpenReadCompleted (new OpenReadCompletedEventArgs (null, e, false, args [1]));
1143                                         } });
1144                                 object [] cb_args = new object [] {address, userToken};
1145                                 async_thread.Start (cb_args);
1146                         }
1147                 }
1148
1149                 //    OpenWriteAsync
1150
1151                 public void OpenWriteAsync (Uri address)
1152                 {
1153                         OpenWriteAsync (address, null);
1154                 }
1155
1156                 public void OpenWriteAsync (Uri address, string method)
1157                 {
1158                         OpenWriteAsync (address, method, null);
1159                 }
1160
1161                 public void OpenWriteAsync (Uri address, string method, object userToken)
1162                 {
1163                         if (address == null)
1164                                 throw new ArgumentNullException ("address");
1165
1166                         lock (this) {
1167                                 SetBusy ();
1168                                 async = true;
1169
1170                                 async_thread = new Thread (delegate (object state) {
1171                                         object [] args = (object []) state;
1172                                         WebRequest request = null;
1173                                         try {
1174                                                 request = SetupRequest ((Uri) args [0], (string) args [1], true);
1175                                                 Stream stream = request.GetRequestStream ();
1176                                                 OnOpenWriteCompleted (
1177                                                         new OpenWriteCompletedEventArgs (stream, null, false, args [2]));
1178                                         } catch (ThreadInterruptedException){
1179                                                 if (request != null)
1180                                                         request.Abort ();
1181                                                 OnOpenWriteCompleted (
1182                                                         new OpenWriteCompletedEventArgs (null, null, true, args [2]));
1183                                         } catch (Exception e){
1184                                                 OnOpenWriteCompleted (
1185                                                         new OpenWriteCompletedEventArgs (null, e, false, args [2]));
1186                                         }});
1187                                 object [] cb_args = new object [] {address, method, userToken};
1188                                 async_thread.Start (cb_args);
1189                         }
1190                 }
1191
1192                 //    UploadDataAsync
1193
1194                 public void UploadDataAsync (Uri address, byte [] data)
1195                 {
1196                         UploadDataAsync (address, null, data);
1197                 }
1198
1199                 public void UploadDataAsync (Uri address, string method, byte [] data)
1200                 {
1201                         UploadDataAsync (address, method, data, null);
1202                 }
1203
1204                 public void UploadDataAsync (Uri address, string method, byte [] data, object userToken)
1205                 {
1206                         if (address == null)
1207                                 throw new ArgumentNullException ("address");
1208                         if (data == null)
1209                                 throw new ArgumentNullException ("data");
1210
1211                         lock (this) {
1212                                 SetBusy ();
1213                                 async = true;
1214
1215                                 async_thread = new Thread (delegate (object state) {
1216                                         object [] args = (object []) state;
1217                                         byte [] data2;
1218
1219                                         try {
1220                                                 data2 = UploadDataCore ((Uri) args [0], (string) args [1], (byte []) args [2], args [3]);
1221
1222                                                 OnUploadDataCompleted (
1223                                                         new UploadDataCompletedEventArgs (data2, null, false, args [3]));
1224                                         } catch (ThreadInterruptedException){
1225                                                 OnUploadDataCompleted (
1226                                                         new UploadDataCompletedEventArgs (null, null, true, args [3]));
1227                                         } catch (Exception e){
1228                                                 OnUploadDataCompleted (
1229                                                         new UploadDataCompletedEventArgs (null, e, false, args [3]));
1230                                         }});
1231                                 object [] cb_args = new object [] {address, method, data,  userToken};
1232                                 async_thread.Start (cb_args);
1233                         }
1234                 }
1235
1236                 //    UploadFileAsync
1237
1238                 public void UploadFileAsync (Uri address, string fileName)
1239                 {
1240                         UploadFileAsync (address, null, fileName);
1241                 }
1242
1243                 public void UploadFileAsync (Uri address, string method, string fileName)
1244                 {
1245                         UploadFileAsync (address, method, fileName, null);
1246                 }
1247
1248                 public void UploadFileAsync (Uri address, string method, string fileName, object userToken)
1249                 {
1250                         if (address == null)
1251                                 throw new ArgumentNullException ("address");
1252                         if (fileName == null)
1253                                 throw new ArgumentNullException ("fileName");
1254
1255                         lock (this) {
1256                                 SetBusy ();
1257                                 async = true;
1258
1259                                 async_thread = new Thread (delegate (object state) {
1260                                         object [] args = (object []) state;
1261                                         byte [] data;
1262
1263                                         try {
1264                                                 data = UploadFileCore ((Uri) args [0], (string) args [1], (string) args [2], args [3]);
1265                                                 OnUploadFileCompleted (
1266                                                         new UploadFileCompletedEventArgs (data, null, false, args [3]));
1267                                         } catch (ThreadInterruptedException){
1268                                                 OnUploadFileCompleted (
1269                                                         new UploadFileCompletedEventArgs (null, null, true, args [3]));
1270                                         } catch (Exception e){
1271                                                 OnUploadFileCompleted (
1272                                                         new UploadFileCompletedEventArgs (null, e, false, args [3]));
1273                                         }});
1274                                 object [] cb_args = new object [] {address, method, fileName,  userToken};
1275                                 async_thread.Start (cb_args);
1276                         }
1277                 }
1278
1279                 //    UploadStringAsync
1280
1281                 public void UploadStringAsync (Uri address, string data)
1282                 {
1283                         UploadStringAsync (address, null, data);
1284                 }
1285
1286                 public void UploadStringAsync (Uri address, string method, string data)
1287                 {
1288                         UploadStringAsync (address, method, data, null);
1289                 }
1290
1291                 public void UploadStringAsync (Uri address, string method, string data, object userToken)
1292                 {
1293                         if (address == null)
1294                                 throw new ArgumentNullException ("address");
1295                         if (data == null)
1296                                 throw new ArgumentNullException ("data");
1297
1298                         lock (this) {
1299                                 CheckBusy ();
1300                                 async = true;
1301
1302                                 async_thread = new Thread (delegate (object state) {
1303                                         object [] args = (object []) state;
1304
1305                                         try {
1306                                                 string data2 = UploadString ((Uri) args [0], (string) args [1], (string) args [2]);
1307                                                 OnUploadStringCompleted (
1308                                                         new UploadStringCompletedEventArgs (data2, null, false, args [3]));
1309                                         } catch (ThreadInterruptedException){
1310                                                 OnUploadStringCompleted (
1311                                                         new UploadStringCompletedEventArgs (null, null, true, args [3]));
1312                                         } catch (Exception e){
1313                                                 OnUploadStringCompleted (
1314                                                         new UploadStringCompletedEventArgs (null, e, false, args [3]));
1315                                         }});
1316                                 object [] cb_args = new object [] {address, method, data, userToken};
1317                                 async_thread.Start (cb_args);
1318                         }
1319                 }
1320
1321                 //    UploadValuesAsync
1322
1323                 public void UploadValuesAsync (Uri address, NameValueCollection data)
1324                 {
1325                         UploadValuesAsync (address, null, data);
1326                 }
1327
1328                 public void UploadValuesAsync (Uri address, string method, NameValueCollection data)
1329                 {
1330                         UploadValuesAsync (address, method, data, null);
1331                 }
1332
1333                 public void UploadValuesAsync (Uri address, string method, NameValueCollection data, object userToken)
1334                 {
1335                         if (address == null)
1336                                 throw new ArgumentNullException ("address");
1337                         if (data == null)
1338                                 throw new ArgumentNullException ("data");
1339
1340                         lock (this) {
1341                                 CheckBusy ();
1342                                 async = true;
1343
1344                                 async_thread = new Thread (delegate (object state) {
1345                                         object [] args = (object []) state;
1346                                         try {
1347                                                 byte [] values = UploadValuesCore ((Uri) args [0], (string) args [1], (NameValueCollection) args [2], args [3]);
1348                                                 OnUploadValuesCompleted (
1349                                                         new UploadValuesCompletedEventArgs (values, null, false, args [3]));
1350                                         } catch (ThreadInterruptedException){
1351                                                 OnUploadValuesCompleted (
1352                                                         new UploadValuesCompletedEventArgs (null, null, true, args [3]));
1353                                         } catch (Exception e){
1354                                                 OnUploadValuesCompleted (
1355                                                         new UploadValuesCompletedEventArgs (null, e, false, args [3]));
1356                                         }});
1357                                 object [] cb_args = new object [] {address, method, data,  userToken};
1358                                 async_thread.Start (cb_args);
1359                         }
1360                 }
1361
1362                 protected virtual void OnDownloadDataCompleted (DownloadDataCompletedEventArgs e)
1363                 {
1364                         CompleteAsync ();
1365                         if (DownloadDataCompleted != null)
1366                                 DownloadDataCompleted (this, e);
1367                 }
1368
1369                 protected virtual void OnDownloadFileCompleted (AsyncCompletedEventArgs e)
1370                 {
1371                         CompleteAsync ();
1372                         if (DownloadFileCompleted != null)
1373                                 DownloadFileCompleted (this, e);
1374                 }
1375
1376                 protected virtual void OnDownloadProgressChanged (DownloadProgressChangedEventArgs e)
1377                 {
1378                         if (DownloadProgressChanged != null)
1379                                 DownloadProgressChanged (this, e);
1380                 }
1381
1382                 protected virtual void OnDownloadStringCompleted (DownloadStringCompletedEventArgs e)
1383                 {
1384                         CompleteAsync ();
1385                         if (DownloadStringCompleted != null)
1386                                 DownloadStringCompleted (this, e);
1387                 }
1388
1389                 protected virtual void OnOpenReadCompleted (OpenReadCompletedEventArgs e)
1390                 {
1391                         CompleteAsync ();
1392                         if (OpenReadCompleted != null)
1393                                 OpenReadCompleted (this, e);
1394                 }
1395
1396                 protected virtual void OnOpenWriteCompleted (OpenWriteCompletedEventArgs e)
1397                 {
1398                         CompleteAsync ();
1399                         if (OpenWriteCompleted != null)
1400                                 OpenWriteCompleted (this, e);
1401                 }
1402
1403                 protected virtual void OnUploadDataCompleted (UploadDataCompletedEventArgs e)
1404                 {
1405                         CompleteAsync ();
1406                         if (UploadDataCompleted != null)
1407                                 UploadDataCompleted (this, e);
1408                 }
1409
1410                 protected virtual void OnUploadFileCompleted (UploadFileCompletedEventArgs e)
1411                 {
1412                         CompleteAsync ();
1413                         if (UploadFileCompleted != null)
1414                                 UploadFileCompleted (this, e);
1415                 }
1416
1417                 protected virtual void OnUploadProgressChanged (UploadProgressChangedEventArgs e)
1418                 {
1419                         if (UploadProgressChanged != null)
1420                                 UploadProgressChanged (this, e);
1421                 }
1422
1423                 protected virtual void OnUploadStringCompleted (UploadStringCompletedEventArgs e)
1424                 {
1425                         CompleteAsync ();
1426                         if (UploadStringCompleted != null)
1427                                 UploadStringCompleted (this, e);
1428                 }
1429
1430                 protected virtual void OnUploadValuesCompleted (UploadValuesCompletedEventArgs e)
1431                 {
1432                         CompleteAsync ();
1433                         if (UploadValuesCompleted != null)
1434                                 UploadValuesCompleted (this, e);
1435                 }
1436
1437                 protected virtual WebResponse GetWebResponse (WebRequest request, IAsyncResult result)
1438                 {
1439                         WebResponse response = request.EndGetResponse (result);
1440                         responseHeaders = response.Headers;
1441                         return response;
1442                 }
1443
1444                 protected virtual WebRequest GetWebRequest (Uri address)
1445                 {
1446                         return WebRequest.Create (address);
1447                 }
1448
1449                 protected virtual WebResponse GetWebResponse (WebRequest request)
1450                 {
1451                         WebResponse response = request.GetResponse ();
1452                         responseHeaders = response.Headers;
1453                         return response;
1454                 }
1455
1456         }
1457 }
1458