mcs/class/System/System.Net/FtpWebRequest.cs

   1 //
   2 // System.Net.FtpWebRequest.cs
   3 //
   4 // Authors:
   5 //      Carlos Alberto Cortez (calberto.cortez@gmail.com)
   6 //
   7 // (c) Copyright 2006 Novell, Inc. (http://www.novell.com)
   8 //
   9 #if NET_2_0
  10
  11 using System;
  12 using System.IO;
  13 using System.Net.Sockets;
  14 using System.Text;
  15 using System.Threading;
  16 using System.Net.Cache;
  17 using System.Security.Cryptography.X509Certificates;
  18 using System.Net;
  19
  20
  21 namespace System.Net
  22 {
  23         public sealed class FtpWebRequest : WebRequest
  24         {
  25                 Uri requestUri;
  26                 string file_name; // By now, used for upload
  27                 ServicePoint servicePoint;
  28                 Socket dataSocket;
  29                 NetworkStream controlStream;
  30                 StreamReader controlReader;
  31                 NetworkCredential credentials;
  32                 IPHostEntry hostEntry;
  33                 IPEndPoint localEndPoint;
  34                 IWebProxy proxy;
  35                 int timeout = 100000;
  36                 int rwTimeout = 300000;
  37                 long offset = 0;
  38                 bool binary = true;
  39                 bool enableSsl = false;
  40                 bool usePassive = true;
  41                 bool keepAlive = false;
  42                 string method = WebRequestMethods.Ftp.DownloadFile;
  43                 string renameTo;
  44                 object locker = new object ();
  45
  46                 RequestState requestState = RequestState.Before;
  47                 FtpAsyncResult asyncResult;
  48                 FtpWebResponse ftpResponse;
  49                 Stream requestStream;
  50                 string initial_path;
  51
  52                 const string ChangeDir = "CWD";
  53                 const string UserCommand = "USER";
  54                 const string PasswordCommand = "PASS";
  55                 const string TypeCommand = "TYPE";
  56                 const string PassiveCommand = "PASV";
  57                 const string PortCommand = "PORT";
  58                 const string AbortCommand = "ABOR";
  59                 const string AuthCommand = "AUTH";
  60                 const string RestCommand = "REST";
  61                 const string RenameFromCommand = "RNFR";
  62                 const string RenameToCommand = "RNTO";
  63                 const string QuitCommand = "QUIT";
  64                 const string EOL = "\r\n"; // Special end of line
  65
  66                 enum RequestState
  67                 {
  68                         Before,
  69                         Scheduled,
  70                         Connecting,
  71                         Authenticating,
  72                         OpeningData,
  73                         TransferInProgress,
  74                         Finished,
  75                         Aborted,
  76                         Error
  77                 }
  78
  79                 // sorted commands
  80                 static readonly string [] supportedCommands = new string [] {
  81                         WebRequestMethods.Ftp.AppendFile, // APPE
  82                         WebRequestMethods.Ftp.DeleteFile, // DELE
  83                         WebRequestMethods.Ftp.ListDirectoryDetails, // LIST
  84                         WebRequestMethods.Ftp.GetDateTimestamp, // MDTM
  85                         WebRequestMethods.Ftp.MakeDirectory, // MKD
  86                         WebRequestMethods.Ftp.ListDirectory, // NLST
  87                         WebRequestMethods.Ftp.PrintWorkingDirectory, // PWD
  88                         WebRequestMethods.Ftp.Rename, // RENAME
  89                         WebRequestMethods.Ftp.DownloadFile, // RETR
  90                         WebRequestMethods.Ftp.RemoveDirectory, // RMD
  91                         WebRequestMethods.Ftp.GetFileSize, // SIZE
  92                         WebRequestMethods.Ftp.UploadFile, // STOR
  93                         WebRequestMethods.Ftp.UploadFileWithUniqueName // STUR
  94                         };
  95
  96                 internal FtpWebRequest (Uri uri)
  97                 {
  98                         this.requestUri = uri;
  99                         this.proxy = GlobalProxySelection.Select;
 100                 }
 101
 102                 static Exception GetMustImplement ()
 103                 {
 104                         return new NotImplementedException ();
 105                 }
 106
 107                 [MonoTODO]
 108                 public X509CertificateCollection ClientCertificates
 109                 {
 110                         get {
 111                                 throw GetMustImplement ();
 112                         }
 113                         set {
 114                                 throw GetMustImplement ();
 115                         }
 116                 }
 117
 118                 [MonoTODO]
 119                 public override string ConnectionGroupName
 120                 {
 121                         get {
 122                                 throw GetMustImplement ();
 123                         }
 124                         set {
 125                                 throw GetMustImplement ();
 126                         }
 127                 }
 128
 129                 public override string ContentType {
 130                         get {
 131                                 throw new NotSupportedException ();
 132                         }
 133                         set {
 134                                 throw new NotSupportedException ();
 135                         }
 136                 }
 137
 138                 public override long ContentLength {
 139                         get {
 140                                 return 0;
 141                         }
 142                         set {
 143                                 // DO nothing
 144                         }
 145                 }
 146
 147                 public long ContentOffset {
 148                         get {
 149                                 return offset;
 150                         }
 151                         set {
 152                                 CheckRequestStarted ();
 153                                 if (value < 0)
 154                                         throw new ArgumentOutOfRangeException ();
 155
 156                                 offset = value;
 157                         }
 158                 }
 159
 160                 public override ICredentials Credentials {
 161                         get {
 162                                 return credentials;
 163                         }
 164                         set {
 165                                 CheckRequestStarted ();
 166                                 if (value == null)
 167                                         throw new ArgumentNullException ();
 168                                 if (!(value is NetworkCredential))
 169                                         throw new ArgumentException ();
 170
 171                                 credentials = value as NetworkCredential;
 172                         }
 173                 }
 174
 175                 [MonoTODO]
 176                 public static new RequestCachePolicy DefaultCachePolicy
 177                 {
 178                         get {
 179                                 throw GetMustImplement ();
 180                         }
 181                         set {
 182                                 throw GetMustImplement ();
 183                         }
 184                 }
 185
 186                 public bool EnableSsl {
 187                         get {
 188                                 return enableSsl;
 189                         }
 190                         set {
 191                                 CheckRequestStarted ();
 192                                 enableSsl = value;
 193                         }
 194                 }
 195
 196                 [MonoTODO]
 197                 public override WebHeaderCollection Headers
 198                 {
 199                         get {
 200                                 throw GetMustImplement ();
 201                         }
 202                         set {
 203                                 throw GetMustImplement ();
 204                         }
 205                 }
 206
 207                 [MonoTODO ("We don't support KeepAlive = true")]
 208                 public bool KeepAlive {
 209                         get {
 210                                 return keepAlive;
 211                         }
 212                         set {
 213                                 CheckRequestStarted ();
 214                                 //keepAlive = value;
 215                         }
 216                 }
 217
 218                 public override string Method {
 219                         get {
 220                                 return method;
 221                         }
 222                         set {
 223                                 CheckRequestStarted ();
 224                                 if (value == null)
 225                                         throw new ArgumentNullException ("Method string cannot be null");
 226
 227                                 if (value.Length == 0 || Array.BinarySearch (supportedCommands, value) < 0)
 228                                         throw new ArgumentException ("Method not supported", "value");
 229
 230                                 method = value;
 231                         }
 232                 }
 233
 234                 public override bool PreAuthenticate {
 235                         get {
 236                                 throw new NotSupportedException ();
 237                         }
 238                         set {
 239                                 throw new NotSupportedException ();
 240                         }
 241                 }
 242
 243                 public override IWebProxy Proxy {
 244                         get {
 245                                 return proxy;
 246                         }
 247                         set {
 248                                 CheckRequestStarted ();
 249                                 if (value == null)
 250                                         throw new ArgumentNullException ();
 251
 252                                 proxy = value;
 253                         }
 254                 }
 255
 256                 public int ReadWriteTimeout {
 257                         get {
 258                                 return rwTimeout;
 259                         }
 260                         set {
 261                                 CheckRequestStarted ();
 262
 263                                 if (value < - 1)
 264                                         throw new ArgumentOutOfRangeException ();
 265                                 else
 266                                         rwTimeout = value;
 267                         }
 268                 }
 269
 270                 public string RenameTo {
 271                         get {
 272                                 return renameTo;
 273                         }
 274                         set {
 275                                 CheckRequestStarted ();
 276                                 if (value == null || value.Length == 0)
 277                                         throw new ArgumentException ("RenameTo value can't be null or empty", "RenameTo");
 278
 279                                 renameTo = value;
 280                         }
 281                 }
 282
 283                 public override Uri RequestUri {
 284                         get {
 285                                 return requestUri;
 286                         }
 287                 }
 288
 289                 public ServicePoint ServicePoint {
 290                         get {
 291                                 return GetServicePoint ();
 292                         }
 293                 }
 294
 295                 public bool UsePassive {
 296                         get {
 297                                 return usePassive;
 298                         }
 299                         set {
 300                                 CheckRequestStarted ();
 301                                 usePassive = value;
 302                         }
 303                 }
 304
 305                 [MonoTODO]
 306                 public override bool UseDefaultCredentials
 307                 {
 308                         get {
 309                                 throw GetMustImplement ();
 310                         }
 311                         set {
 312                                 throw GetMustImplement ();
 313                         }
 314                 }
 315
 316                 public bool UseBinary {
 317                         get {
 318                                 return binary;
 319                         } set {
 320                                 CheckRequestStarted ();
 321                                 binary = value;
 322                         }
 323                 }
 324
 325                 public override int Timeout {
 326                         get {
 327                                 return timeout;
 328                         }
 329                         set {
 330                                 CheckRequestStarted ();
 331
 332                                 if (value < -1)
 333                                         throw new ArgumentOutOfRangeException ();
 334                                 else
 335                                         timeout = value;
 336                         }
 337                 }
 338
 339                 string DataType {
 340                         get {
 341                                 return binary ? "I" : "A";
 342                         }
 343                 }
 344
 345                 RequestState State {
 346                         get {
 347                                 lock (locker) {
 348                                         return requestState;
 349                                 }
 350                         }
 351
 352                         set {
 353                                 lock (locker) {
 354                                         CheckIfAborted ();
 355                                         CheckFinalState ();
 356                                         requestState = value;
 357                                 }
 358                         }
 359                 }
 360
 361                 public override void Abort () {
 362                         lock (locker) {
 363                                 if (State == RequestState.TransferInProgress) {
 364                                         /*FtpStatus status = */
 365                                         SendCommand (false, AbortCommand);
 366                                 }
 367
 368                                 if (!InFinalState ()) {
 369                                         State = RequestState.Aborted;
 370                                         ftpResponse = new FtpWebResponse (this, requestUri, method, FtpStatusCode.FileActionAborted, "Aborted by request");
 371                                 }
 372                         }
 373                 }
 374
 375                 public override IAsyncResult BeginGetResponse (AsyncCallback callback, object state) {
 376                         if (asyncResult != null && !asyncResult.IsCompleted) {
 377                                 throw new InvalidOperationException ("Cannot re-call BeginGetRequestStream/BeginGetResponse while a previous call is still in progress");
 378                         }
 379
 380                         CheckIfAborted ();
 381
 382                         asyncResult = new FtpAsyncResult (callback, state);
 383
 384                         lock (locker) {
 385                                 if (InFinalState ())
 386                                         asyncResult.SetCompleted (true, ftpResponse);
 387                                 else {
 388                                         if (State == RequestState.Before)
 389                                                 State = RequestState.Scheduled;
 390
 391                                         Thread thread = new Thread (ProcessRequest);
 392                                         thread.Start ();
 393                                 }
 394                         }
 395
 396                         return asyncResult;
 397                 }
 398
 399                 public override WebResponse EndGetResponse (IAsyncResult asyncResult) {
 400                         if (asyncResult == null)
 401                                 throw new ArgumentNullException ("AsyncResult cannot be null!");
 402
 403                         if (!(asyncResult is FtpAsyncResult) || asyncResult != this.asyncResult)
 404                                 throw new ArgumentException ("AsyncResult is from another request!");
 405
 406                         FtpAsyncResult asyncFtpResult = (FtpAsyncResult) asyncResult;
 407                         if (!asyncFtpResult.WaitUntilComplete (timeout, false)) {
 408                                 Abort ();
 409                                 throw new WebException ("Transfer timed out.", WebExceptionStatus.Timeout);
 410                         }
 411
 412                         CheckIfAborted ();
 413
 414                         asyncResult = null;
 415
 416                         if (asyncFtpResult.GotException)
 417                                 throw asyncFtpResult.Exception;
 418
 419                         return asyncFtpResult.Response;
 420                 }
 421
 422                 public override WebResponse GetResponse () {
 423                         IAsyncResult asyncResult = BeginGetResponse (null, null);
 424                         return EndGetResponse (asyncResult);
 425                 }
 426
 427                 public override IAsyncResult BeginGetRequestStream (AsyncCallback callback, object state) {
 428                         if (method != WebRequestMethods.Ftp.UploadFile && method != WebRequestMethods.Ftp.UploadFileWithUniqueName &&
 429                                         method != WebRequestMethods.Ftp.AppendFile)
 430                                 throw new ProtocolViolationException ();
 431
 432                         lock (locker) {
 433                                 CheckIfAborted ();
 434
 435                                 if (State != RequestState.Before)
 436                                         throw new InvalidOperationException ("Cannot re-call BeginGetRequestStream/BeginGetResponse while a previous call is still in progress");
 437
 438                                 State = RequestState.Scheduled;
 439                         }
 440
 441                         asyncResult = new FtpAsyncResult (callback, state);
 442                         Thread thread = new Thread (ProcessRequest);
 443                         thread.Start ();
 444
 445                         return asyncResult;
 446                 }
 447
 448                 public override Stream EndGetRequestStream (IAsyncResult asyncResult) {
 449                         if (asyncResult == null)
 450                                 throw new ArgumentNullException ("asyncResult");
 451
 452                         if (!(asyncResult is FtpAsyncResult))
 453                                 throw new ArgumentException ("asyncResult");
 454
 455                         if (State == RequestState.Aborted) {
 456                                 throw new WebException ("Request aborted", WebExceptionStatus.RequestCanceled);
 457                         }
 458
 459                         if (asyncResult != this.asyncResult)
 460                                 throw new ArgumentException ("AsyncResult is from another request!");
 461
 462                         FtpAsyncResult res = (FtpAsyncResult) asyncResult;
 463
 464                         if (!res.WaitUntilComplete (timeout, false)) {
 465                                 Abort ();
 466                                 throw new WebException ("Request timed out");
 467                         }
 468
 469                         if (res.GotException)
 470                                 throw res.Exception;
 471
 472                         return res.Stream;
 473                 }
 474
 475                 public override Stream GetRequestStream () {
 476                         IAsyncResult asyncResult = BeginGetRequestStream (null, null);
 477                         return EndGetRequestStream (asyncResult);
 478                 }
 479
 480                 ServicePoint GetServicePoint ()
 481                 {
 482                         if (servicePoint == null)
 483                                 servicePoint = ServicePointManager.FindServicePoint (requestUri, proxy);
 484
 485                         return servicePoint;
 486                 }
 487
 488                 // Probably move some code of command connection here
 489                 void ResolveHost ()
 490                 {
 491                         CheckIfAborted ();
 492                         hostEntry = GetServicePoint ().HostEntry;
 493
 494                         if (hostEntry == null) {
 495                                 ftpResponse.UpdateStatus (new FtpStatus(FtpStatusCode.ActionAbortedLocalProcessingError, "Cannot resolve server name"));
 496                                 throw new WebException ("The remote server name could not be resolved: " + requestUri,
 497                                         null, WebExceptionStatus.NameResolutionFailure, ftpResponse);
 498                         }
 499                 }
 500
 501                 void ProcessRequest () {
 502
 503                         if (State == RequestState.Scheduled) {
 504                                 ftpResponse = new FtpWebResponse (this, requestUri, method, keepAlive);
 505
 506                                 try {
 507                                         ProcessMethod ();
 508                                         //State = RequestState.Finished;
 509                                         //finalResponse = ftpResponse;
 510                                         asyncResult.SetCompleted (false, ftpResponse);
 511                                 }
 512                                 catch (Exception e) {
 513                                         State = RequestState.Error;
 514                                         SetCompleteWithError (e);
 515                                 }
 516                         }
 517                         else {
 518                                 if (InProgress ()) {
 519                                         FtpStatus status = GetResponseStatus ();
 520
 521                                         ftpResponse.UpdateStatus (status);
 522
 523                                         if (ftpResponse.IsFinal ()) {
 524                                                 State = RequestState.Finished;
 525                                         }
 526                                 }
 527
 528                                 asyncResult.SetCompleted (false, ftpResponse);
 529                         }
 530                 }
 531
 532                 void SetType ()
 533                 {
 534                         if (binary) {
 535                                 FtpStatus status = SendCommand (TypeCommand, DataType);
 536                                 if ((int) status.StatusCode < 200 || (int) status.StatusCode >= 300)
 537                                         throw CreateExceptionFromResponse (status);
 538                         }
 539                 }
 540
 541                 string GetRemoteFolderPath (Uri uri)
 542                 {
 543                         string result;
 544                         string local_path = Uri.UnescapeDataString (uri.LocalPath);
 545                         if (initial_path == null || initial_path == "/") {
 546                                 result = local_path;
 547                         } else {
 548                                 if (local_path [0] == '/')
 549                                         local_path = local_path.Substring (1);
 550
 551                                 Uri initial = new Uri ("ftp://dummy-host" + initial_path);
 552                                 result = new Uri (initial, local_path).LocalPath;
 553                         }
 554
 555                         int last = result.LastIndexOf ('/');
 556                         if (last == -1)
 557                                 return null;
 558
 559                         return result.Substring (0, last + 1);
 560                 }
 561
 562                 void CWDAndSetFileName (Uri uri)
 563                 {
 564                         string remote_folder = GetRemoteFolderPath (uri);
 565                         FtpStatus status;
 566                         if (remote_folder != null) {
 567                                 status = SendCommand (ChangeDir, remote_folder);
 568                                 if ((int) status.StatusCode < 200 || (int) status.StatusCode >= 300)
 569                                         throw CreateExceptionFromResponse (status);
 570
 571                                 int last = uri.LocalPath.LastIndexOf ('/');
 572                                 if (last >= 0) {
 573                                         file_name = Uri.UnescapeDataString (uri.LocalPath.Substring (last + 1));
 574                                 }
 575                         }
 576                 }
 577
 578                 void ProcessMethod ()
 579                 {
 580                         State = RequestState.Connecting;
 581
 582                         ResolveHost ();
 583
 584                         OpenControlConnection ();
 585                         CWDAndSetFileName (requestUri);
 586                         SetType ();
 587
 588                         switch (method) {
 589                         // Open data connection and receive data
 590                         case WebRequestMethods.Ftp.DownloadFile:
 591                         case WebRequestMethods.Ftp.ListDirectory:
 592                         case WebRequestMethods.Ftp.ListDirectoryDetails:
 593                                 DownloadData ();
 594                                 break;
 595                         // Open data connection and send data
 596                         case WebRequestMethods.Ftp.AppendFile:
 597                         case WebRequestMethods.Ftp.UploadFile:
 598                         case WebRequestMethods.Ftp.UploadFileWithUniqueName:
 599                                 UploadData ();
 600                                 break;
 601                         // Get info from control connection
 602                         case WebRequestMethods.Ftp.GetFileSize:
 603                         case WebRequestMethods.Ftp.GetDateTimestamp:
 604                         case WebRequestMethods.Ftp.PrintWorkingDirectory:
 605                         case WebRequestMethods.Ftp.MakeDirectory:
 606                         case WebRequestMethods.Ftp.Rename:
 607                         case WebRequestMethods.Ftp.DeleteFile:
 608                                 ProcessSimpleMethod ();
 609                                 break;
 610                         default: // What to do here?
 611                                 throw new Exception (String.Format ("Support for command {0} not implemented yet", method));
 612                         }
 613
 614                         CheckIfAborted ();
 615                 }
 616
 617                 private void CloseControlConnection () {
 618                         SendCommand (QuitCommand);
 619                         controlStream.Close ();
 620                 }
 621
 622                 private void CloseDataConnection () {
 623                         if(dataSocket != null)
 624                                 dataSocket.Close ();
 625                 }
 626
 627                 private void CloseConnection () {
 628                         CloseControlConnection ();
 629                         CloseDataConnection ();
 630                 }
 631
 632                 void ProcessSimpleMethod ()
 633                 {
 634                         State = RequestState.TransferInProgress;
 635
 636                         FtpStatus status;
 637
 638                         if (method == WebRequestMethods.Ftp.PrintWorkingDirectory)
 639                                 method = "PWD";
 640
 641                         if (method == WebRequestMethods.Ftp.Rename)
 642                                 method = RenameFromCommand;
 643
 644                         status = SendCommand (method, file_name);
 645
 646                         ftpResponse.Stream = Stream.Null;
 647
 648                         string desc = status.StatusDescription;
 649
 650                         switch (method) {
 651                         case WebRequestMethods.Ftp.GetFileSize: {
 652                                         if (status.StatusCode != FtpStatusCode.FileStatus)
 653                                                 throw CreateExceptionFromResponse (status);
 654
 655                                         int i, len;
 656                                         long size;
 657                                         for (i = 4, len = 0; i < desc.Length && Char.IsDigit (desc [i]); i++, len++)
 658                                                 ;
 659
 660                                         if (len == 0)
 661                                                 throw new WebException ("Bad format for server response in " + method);
 662
 663                                         if (!Int64.TryParse (desc.Substring (4, len), out size))
 664                                                 throw new WebException ("Bad format for server response in " + method);
 665
 666                                         ftpResponse.contentLength = size;
 667                                 }
 668                                 break;
 669                         case WebRequestMethods.Ftp.GetDateTimestamp:
 670                                 if (status.StatusCode != FtpStatusCode.FileStatus)
 671                                         throw CreateExceptionFromResponse (status);
 672                                 ftpResponse.LastModified = DateTime.ParseExact (desc.Substring (4), "yyyyMMddHHmmss", null);
 673                                 break;
 674                         case WebRequestMethods.Ftp.MakeDirectory:
 675                                 if (status.StatusCode != FtpStatusCode.PathnameCreated)
 676                                         throw CreateExceptionFromResponse (status);
 677                                 break;
 678                         case ChangeDir:
 679                                 method = WebRequestMethods.Ftp.PrintWorkingDirectory;
 680
 681                                 if (status.StatusCode != FtpStatusCode.FileActionOK)
 682                                         throw CreateExceptionFromResponse (status);
 683
 684                                 status = SendCommand (method);
 685
 686                                 if (status.StatusCode != FtpStatusCode.PathnameCreated)
 687                                         throw CreateExceptionFromResponse (status);
 688                                 break;
 689                         case RenameFromCommand:
 690                                 method = WebRequestMethods.Ftp.Rename;
 691                                 if (status.StatusCode != FtpStatusCode.FileCommandPending)
 692                                         throw CreateExceptionFromResponse (status);
 693                                 // Pass an empty string if RenameTo wasn't specified
 694                                 status = SendCommand (RenameToCommand, renameTo != null ? renameTo : String.Empty);
 695                                 if (status.StatusCode != FtpStatusCode.FileActionOK)
 696                                         throw CreateExceptionFromResponse (status);
 697                                 break;
 698                         case WebRequestMethods.Ftp.DeleteFile:
 699                                 if (status.StatusCode != FtpStatusCode.FileActionOK)  {
 700                                         throw CreateExceptionFromResponse (status);
 701                                 }
 702                                 break;
 703                         }
 704
 705                         State = RequestState.Finished;
 706                 }
 707
 708                 void UploadData ()
 709                 {
 710                         State = RequestState.OpeningData;
 711
 712                         OpenDataConnection ();
 713
 714                         State = RequestState.TransferInProgress;
 715                         requestStream = new FtpDataStream (this, dataSocket, false);
 716                         asyncResult.Stream = requestStream;
 717                 }
 718
 719                 void DownloadData ()
 720                 {
 721                         State = RequestState.OpeningData;
 722
 723                         OpenDataConnection ();
 724
 725                         State = RequestState.TransferInProgress;
 726                         ftpResponse.Stream = new FtpDataStream (this, dataSocket, true);
 727                 }
 728
 729                 void CheckRequestStarted ()
 730                 {
 731                         if (State != RequestState.Before)
 732                                 throw new InvalidOperationException ("There is a request currently in progress");
 733                 }
 734
 735                 void OpenControlConnection ()
 736                 {
 737                         Exception exception = null;
 738                         Socket sock = null;
 739                         foreach (IPAddress address in hostEntry.AddressList) {
 740                                 sock = new Socket (address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
 741
 742                                 IPEndPoint remote = new IPEndPoint (address, requestUri.Port);
 743
 744                                 if (!ServicePoint.CallEndPointDelegate (sock, remote)) {
 745                                         sock.Close ();
 746                                         sock = null;
 747                                 } else {
 748                                         try {
 749                                                 sock.Connect (remote);
 750                                                 localEndPoint = (IPEndPoint) sock.LocalEndPoint;
 751                                                 break;
 752                                         } catch (SocketException exc) {
 753                                                 exception = exc;
 754                                                 sock.Close ();
 755                                                 sock = null;
 756                                         }
 757                                 }
 758                         }
 759
 760                         // Couldn't connect to any address
 761                         if (sock == null)
 762                                 throw new WebException ("Unable to connect to remote server", exception,
 763                                                 WebExceptionStatus.UnknownError, ftpResponse);
 764
 765                         controlStream = new NetworkStream (sock);
 766                         controlReader = new StreamReader (controlStream, Encoding.ASCII);
 767
 768                         State = RequestState.Authenticating;
 769
 770                         Authenticate ();
 771                         FtpStatus status = SendCommand ("OPTS", "utf8", "on");
 772                         // ignore status for OPTS
 773                         status = SendCommand (WebRequestMethods.Ftp.PrintWorkingDirectory);
 774                         initial_path = GetInitialPath (status);
 775                 }
 776
 777                 static string GetInitialPath (FtpStatus status)
 778                 {
 779                         int s = (int) status.StatusCode;
 780                         if (s < 200 || s > 300 || status.StatusDescription.Length <= 4)
 781                                 throw new WebException ("Error getting current directory: " + status.StatusDescription, null,
 782                                                 WebExceptionStatus.UnknownError, null);
 783
 784                         string msg = status.StatusDescription.Substring (4);
 785                         if (msg [0] == '"') {
 786                                 int next_quote = msg.IndexOf ('\"', 1);
 787                                 if (next_quote == -1)
 788                                         throw new WebException ("Error getting current directory: PWD -> " + status.StatusDescription, null,
 789                                                                 WebExceptionStatus.UnknownError, null);
 790
 791                                 msg = msg.Substring (1, next_quote - 1);
 792                         }
 793
 794                         if (!msg.EndsWith ("/"))
 795                                 msg += "/";
 796                         return msg;
 797                 }
 798
 799                 // Probably we could do better having here a regex
 800                 Socket SetupPassiveConnection (string statusDescription)
 801                 {
 802                         // Current response string
 803                         string response = statusDescription;
 804                         if (response.Length < 4)
 805                                 throw new WebException ("Cannot open passive data connection");
 806
 807                         // Look for first digit after code
 808                         int i;
 809                         for (i = 3; i < response.Length && !Char.IsDigit (response [i]); i++)
 810                                 ;
 811                         if (i >= response.Length)
 812                                 throw new WebException ("Cannot open passive data connection");
 813
 814                         // Get six elements
 815                         string [] digits = response.Substring (i).Split (new char [] {','}, 6);
 816                         if (digits.Length != 6)
 817                                 throw new WebException ("Cannot open passive data connection");
 818
 819                         // Clean non-digits at the end of last element
 820                         int j;
 821                         for (j = digits [5].Length - 1; j >= 0 && !Char.IsDigit (digits [5][j]); j--)
 822                                 ;
 823                         if (j < 0)
 824                                 throw new WebException ("Cannot open passive data connection");
 825
 826                         digits [5] = digits [5].Substring (0, j + 1);
 827
 828                         IPAddress ip;
 829                         try {
 830                                 ip = IPAddress.Parse (String.Join (".", digits, 0, 4));
 831                         } catch (FormatException) {
 832                                 throw new WebException ("Cannot open passive data connection");
 833                         }
 834
 835                         // Get the port
 836                         int p1, p2, port;
 837                         if (!Int32.TryParse (digits [4], out p1) || !Int32.TryParse (digits [5], out p2))
 838                                 throw new WebException ("Cannot open passive data connection");
 839
 840                         port = (p1 << 8) + p2; // p1 * 256 + p2
 841                         //port = p1 * 256 + p2;
 842                         if (port < IPEndPoint.MinPort || port > IPEndPoint.MaxPort)
 843                                 throw new WebException ("Cannot open passive data connection");
 844
 845                         IPEndPoint ep = new IPEndPoint (ip, port);
 846                         Socket sock = new Socket (ep.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
 847                         try {
 848                                 sock.Connect (ep);
 849                         } catch (SocketException) {
 850                                 sock.Close ();
 851                                 throw new WebException ("Cannot open passive data connection");
 852                         }
 853
 854                         return sock;
 855                 }
 856
 857                 Exception CreateExceptionFromResponse (FtpStatus status)
 858                 {
 859                         FtpWebResponse ftpResponse = new FtpWebResponse (this, requestUri, method, status);
 860
 861                         WebException exc = new WebException ("Server returned an error: " + status.StatusDescription,
 862                                 null, WebExceptionStatus.ProtocolError, ftpResponse);
 863                         return exc;
 864                 }
 865
 866                 // Here we could also get a server error, so be cautious
 867                 internal void SetTransferCompleted ()
 868                 {
 869                         if (InFinalState ())
 870                                 return;
 871
 872                         State = RequestState.Finished;
 873                         FtpStatus status = GetResponseStatus ();
 874                         ftpResponse.UpdateStatus (status);
 875                         if(!keepAlive)
 876                                 CloseConnection ();
 877                 }
 878
 879                 internal void OperationCompleted ()
 880                 {
 881                         if(!keepAlive)
 882                                 CloseConnection ();
 883                 }
 884
 885                 void SetCompleteWithError (Exception exc)
 886                 {
 887                         if (asyncResult != null) {
 888                                 asyncResult.SetCompleted (false, exc);
 889                         }
 890                 }
 891
 892                 Socket InitDataConnection ()
 893                 {
 894                         FtpStatus status;
 895
 896                         if (usePassive) {
 897                                 status = SendCommand (PassiveCommand);
 898                                 if (status.StatusCode != FtpStatusCode.EnteringPassive) {
 899                                         throw CreateExceptionFromResponse (status);
 900                                 }
 901
 902                                 return SetupPassiveConnection (status.StatusDescription);
 903                         }
 904
 905                         // Open a socket to listen the server's connection
 906                         Socket sock = new Socket (AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
 907                         try {
 908                                 sock.Bind (new IPEndPoint (localEndPoint.Address, 0));
 909                                 sock.Listen (1); // We only expect a connection from server
 910
 911                         } catch (SocketException e) {
 912                                 sock.Close ();
 913
 914                                 throw new WebException ("Couldn't open listening socket on client", e);
 915                         }
 916
 917                         IPEndPoint ep = (IPEndPoint) sock.LocalEndPoint;
 918                         string ipString = ep.Address.ToString ().Replace ('.', ',');
 919                         int h1 = ep.Port >> 8; // ep.Port / 256
 920                         int h2 = ep.Port % 256;
 921
 922                         string portParam = ipString + "," + h1 + "," + h2;
 923                         status = SendCommand (PortCommand, portParam);
 924
 925                         if (status.StatusCode != FtpStatusCode.CommandOK) {
 926                                 sock.Close ();
 927                                 throw (CreateExceptionFromResponse (status));
 928                         }
 929
 930                         return sock;
 931                 }
 932
 933                 void OpenDataConnection ()
 934                 {
 935                         FtpStatus status;
 936
 937                         Socket s = InitDataConnection ();
 938
 939                         // Handle content offset
 940                         if (offset > 0) {
 941                                 status = SendCommand (RestCommand, offset.ToString ());
 942                                 if (status.StatusCode != FtpStatusCode.FileCommandPending)
 943                                         throw CreateExceptionFromResponse (status);
 944                         }
 945
 946                         if (method != WebRequestMethods.Ftp.ListDirectory && method != WebRequestMethods.Ftp.ListDirectoryDetails &&
 947                             method != WebRequestMethods.Ftp.UploadFileWithUniqueName) {
 948                                 status = SendCommand (method, file_name);
 949                         } else {
 950                                 status = SendCommand (method);
 951                         }
 952
 953                         if (status.StatusCode != FtpStatusCode.OpeningData && status.StatusCode != FtpStatusCode.DataAlreadyOpen)
 954                                 throw CreateExceptionFromResponse (status);
 955
 956                         if (usePassive) {
 957                                 dataSocket = s;
 958                         }
 959                         else {
 960
 961                                 // Active connection (use Socket.Blocking to true)
 962                                 Socket incoming = null;
 963                                 try {
 964                                         incoming = s.Accept ();
 965                                 }
 966                                 catch (SocketException) {
 967                                         s.Close ();
 968                                         if (incoming != null)
 969                                                 incoming.Close ();
 970
 971                                         throw new ProtocolViolationException ("Server commited a protocol violation.");
 972                                 }
 973
 974                                 s.Close ();
 975                                 dataSocket = incoming;
 976                         }
 977
 978                         if (EnableSsl) {
 979                                 InitiateSecureConnection (ref controlStream);
 980                                 controlReader = new StreamReader (controlStream, Encoding.ASCII);
 981                         }
 982
 983                         ftpResponse.UpdateStatus (status);
 984                 }
 985
 986                 void Authenticate ()
 987                 {
 988                         string username = null;
 989                         string password = null;
 990                         string domain = null;
 991
 992                         if (credentials != null) {
 993                                 username = credentials.UserName;
 994                                 password = credentials.Password;
 995                                 domain = credentials.Domain;
 996                         }
 997
 998                         if (username == null)
 999                                 username = "anonymous";
1000                         if (password == null)
1001                                 password = "@anonymous";
1002                         if (!string.IsNullOrEmpty (domain))
1003                                 username = domain + '\\' + username;
1004
1005                         // Connect to server and get banner message
1006                         FtpStatus status = GetResponseStatus ();
1007                         ftpResponse.BannerMessage = status.StatusDescription;
1008
1009                         if (EnableSsl) {
1010                                 InitiateSecureConnection (ref controlStream);
1011                                 controlReader = new StreamReader (controlStream, Encoding.ASCII);
1012                         }
1013
1014                         if (status.StatusCode != FtpStatusCode.SendUserCommand)
1015                                 throw CreateExceptionFromResponse (status);
1016
1017                         status = SendCommand (UserCommand, username);
1018
1019                         switch (status.StatusCode) {
1020                         case FtpStatusCode.SendPasswordCommand:
1021                                 status = SendCommand (PasswordCommand, password);
1022                                 if (status.StatusCode != FtpStatusCode.LoggedInProceed)
1023                                         throw CreateExceptionFromResponse (status);
1024                                 break;
1025                         case FtpStatusCode.LoggedInProceed:
1026                                 break;
1027                         default:
1028                                 throw CreateExceptionFromResponse (status);
1029                         }
1030
1031                         ftpResponse.WelcomeMessage = status.StatusDescription;
1032                         ftpResponse.UpdateStatus (status);
1033                 }
1034
1035                 FtpStatus SendCommand (string command, params string [] parameters) {
1036                         return SendCommand (true, command, parameters);
1037                 }
1038
1039                 FtpStatus SendCommand (bool waitResponse, string command, params string [] parameters)
1040                 {
1041                         byte [] cmd;
1042                         string commandString = command;
1043                         if (parameters.Length > 0)
1044                                 commandString += " " + String.Join (" ", parameters);
1045
1046                         commandString += EOL;
1047                         cmd = Encoding.ASCII.GetBytes (commandString);
1048                         try {
1049                                 controlStream.Write (cmd, 0, cmd.Length);
1050                         } catch (IOException) {
1051                                 //controlStream.Close ();
1052                                 return new FtpStatus(FtpStatusCode.ServiceNotAvailable, "Write failed");
1053                         }
1054
1055                         if(!waitResponse)
1056                                 return null;
1057
1058                         FtpStatus result = GetResponseStatus ();
1059                         if (ftpResponse != null)
1060                                 ftpResponse.UpdateStatus (result);
1061                         return result;
1062                 }
1063
1064                 internal static FtpStatus ServiceNotAvailable ()
1065                 {
1066                         return new FtpStatus (FtpStatusCode.ServiceNotAvailable, Locale.GetText ("Invalid response from server"));
1067                 }
1068
1069                 internal FtpStatus GetResponseStatus ()
1070                 {
1071                         while (true) {
1072                                 string response = null;
1073
1074                                 try {
1075                                         response = controlReader.ReadLine ();
1076                                 } catch (IOException) {
1077                                 }
1078
1079                                 if (response == null || response.Length < 3)
1080                                         return ServiceNotAvailable ();
1081
1082                                 int code;
1083                                 if (!Int32.TryParse (response.Substring (0, 3), out code))
1084                                         return ServiceNotAvailable ();
1085
1086                                 if (response.Length > 3 && response [3] == '-'){
1087                                         string line = null;
1088                                         string find = code.ToString() + ' ';
1089                                         while (true){
1090                                                 try {
1091                                                         line = controlReader.ReadLine();
1092                                                 } catch (IOException) {
1093                                                 }
1094                                                 if (line == null)
1095                                                         return ServiceNotAvailable ();
1096
1097                                                 response += Environment.NewLine + line;
1098
1099                                                 if (line.StartsWith(find, StringComparison.Ordinal))
1100                                                         break;
1101                                         }
1102                                 }
1103                                 return new FtpStatus ((FtpStatusCode) code, response);
1104                         }
1105                 }
1106
1107                 private void InitiateSecureConnection (ref NetworkStream stream) {
1108                         FtpStatus status = SendCommand (AuthCommand, "TLS");
1109
1110                         if (status.StatusCode != FtpStatusCode.ServerWantsSecureSession) {
1111                                 throw CreateExceptionFromResponse (status);
1112                         }
1113
1114                         ChangeToSSLSocket (ref stream);
1115                 }
1116
1117                 internal static bool ChangeToSSLSocket (ref NetworkStream stream) {
1118 #if TARGET_JVM
1119                         stream.ChangeToSSLSocket ();
1120                         return true;
1121 #else
1122                         throw new NotImplementedException ();
1123 #endif
1124                 }
1125
1126                 bool InFinalState () {
1127                         return (State == RequestState.Aborted || State == RequestState.Error || State == RequestState.Finished);
1128                 }
1129
1130                 bool InProgress () {
1131                         return (State != RequestState.Before && !InFinalState ());
1132                 }
1133
1134                 internal void CheckIfAborted () {
1135                         if (State == RequestState.Aborted)
1136                                 throw new WebException ("Request aborted", WebExceptionStatus.RequestCanceled);
1137                 }
1138
1139                 void CheckFinalState () {
1140                         if (InFinalState ())
1141                                 throw new InvalidOperationException ("Cannot change final state");
1142                 }
1143         }
1144 }
1145
1146 #endif
1147