2 // System.Net.FtpWebRequest.cs
5 // Carlos Alberto Cortez (calberto.cortez@gmail.com)
7 // (c) Copyright 2006 Novell, Inc. (http://www.novell.com)
13 using System.Net.Sockets;
15 using System.Threading;
16 using System.Net.Cache;
17 using System.Security.Cryptography.X509Certificates;
23 public sealed class FtpWebRequest : WebRequest
26 string file_name; // By now, used for upload
27 ServicePoint servicePoint;
29 NetworkStream controlStream;
30 StreamReader controlReader;
31 NetworkCredential credentials;
32 IPHostEntry hostEntry;
33 IPEndPoint localEndPoint;
36 int rwTimeout = 300000;
39 bool enableSsl = false;
40 bool usePassive = true;
41 bool keepAlive = false;
42 string method = WebRequestMethods.Ftp.DownloadFile;
44 object locker = new object ();
46 RequestState requestState = RequestState.Before;
47 FtpAsyncResult asyncResult;
48 FtpWebResponse ftpResponse;
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
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
96 internal FtpWebRequest (Uri uri)
98 this.requestUri = uri;
99 this.proxy = GlobalProxySelection.Select;
102 static Exception GetMustImplement ()
104 return new NotImplementedException ();
108 public X509CertificateCollection ClientCertificates
111 throw GetMustImplement ();
114 throw GetMustImplement ();
119 public override string ConnectionGroupName
122 throw GetMustImplement ();
125 throw GetMustImplement ();
129 public override string ContentType {
131 throw new NotSupportedException ();
134 throw new NotSupportedException ();
138 public override long ContentLength {
147 public long ContentOffset {
152 CheckRequestStarted ();
154 throw new ArgumentOutOfRangeException ();
160 public override ICredentials Credentials {
165 CheckRequestStarted ();
167 throw new ArgumentNullException ();
168 if (!(value is NetworkCredential))
169 throw new ArgumentException ();
171 credentials = value as NetworkCredential;
176 public static new RequestCachePolicy DefaultCachePolicy
179 throw GetMustImplement ();
182 throw GetMustImplement ();
186 public bool EnableSsl {
191 CheckRequestStarted ();
197 public override WebHeaderCollection Headers
200 throw GetMustImplement ();
203 throw GetMustImplement ();
207 public bool KeepAlive {
212 CheckRequestStarted ();
217 public override string Method {
222 CheckRequestStarted ();
224 throw new ArgumentNullException ("Method string cannot be null");
226 if (value.Length == 0 || Array.BinarySearch (supportedCommands, value) < 0)
227 throw new ArgumentException ("Method not supported", "value");
233 public override bool PreAuthenticate {
235 throw new NotSupportedException ();
238 throw new NotSupportedException ();
242 public override IWebProxy Proxy {
247 CheckRequestStarted ();
249 throw new ArgumentNullException ();
255 public int ReadWriteTimeout {
260 CheckRequestStarted ();
263 throw new ArgumentOutOfRangeException ();
269 public string RenameTo {
274 CheckRequestStarted ();
275 if (value == null || value.Length == 0)
276 throw new ArgumentException ("RenameTo value can't be null or empty", "RenameTo");
282 public override Uri RequestUri {
288 public ServicePoint ServicePoint {
290 return GetServicePoint ();
294 public bool UsePassive {
299 CheckRequestStarted ();
305 public override bool UseDefaultCredentials
308 throw GetMustImplement ();
311 throw GetMustImplement ();
315 public bool UseBinary {
319 CheckRequestStarted ();
324 public override int Timeout {
329 CheckRequestStarted ();
332 throw new ArgumentOutOfRangeException ();
340 return binary ? "I" : "A";
355 requestState = value;
360 public override void Abort () {
362 if (State == RequestState.TransferInProgress) {
363 /*FtpStatus status = */
364 SendCommand (false, AbortCommand);
367 if (!InFinalState ()) {
368 State = RequestState.Aborted;
369 ftpResponse = new FtpWebResponse (requestUri, method, FtpStatusCode.FileActionAborted, "Aborted by request");
374 public override IAsyncResult BeginGetResponse (AsyncCallback callback, object state) {
375 if (asyncResult != null && !asyncResult.IsCompleted) {
376 throw new InvalidOperationException ("Cannot re-call BeginGetRequestStream/BeginGetResponse while a previous call is still in progress");
381 asyncResult = new FtpAsyncResult (callback, state);
385 asyncResult.SetCompleted (true, ftpResponse);
387 if (State == RequestState.Before)
388 State = RequestState.Scheduled;
390 Thread thread = new Thread (ProcessRequest);
398 public override WebResponse EndGetResponse (IAsyncResult asyncResult) {
399 if (asyncResult == null)
400 throw new ArgumentNullException ("AsyncResult cannot be null!");
402 if (!(asyncResult is FtpAsyncResult) || asyncResult != this.asyncResult)
403 throw new ArgumentException ("AsyncResult is from another request!");
405 FtpAsyncResult asyncFtpResult = (FtpAsyncResult) asyncResult;
406 if (!asyncFtpResult.WaitUntilComplete (timeout, false)) {
408 throw new WebException ("Transfer timed out.", WebExceptionStatus.Timeout);
415 if (asyncFtpResult.GotException)
416 throw asyncFtpResult.Exception;
418 return asyncFtpResult.Response;
421 public override WebResponse GetResponse () {
422 IAsyncResult asyncResult = BeginGetResponse (null, null);
423 return EndGetResponse (asyncResult);
426 public override IAsyncResult BeginGetRequestStream (AsyncCallback callback, object state) {
427 if (method != WebRequestMethods.Ftp.UploadFile && method != WebRequestMethods.Ftp.UploadFileWithUniqueName &&
428 method != WebRequestMethods.Ftp.AppendFile)
429 throw new ProtocolViolationException ();
434 if (State != RequestState.Before)
435 throw new InvalidOperationException ("Cannot re-call BeginGetRequestStream/BeginGetResponse while a previous call is still in progress");
437 State = RequestState.Scheduled;
440 asyncResult = new FtpAsyncResult (callback, state);
441 Thread thread = new Thread (ProcessRequest);
447 public override Stream EndGetRequestStream (IAsyncResult asyncResult) {
448 if (asyncResult == null)
449 throw new ArgumentNullException ("asyncResult");
451 if (!(asyncResult is FtpAsyncResult))
452 throw new ArgumentException ("asyncResult");
454 if (State == RequestState.Aborted) {
455 throw new WebException ("Request aborted", WebExceptionStatus.RequestCanceled);
458 if (asyncResult != this.asyncResult)
459 throw new ArgumentException ("AsyncResult is from another request!");
461 FtpAsyncResult res = (FtpAsyncResult) asyncResult;
463 if (!res.WaitUntilComplete (timeout, false)) {
465 throw new WebException ("Request timed out");
468 if (res.GotException)
474 public override Stream GetRequestStream () {
475 IAsyncResult asyncResult = BeginGetRequestStream (null, null);
476 return EndGetRequestStream (asyncResult);
479 ServicePoint GetServicePoint ()
481 if (servicePoint == null)
482 servicePoint = ServicePointManager.FindServicePoint (requestUri, proxy);
487 // Probably move some code of command connection here
491 hostEntry = GetServicePoint ().HostEntry;
493 if (hostEntry == null) {
494 ftpResponse.UpdateStatus (new FtpStatus(FtpStatusCode.ActionAbortedLocalProcessingError, "Cannot resolve server name"));
495 throw new WebException ("The remote server name could not be resolved: " + requestUri,
496 null, WebExceptionStatus.NameResolutionFailure, ftpResponse);
500 void ProcessRequest () {
502 if (State == RequestState.Scheduled) {
503 ftpResponse = new FtpWebResponse (requestUri, method, keepAlive);
507 //State = RequestState.Finished;
508 //finalResponse = ftpResponse;
509 asyncResult.SetCompleted (false, ftpResponse);
511 catch (Exception e) {
512 State = RequestState.Error;
513 SetCompleteWithError (e);
518 FtpStatus status = GetResponseStatus ();
520 ftpResponse.UpdateStatus (status);
522 if (ftpResponse.IsFinal ()) {
523 State = RequestState.Finished;
527 asyncResult.SetCompleted (false, ftpResponse);
534 FtpStatus status = SendCommand (TypeCommand, DataType);
535 if ((int) status.StatusCode < 200 || (int) status.StatusCode >= 300)
536 throw CreateExceptionFromResponse (status);
540 string GetRemoteFolderPath (Uri uri)
543 string local_path = Uri.UnescapeDataString (uri.LocalPath);
544 if (initial_path == null) {
547 if (local_path [0] == '/')
548 local_path = local_path.Substring (1);
549 Uri initial = new Uri (initial_path);
550 result = new Uri (initial, local_path).LocalPath;
553 int last = result.LastIndexOf ('/');
557 return result.Substring (0, last + 1);
560 void CWDAndSetFileName (Uri uri)
562 string remote_folder = GetRemoteFolderPath (uri);
564 if (remote_folder != null) {
565 status = SendCommand (ChangeDir, remote_folder);
566 if ((int) status.StatusCode < 200 || (int) status.StatusCode >= 300)
567 throw CreateExceptionFromResponse (status);
569 int last = uri.LocalPath.LastIndexOf ('/');
571 file_name = Uri.UnescapeDataString (uri.LocalPath.Substring (last + 1));
576 void ProcessMethod ()
578 State = RequestState.Connecting;
582 OpenControlConnection ();
583 CWDAndSetFileName (requestUri);
587 // Open data connection and receive data
588 case WebRequestMethods.Ftp.DownloadFile:
589 case WebRequestMethods.Ftp.ListDirectory:
590 case WebRequestMethods.Ftp.ListDirectoryDetails:
593 // Open data connection and send data
594 case WebRequestMethods.Ftp.AppendFile:
595 case WebRequestMethods.Ftp.UploadFile:
596 case WebRequestMethods.Ftp.UploadFileWithUniqueName:
599 // Get info from control connection
600 case WebRequestMethods.Ftp.GetFileSize:
601 case WebRequestMethods.Ftp.GetDateTimestamp:
602 case WebRequestMethods.Ftp.PrintWorkingDirectory:
603 case WebRequestMethods.Ftp.MakeDirectory:
604 case WebRequestMethods.Ftp.Rename:
605 case WebRequestMethods.Ftp.DeleteFile:
606 ProcessSimpleMethod ();
608 default: // What to do here?
609 throw new Exception (String.Format ("Support for command {0} not implemented yet", method));
615 private void CloseControlConnection () {
616 SendCommand (QuitCommand);
617 controlStream.Close ();
620 private void CloseDataConnection () {
621 if(dataSocket != null)
625 private void CloseConnection () {
626 CloseControlConnection ();
627 CloseDataConnection ();
630 void ProcessSimpleMethod ()
632 State = RequestState.TransferInProgress;
636 if (method == WebRequestMethods.Ftp.PrintWorkingDirectory)
639 if (method == WebRequestMethods.Ftp.Rename)
640 method = RenameFromCommand;
642 status = SendCommand (method, file_name);
644 ftpResponse.Stream = new EmptyStream ();
646 string desc = status.StatusDescription;
649 case WebRequestMethods.Ftp.GetFileSize: {
650 if (status.StatusCode != FtpStatusCode.FileStatus)
651 throw CreateExceptionFromResponse (status);
655 for (i = 4, len = 0; i < desc.Length && Char.IsDigit (desc [i]); i++, len++)
659 throw new WebException ("Bad format for server response in " + method);
661 if (!Int64.TryParse (desc.Substring (4, len), out size))
662 throw new WebException ("Bad format for server response in " + method);
664 ftpResponse.contentLength = size;
667 case WebRequestMethods.Ftp.GetDateTimestamp:
668 if (status.StatusCode != FtpStatusCode.FileStatus)
669 throw CreateExceptionFromResponse (status);
670 ftpResponse.LastModified = DateTime.ParseExact (desc.Substring (4), "yyyyMMddHHmmss", null);
672 case WebRequestMethods.Ftp.MakeDirectory:
673 if (status.StatusCode != FtpStatusCode.PathnameCreated)
674 throw CreateExceptionFromResponse (status);
677 method = WebRequestMethods.Ftp.PrintWorkingDirectory;
679 if (status.StatusCode != FtpStatusCode.FileActionOK)
680 throw CreateExceptionFromResponse (status);
682 status = SendCommand (method);
684 if (status.StatusCode != FtpStatusCode.PathnameCreated)
685 throw CreateExceptionFromResponse (status);
687 case RenameFromCommand:
688 method = WebRequestMethods.Ftp.Rename;
689 if (status.StatusCode != FtpStatusCode.FileCommandPending)
690 throw CreateExceptionFromResponse (status);
691 // Pass an empty string if RenameTo wasn't specified
692 status = SendCommand (RenameToCommand, renameTo != null ? renameTo : String.Empty);
693 if (status.StatusCode != FtpStatusCode.FileActionOK)
694 throw CreateExceptionFromResponse (status);
696 case WebRequestMethods.Ftp.DeleteFile:
697 if (status.StatusCode != FtpStatusCode.FileActionOK) {
698 throw CreateExceptionFromResponse (status);
703 State = RequestState.Finished;
708 State = RequestState.OpeningData;
710 OpenDataConnection ();
712 State = RequestState.TransferInProgress;
713 requestStream = new FtpDataStream (this, dataSocket, false);
714 asyncResult.Stream = requestStream;
719 State = RequestState.OpeningData;
721 // Handle content offset
723 FtpStatus status = SendCommand (RestCommand, offset.ToString ());
725 if (status.StatusCode != FtpStatusCode.FileCommandPending)
726 throw CreateExceptionFromResponse (status);
729 OpenDataConnection ();
731 State = RequestState.TransferInProgress;
732 ftpResponse.Stream = new FtpDataStream (this, dataSocket, true);
735 void CheckRequestStarted ()
737 if (State != RequestState.Before)
738 throw new InvalidOperationException ("There is a request currently in progress");
741 void OpenControlConnection ()
744 foreach (IPAddress address in hostEntry.AddressList) {
745 sock = new Socket (address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
747 IPEndPoint remote = new IPEndPoint (address, requestUri.Port);
749 if (!ServicePoint.CallEndPointDelegate (sock, remote)) {
754 sock.Connect (remote);
755 localEndPoint = (IPEndPoint) sock.LocalEndPoint;
757 } catch (SocketException) {
764 // Couldn't connect to any address
766 throw new WebException ("Unable to connect to remote server", null,
767 WebExceptionStatus.UnknownError, ftpResponse);
769 controlStream = new NetworkStream (sock);
770 controlReader = new StreamReader (controlStream, Encoding.ASCII);
772 State = RequestState.Authenticating;
775 FtpStatus status = SendCommand ("OPTS", "utf8", "on");
776 // ignore status for OPTS
777 status = SendCommand (WebRequestMethods.Ftp.PrintWorkingDirectory);
778 initial_path = GetInitialPath (status);
781 static string GetInitialPath (FtpStatus status)
783 int s = (int) status.StatusCode;
784 if (s < 200 || s > 300 || status.StatusDescription.Length <= 4)
785 throw new WebException ("Error getting current directory: " + status.StatusDescription, null,
786 WebExceptionStatus.UnknownError, null);
788 string msg = status.StatusDescription.Substring (4);
790 msg = msg.Substring (1, msg.Length - 2);
792 if (!msg.EndsWith ("/"))
797 // Probably we could do better having here a regex
798 Socket SetupPassiveConnection (string statusDescription)
800 // Current response string
801 string response = statusDescription;
802 if (response.Length < 4)
803 throw new WebException ("Cannot open passive data connection");
805 // Look for first digit after code
807 for (i = 3; i < response.Length && !Char.IsDigit (response [i]); i++)
809 if (i >= response.Length)
810 throw new WebException ("Cannot open passive data connection");
813 string [] digits = response.Substring (i).Split (new char [] {','}, 6);
814 if (digits.Length != 6)
815 throw new WebException ("Cannot open passive data connection");
817 // Clean non-digits at the end of last element
819 for (j = digits [5].Length - 1; j >= 0 && !Char.IsDigit (digits [5][j]); j--)
822 throw new WebException ("Cannot open passive data connection");
824 digits [5] = digits [5].Substring (0, j + 1);
828 ip = IPAddress.Parse (String.Join (".", digits, 0, 4));
829 } catch (FormatException) {
830 throw new WebException ("Cannot open passive data connection");
835 if (!Int32.TryParse (digits [4], out p1) || !Int32.TryParse (digits [5], out p2))
836 throw new WebException ("Cannot open passive data connection");
838 port = (p1 << 8) + p2; // p1 * 256 + p2
839 //port = p1 * 256 + p2;
840 if (port < IPEndPoint.MinPort || port > IPEndPoint.MaxPort)
841 throw new WebException ("Cannot open passive data connection");
843 IPEndPoint ep = new IPEndPoint (ip, port);
844 Socket sock = new Socket (ep.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
847 } catch (SocketException) {
849 throw new WebException ("Cannot open passive data connection");
855 Exception CreateExceptionFromResponse (FtpStatus status)
857 FtpWebResponse ftpResponse = new FtpWebResponse (requestUri, method, status);
859 WebException exc = new WebException ("Server returned an error: " + status.StatusDescription,
860 null, WebExceptionStatus.ProtocolError, ftpResponse);
864 // Here we could also get a server error, so be cautious
865 internal void SetTransferCompleted ()
870 State = RequestState.Finished;
871 FtpStatus status = GetResponseStatus ();
872 ftpResponse.UpdateStatus (status);
877 void SetCompleteWithError (Exception exc)
879 if (asyncResult != null) {
880 asyncResult.SetCompleted (false, exc);
884 Socket InitDataConnection ()
889 status = SendCommand (PassiveCommand);
890 if (status.StatusCode != FtpStatusCode.EnteringPassive) {
891 throw CreateExceptionFromResponse (status);
894 return SetupPassiveConnection (status.StatusDescription);
897 // Open a socket to listen the server's connection
898 Socket sock = new Socket (AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
900 sock.Bind (new IPEndPoint (localEndPoint.Address, 0));
901 sock.Listen (1); // We only expect a connection from server
903 } catch (SocketException e) {
906 throw new WebException ("Couldn't open listening socket on client", e);
909 IPEndPoint ep = (IPEndPoint) sock.LocalEndPoint;
910 string ipString = ep.Address.ToString ().Replace ('.', ',');
911 int h1 = ep.Port >> 8; // ep.Port / 256
912 int h2 = ep.Port % 256;
914 string portParam = ipString + "," + h1 + "," + h2;
915 status = SendCommand (PortCommand, portParam);
917 if (status.StatusCode != FtpStatusCode.CommandOK) {
919 throw (CreateExceptionFromResponse (status));
925 void OpenDataConnection ()
929 Socket s = InitDataConnection ();
931 if (method != WebRequestMethods.Ftp.ListDirectory && method != WebRequestMethods.Ftp.ListDirectoryDetails &&
932 method != WebRequestMethods.Ftp.UploadFileWithUniqueName) {
933 status = SendCommand (method, file_name);
935 status = SendCommand (method);
938 if (status.StatusCode != FtpStatusCode.OpeningData && status.StatusCode != FtpStatusCode.DataAlreadyOpen)
939 throw CreateExceptionFromResponse (status);
946 // Active connection (use Socket.Blocking to true)
947 Socket incoming = null;
949 incoming = s.Accept ();
951 catch (SocketException) {
953 if (incoming != null)
956 throw new ProtocolViolationException ("Server commited a protocol violation.");
960 dataSocket = incoming;
964 InitiateSecureConnection (ref controlStream);
965 controlReader = new StreamReader (controlStream, Encoding.ASCII);
968 ftpResponse.UpdateStatus (status);
973 string username = null;
974 string password = null;
975 string domain = null;
977 if (credentials != null) {
978 username = credentials.UserName;
979 password = credentials.Password;
980 domain = credentials.Domain;
983 if (username == null)
984 username = "anonymous";
985 if (password == null)
986 password = "@anonymous";
987 if (!string.IsNullOrEmpty (domain))
988 username = domain + '\\' + username;
990 // Connect to server and get banner message
991 FtpStatus status = GetResponseStatus ();
992 ftpResponse.BannerMessage = status.StatusDescription;
995 InitiateSecureConnection (ref controlStream);
996 controlReader = new StreamReader (controlStream, Encoding.ASCII);
999 if (status.StatusCode != FtpStatusCode.SendUserCommand)
1000 throw CreateExceptionFromResponse (status);
1002 status = SendCommand (UserCommand, username);
1004 switch (status.StatusCode) {
1005 case FtpStatusCode.SendPasswordCommand:
1006 status = SendCommand (PasswordCommand, password);
1007 if (status.StatusCode != FtpStatusCode.LoggedInProceed)
1008 throw CreateExceptionFromResponse (status);
1010 case FtpStatusCode.LoggedInProceed:
1013 throw CreateExceptionFromResponse (status);
1016 ftpResponse.WelcomeMessage = status.StatusDescription;
1017 ftpResponse.UpdateStatus (status);
1020 FtpStatus SendCommand (string command, params string [] parameters) {
1021 return SendCommand (true, command, parameters);
1024 FtpStatus SendCommand (bool waitResponse, string command, params string [] parameters)
1027 string commandString = command;
1028 if (parameters.Length > 0)
1029 commandString += " " + String.Join (" ", parameters);
1031 commandString += EOL;
1032 cmd = Encoding.ASCII.GetBytes (commandString);
1034 controlStream.Write (cmd, 0, cmd.Length);
1035 } catch (IOException) {
1036 //controlStream.Close ();
1037 return new FtpStatus(FtpStatusCode.ServiceNotAvailable, "Write failed");
1043 FtpStatus result = GetResponseStatus ();
1044 if (ftpResponse != null)
1045 ftpResponse.UpdateStatus (result);
1049 internal static FtpStatus ServiceNotAvailable ()
1051 return new FtpStatus (FtpStatusCode.ServiceNotAvailable, Locale.GetText ("Invalid response from server"));
1054 internal FtpStatus GetResponseStatus ()
1057 string response = null;
1060 response = controlReader.ReadLine ();
1061 } catch (IOException) {
1064 if (response == null || response.Length < 3)
1065 return ServiceNotAvailable ();
1068 if (!Int32.TryParse (response.Substring (0, 3), out code))
1069 return ServiceNotAvailable ();
1071 if (response [3] == '-'){
1073 string find = code.ToString() + ' ';
1076 line = controlReader.ReadLine();
1077 } catch (IOException) {
1080 return ServiceNotAvailable ();
1082 response += Environment.NewLine + line;
1084 if (line.StartsWith(find, StringComparison.Ordinal))
1088 return new FtpStatus ((FtpStatusCode) code, response);
1092 private void InitiateSecureConnection (ref NetworkStream stream) {
1093 FtpStatus status = SendCommand (AuthCommand, "TLS");
1095 if (status.StatusCode != FtpStatusCode.ServerWantsSecureSession) {
1096 throw CreateExceptionFromResponse (status);
1099 ChangeToSSLSocket (ref stream);
1102 internal static bool ChangeToSSLSocket (ref NetworkStream stream) {
1104 stream.ChangeToSSLSocket ();
1107 throw new NotImplementedException ();
1111 bool InFinalState () {
1112 return (State == RequestState.Aborted || State == RequestState.Error || State == RequestState.Finished);
1115 bool InProgress () {
1116 return (State != RequestState.Before && !InFinalState ());
1119 internal void CheckIfAborted () {
1120 if (State == RequestState.Aborted)
1121 throw new WebException ("Request aborted", WebExceptionStatus.RequestCanceled);
1124 void CheckFinalState () {
1125 if (InFinalState ())
1126 throw new InvalidOperationException ("Cannot change final state");
1129 class EmptyStream : MemoryStream
1131 internal EmptyStream ()
1132 : base (new byte [0], false) {