mcs/class/System.ServiceModel/System.ServiceModel.Dispatcher/ChannelDispatcher.cs

   1 //
   2 // ChannelDispatcher.cs
   3 //
   4 // Author:
   5 //      Atsushi Enomoto <atsushi@ximian.com>
   6 //
   7 // Copyright (C) 2005,2009 Novell, Inc.  http://www.novell.com
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28 using System;
  29 using System.Collections.Generic;
  30 using System.Collections.ObjectModel;
  31 using System.Reflection;
  32 using System.ServiceModel.Channels;
  33 using System.Threading;
  34 using System.Transactions;
  35 using System.ServiceModel;
  36 using System.ServiceModel.Description;
  37
  38 namespace System.ServiceModel.Dispatcher
  39 {
  40         public class ChannelDispatcher : ChannelDispatcherBase
  41         {
  42                 class EndpointDispatcherCollection : SynchronizedCollection<EndpointDispatcher>
  43                 {
  44                         public EndpointDispatcherCollection (ChannelDispatcher owner)
  45                         {
  46                                 this.owner = owner;
  47                         }
  48
  49                         ChannelDispatcher owner;
  50
  51                         protected override void ClearItems ()
  52                         {
  53                                 foreach (var ed in this)
  54                                         ed.ChannelDispatcher = null;
  55                                 base.ClearItems ();
  56                         }
  57
  58                         protected override void InsertItem (int index, EndpointDispatcher item)
  59                         {
  60                                 item.ChannelDispatcher = owner;
  61                                 base.InsertItem (index, item);
  62                         }
  63
  64                         protected override void RemoveItem (int index)
  65                         {
  66                                 if (index < Count)
  67                                         this [index].ChannelDispatcher = null;
  68                                 base.RemoveItem (index);
  69                         }
  70
  71                         protected override void SetItem (int index, EndpointDispatcher item)
  72                         {
  73                                 item.ChannelDispatcher = owner;
  74                                 base.SetItem (index, item);
  75                         }
  76                 }
  77
  78                 ServiceHostBase host;
  79
  80                 string binding_name;
  81                 Collection<IErrorHandler> error_handlers
  82                         = new Collection<IErrorHandler> ();
  83                 IChannelListener listener;
  84                 internal IDefaultCommunicationTimeouts timeouts; // FIXME: remove internal
  85                 MessageVersion message_version;
  86                 bool receive_sync, include_exception_detail_in_faults,
  87                         manual_addressing, is_tx_receive;
  88                 int max_tx_batch_size;
  89                 SynchronizedCollection<IChannelInitializer> initializers
  90                         = new SynchronizedCollection<IChannelInitializer> ();
  91                 IsolationLevel tx_isolation_level;
  92                 TimeSpan tx_timeout;
  93                 ServiceThrottle throttle;
  94
  95                 Guid identifier = Guid.NewGuid ();
  96                 ManualResetEvent async_event = new ManualResetEvent (false);
  97
  98                 ListenerLoopManager loop_manager;
  99                 SynchronizedCollection<EndpointDispatcher> endpoints;
 100
 101                 [MonoTODO ("get binding info from config")]
 102                 public ChannelDispatcher (IChannelListener listener)
 103                         : this (listener, null)
 104                 {
 105                 }
 106
 107                 public ChannelDispatcher (
 108                         IChannelListener listener, string bindingName)
 109                         : this (listener, bindingName, null)
 110                 {
 111                 }
 112
 113                 public ChannelDispatcher (
 114                         IChannelListener listener, string bindingName,
 115                         IDefaultCommunicationTimeouts timeouts)
 116                 {
 117                         if (listener == null)
 118                                 throw new ArgumentNullException ("listener");
 119                         Init (listener, bindingName, timeouts);
 120                 }
 121
 122                 private void Init (IChannelListener listener, string bindingName,
 123                         IDefaultCommunicationTimeouts timeouts)
 124                 {
 125                         this.listener = listener;
 126                         this.binding_name = bindingName;
 127                         // IChannelListener is often a ChannelListenerBase
 128                         // which implements IDefaultCommunicationTimeouts.
 129                         this.timeouts = timeouts ?? listener as IDefaultCommunicationTimeouts ?? DefaultCommunicationTimeouts.Instance;
 130                         endpoints = new EndpointDispatcherCollection (this);
 131                 }
 132
 133                 internal EndpointDispatcher InitializeServiceEndpoint (Type serviceType, ServiceEndpoint se)
 134                 {
 135                         this.MessageVersion = se.Binding.MessageVersion;
 136                         if (this.MessageVersion == null)
 137                                 this.MessageVersion = MessageVersion.Default;
 138
 139                         //Attach one EndpointDispacher to the ChannelDispatcher
 140                         EndpointDispatcher ed = new EndpointDispatcher (se.Address, se.Contract.Name, se.Contract.Namespace);
 141                         this.Endpoints.Add (ed);
 142                         ed.InitializeServiceEndpoint (false, serviceType, se);
 143                         return ed;
 144                 }
 145
 146                 public string BindingName {
 147                         get { return binding_name; }
 148                 }
 149
 150                 public SynchronizedCollection<IChannelInitializer> ChannelInitializers {
 151                         get { return initializers; }
 152                 }
 153
 154                 protected internal override TimeSpan DefaultCloseTimeout {
 155                         get { return timeouts.CloseTimeout; }
 156                 }
 157
 158                 protected internal override TimeSpan DefaultOpenTimeout {
 159                         get { return timeouts.OpenTimeout; }
 160                 }
 161
 162                 public Collection<IErrorHandler> ErrorHandlers {
 163                         get { return error_handlers; }
 164                 }
 165
 166                 public SynchronizedCollection<EndpointDispatcher> Endpoints {
 167                         get { return endpoints; }
 168                 }
 169
 170                 [MonoTODO]
 171                 public bool IsTransactedAccept {
 172                         get { throw new NotImplementedException (); }
 173                 }
 174
 175                 public bool IsTransactedReceive {
 176                         get { return is_tx_receive; }
 177                         set { is_tx_receive = value; }
 178                 }
 179
 180                 public bool ManualAddressing {
 181                         get { return manual_addressing; }
 182                         set { manual_addressing = value; }
 183                 }
 184
 185                 public int MaxTransactedBatchSize {
 186                         get { return max_tx_batch_size; }
 187                         set { max_tx_batch_size = value; }
 188                 }
 189
 190                 public override ServiceHostBase Host {
 191                         get { return host; }
 192                 }
 193
 194                 public override IChannelListener Listener {
 195                         get { return listener; }
 196                 }
 197
 198                 public MessageVersion MessageVersion {
 199                         get { return message_version; }
 200                         set { message_version = value; }
 201                 }
 202
 203                 public bool ReceiveSynchronously {
 204                         get { return receive_sync; }
 205                         set {
 206                                 ThrowIfDisposedOrImmutable ();
 207                                 receive_sync = value;
 208                         }
 209                 }
 210
 211                 public bool IncludeExceptionDetailInFaults {
 212                         get { return include_exception_detail_in_faults; }
 213                         set { include_exception_detail_in_faults = value; }
 214                 }
 215
 216                 public ServiceThrottle ServiceThrottle {
 217                         get { return throttle; }
 218                         set { throttle = value; }
 219                 }
 220
 221                 public IsolationLevel TransactionIsolationLevel {
 222                         get { return tx_isolation_level; }
 223                         set { tx_isolation_level = value; }
 224                 }
 225
 226                 public TimeSpan TransactionTimeout {
 227                         get { return tx_timeout; }
 228                         set { tx_timeout = value; }
 229                 }
 230
 231                 protected internal override void Attach (ServiceHostBase host)
 232                 {
 233                         this.host = host;
 234                 }
 235
 236                 public override void CloseInput ()
 237                 {
 238                         if (loop_manager != null)
 239                                 loop_manager.CloseInput ();
 240                 }
 241
 242                 protected internal override void Detach (ServiceHostBase host)
 243                 {
 244                         this.host = null;
 245                 }
 246
 247                 protected override void OnAbort ()
 248                 {
 249                         if (loop_manager != null)
 250                                 loop_manager.Stop (TimeSpan.FromTicks (1));
 251                 }
 252
 253                 Action<TimeSpan> open_delegate;
 254                 Action<TimeSpan> close_delegate;
 255
 256                 protected override IAsyncResult OnBeginClose (TimeSpan timeout,
 257                         AsyncCallback callback, object state)
 258                 {
 259                         if (close_delegate == null)
 260                                 close_delegate = new Action<TimeSpan> (OnClose);
 261                         return close_delegate.BeginInvoke (timeout, callback, state);
 262                 }
 263
 264                 protected override IAsyncResult OnBeginOpen (TimeSpan timeout,
 265                         AsyncCallback callback, object state)
 266                 {
 267                         if (open_delegate == null)
 268                                 open_delegate = new Action<TimeSpan> (OnOpen);
 269                         return open_delegate.BeginInvoke (timeout, callback, state);
 270                 }
 271
 272                 protected override void OnClose (TimeSpan timeout)
 273                 {
 274                         if (loop_manager != null)
 275                                 loop_manager.Stop (timeout);
 276                 }
 277
 278                 protected override void OnClosed ()
 279                 {
 280                         if (host != null)
 281                                 host.ChannelDispatchers.Remove (this);
 282                         base.OnClosed ();
 283                 }
 284
 285                 protected override void OnEndClose (IAsyncResult result)
 286                 {
 287                         close_delegate.EndInvoke (result);
 288                 }
 289
 290                 protected override void OnEndOpen (IAsyncResult result)
 291                 {
 292                         open_delegate.EndInvoke (result);
 293                 }
 294
 295                 protected override void OnOpen (TimeSpan timeout)
 296                 {
 297                         if (Host == null || MessageVersion == null)
 298                                 throw new InvalidOperationException ("Service host is not attached to this ChannelDispatcher.");
 299
 300                         loop_manager.Setup (timeout);
 301                 }
 302
 303                 protected override void OnOpening ()
 304                 {
 305                         base.OnOpening ();
 306                         loop_manager = new ListenerLoopManager (this);
 307                 }
 308
 309                 protected override void OnOpened ()
 310                 {
 311                         base.OnOpened ();
 312                         StartLoop ();
 313                 }
 314
 315                 void StartLoop ()
 316                 {
 317                         // FIXME: not sure if it should be filled here.
 318                         if (ServiceThrottle == null)
 319                                 ServiceThrottle = new ServiceThrottle ();
 320
 321                         loop_manager.Start ();
 322                 }
 323         }
 324
 325                 // isolated from ChannelDispatcher
 326                 class ListenerLoopManager
 327                 {
 328                         ChannelDispatcher owner;
 329                         AutoResetEvent throttle_wait_handle = new AutoResetEvent (false);
 330                         AutoResetEvent creator_handle = new AutoResetEvent (false);
 331                         ManualResetEvent stop_handle = new ManualResetEvent (false);
 332                         bool loop;
 333                         Thread loop_thread;
 334                         DateTime close_started;
 335                         TimeSpan close_timeout;
 336                         Func<IAsyncResult> channel_acceptor;
 337                         List<IChannel> channels = new List<IChannel> ();
 338                         AddressFilterMode address_filter_mode;
 339
 340                         public ListenerLoopManager (ChannelDispatcher owner)
 341                         {
 342                                 this.owner = owner;
 343                                 var sba = owner.Host != null ? owner.Host.Description.Behaviors.Find<ServiceBehaviorAttribute> () : null;
 344                                 if (sba != null)
 345                                         address_filter_mode = sba.AddressFilterMode;
 346                         }
 347
 348                         public void Setup (TimeSpan openTimeout)
 349                         {
 350                                 if (owner.Listener.State != CommunicationState.Opened)
 351                                         owner.Listener.Open (openTimeout);
 352
 353                                 // It is tested at Open(), but strangely it is not instantiated at this point.
 354                                 foreach (var ed in owner.Endpoints)
 355                                         if (ed.DispatchRuntime.InstanceContextProvider == null && (ed.DispatchRuntime.Type == null || ed.DispatchRuntime.Type.GetConstructor (Type.EmptyTypes) == null))
 356                                                 throw new InvalidOperationException ("There is no default constructor for the service Type in the DispatchRuntime");
 357                                 SetupChannelAcceptor ();
 358                         }
 359
 360                         public void Start ()
 361                         {
 362                                 if (loop_thread == null)
 363                                         loop_thread = new Thread (new ThreadStart (Loop));
 364                                 loop_thread.Start ();
 365                         }
 366
 367                         Func<IAsyncResult> CreateAcceptor<TChannel> (IChannelListener l) where TChannel : class, IChannel
 368                         {
 369                                 IChannelListener<TChannel> r = l as IChannelListener<TChannel>;
 370                                 if (r == null)
 371                                         return null;
 372                                 AsyncCallback callback = delegate (IAsyncResult result) {
 373                                         try {
 374                                                 ChannelAccepted (r.EndAcceptChannel (result));
 375                                         } catch (Exception ex) {
 376                                                 Console.WriteLine ("Exception during finishing channel acceptance.");
 377                                                 Console.WriteLine (ex);
 378                                                 creator_handle.Set ();
 379                                         }
 380                                 };
 381                                 return delegate {
 382                                         try {
 383                                                 return r.BeginAcceptChannel (callback, null);
 384                                         } catch (Exception ex) {
 385                                                 Console.WriteLine ("Exception during accepting channel.");
 386                                                 Console.WriteLine (ex);
 387                                                 throw;
 388                                         }
 389                                 };
 390                         }
 391
 392                         void SetupChannelAcceptor ()
 393                         {
 394                                 var l = owner.Listener;
 395                                 channel_acceptor =
 396                                         CreateAcceptor<IReplyChannel> (l) ??
 397                                         CreateAcceptor<IReplySessionChannel> (l) ??
 398                                         CreateAcceptor<IInputChannel> (l) ??
 399                                         CreateAcceptor<IInputSessionChannel> (l) ??
 400                                         CreateAcceptor<IDuplexChannel> (l) ??
 401                                         CreateAcceptor<IDuplexSessionChannel> (l);
 402                                 if (channel_acceptor == null)
 403                                         throw new InvalidOperationException (String.Format ("Unrecognized channel listener type: {0}", l.GetType ()));
 404                         }
 405
 406                         public void Stop (TimeSpan timeout)
 407                         {
 408                                 if (loop_thread == null)
 409                                         return;
 410
 411                                 close_started = DateTime.Now;
 412                                 close_timeout = timeout;
 413                                 loop = false;
 414                                 creator_handle.Set ();
 415                                 throttle_wait_handle.Set (); // break primary loop
 416                                 if (stop_handle != null) {
 417                                         stop_handle.WaitOne (timeout > TimeSpan.Zero ? timeout : TimeSpan.FromTicks (1));
 418                                         stop_handle.Close ();
 419                                         stop_handle = null;
 420                                 }
 421                                 if (owner.Listener.State != CommunicationState.Closed) {
 422                                         // FIXME: log it
 423                                         Console.WriteLine ("Channel listener '{0}' is not closed. Aborting.", owner.Listener.GetType ());
 424                                         owner.Listener.Abort ();
 425                                 }
 426                                 if (loop_thread != null && loop_thread.IsAlive)
 427                                         loop_thread.Abort ();
 428                                 loop_thread = null;
 429                         }
 430
 431                         public void CloseInput ()
 432                         {
 433                                 foreach (var ch in channels.ToArray ()) {
 434                                         if (ch.State == CommunicationState.Closed)
 435                                                 channels.Remove (ch); // zonbie, if exists
 436                                         else {
 437                                                 try {
 438                                                         ch.Close (close_timeout - (DateTime.Now - close_started));
 439                                                 } catch (Exception ex) {
 440                                                         // FIXME: log it.
 441                                                         Console.WriteLine (ex);
 442                                                         ch.Abort ();
 443                                                 }
 444                                         }
 445                                 }
 446                         }
 447
 448                         void Loop ()
 449                         {
 450                                 try {
 451                                         LoopCore ();
 452                                 } catch (Exception ex) {
 453                                         // FIXME: log it
 454                                         Console.WriteLine ("ListenerLoopManager caught an exception inside dispatcher loop, which is likely thrown by the channel listener {0}", owner.Listener);
 455                                         Console.WriteLine (ex);
 456                                 } finally {
 457                                         if (stop_handle != null)
 458                                                 stop_handle.Set ();
 459                                 }
 460                         }
 461
 462                         void LoopCore ()
 463                         {
 464                                 loop = true;
 465
 466                                 // FIXME: use WaitForChannel() for (*only* for) transacted channel listeners.
 467                                 // http://social.msdn.microsoft.com/Forums/en-US/wcf/thread/3faa4a5e-8602-4dbe-a181-73b3f581835e
 468
 469                                 while (loop) {
 470                                         // FIXME: enable throttling and allow more than one connection to process at a time.
 471                                         while (loop && channels.Count < 1) {
 472 //                                      while (loop && channels.Count < owner.ServiceThrottle.MaxConcurrentSessions) {
 473                                                 channel_acceptor ();
 474                                                 creator_handle.WaitOne (); // released by ChannelAccepted()
 475                                         }
 476                                         if (!loop)
 477                                                 break;
 478                                         throttle_wait_handle.WaitOne (); // released by IChannel.Close()
 479                                 }
 480                                 try {
 481                                         owner.Listener.Close ();
 482                                 } finally {
 483                                         // make sure to close both listener and channels.
 484                                         owner.CloseInput ();
 485                                 }
 486                         }
 487
 488                         void ChannelAccepted (IChannel ch)
 489                         {
 490                         try {
 491                                 if (ch == null) // could happen when it was aborted
 492                                         return;
 493                                 if (!loop) {
 494                                         var dis = ch as IDisposable;
 495                                         if (dis != null)
 496                                                 dis.Dispose ();
 497                                         return;
 498                                 }
 499
 500                                 lock (channels)
 501                                         channels.Add (ch);
 502                                 ch.Opened += delegate {
 503                                         ch.Faulted += delegate {
 504                                                 lock (channels)
 505                                                         if (channels.Contains (ch))
 506                                                                 channels.Remove (ch);
 507                                                 throttle_wait_handle.Set (); // release loop wait lock.
 508                                                 };
 509                                         ch.Closed += delegate {
 510                                                 lock (channels)
 511                                                         if (channels.Contains (ch))
 512                                                                 channels.Remove (ch);
 513                                                 throttle_wait_handle.Set (); // release loop wait lock.
 514                                                 };
 515                                         };
 516                                 ch.Open ();
 517                         } finally {
 518                                 creator_handle.Set ();
 519                         }
 520
 521                                 ProcessRequestOrInput (ch);
 522                         }
 523
 524                         void ProcessRequestOrInput (IChannel ch)
 525                         {
 526                                 var reply = ch as IReplyChannel;
 527                                 var input = ch as IInputChannel;
 528
 529                                 if (reply != null) {
 530                                         if (owner.ReceiveSynchronously) {
 531                                                 RequestContext rc;
 532                                                 if (reply.TryReceiveRequest (owner.timeouts.ReceiveTimeout, out rc))
 533                                                         ProcessRequest (reply, rc);
 534                                         } else {
 535                                                 reply.BeginTryReceiveRequest (owner.timeouts.ReceiveTimeout, TryReceiveRequestDone, reply);
 536                                         }
 537                                 } else if (input != null) {
 538                                         if (owner.ReceiveSynchronously) {
 539                                                 Message msg;
 540                                                 if (input.TryReceive (owner.timeouts.ReceiveTimeout, out msg))
 541                                                         ProcessInput (input, msg);
 542                                         } else {
 543                                                 input.BeginTryReceive (owner.timeouts.ReceiveTimeout, TryReceiveDone, input);
 544                                         }
 545                                 }
 546                         }
 547
 548                         void TryReceiveRequestDone (IAsyncResult result)
 549                         {
 550                                 RequestContext rc;
 551                                 var reply = (IReplyChannel) result.AsyncState;
 552                                 if (reply.EndTryReceiveRequest (result, out rc))
 553                                         ProcessRequest (reply, rc);
 554                                 else
 555                                         reply.Close ();
 556                         }
 557
 558                         void TryReceiveDone (IAsyncResult result)
 559                         {
 560                                 Message msg;
 561                                 var input = (IInputChannel) result.AsyncState;
 562                                 if (input.EndTryReceive (result, out msg))
 563                                         ProcessInput (input, msg);
 564                                 else
 565                                         input.Close ();
 566                         }
 567
 568                         void ProcessRequest (IReplyChannel reply, RequestContext rc)
 569                         {
 570                                 var req = rc.RequestMessage;
 571                                 try {
 572                                         var ed = FindEndpointDispatcher (req);
 573                                         new InputOrReplyRequestProcessor (ed.DispatchRuntime, reply).ProcessReply (rc);
 574                                 } catch (Exception ex) {
 575                                         // FIXME: log it.
 576                                         Console.WriteLine (ex);
 577
 578                                         var conv = reply.GetProperty<FaultConverter> () ?? FaultConverter.GetDefaultFaultConverter (rc.RequestMessage.Version);
 579                                         Message res;
 580                                         if (!conv.TryCreateFaultMessage (ex, out res))
 581                                                 res = Message.CreateMessage (req.Version, new FaultCode ("Receiver"), ex.Message, req.Version.Addressing.FaultNamespace);
 582                                         rc.Reply (res);
 583                                 } finally {
 584                                         if (rc != null)
 585                                                 rc.Close ();
 586                                         // unless it is closed by session/call manager, move it back to the loop to receive the next message.
 587                                         if (loop && reply.State != CommunicationState.Closed)
 588                                                 ProcessRequestOrInput (reply);
 589                                 }
 590                         }
 591
 592                         void ProcessInput (IInputChannel input, Message message)
 593                         {
 594                                 try {
 595                                         EndpointDispatcher candidate = null;
 596                                         candidate = FindEndpointDispatcher (message);
 597                                         new InputOrReplyRequestProcessor (candidate.DispatchRuntime, input).
 598                                                 ProcessInput (message);
 599                                 }
 600                                 catch (Exception ex) {
 601                                         // FIXME: log it.
 602                                         Console.WriteLine (ex);
 603                                 } finally {
 604                                         // unless it is closed by session/call manager, move it back to the loop to receive the next message.
 605                                         if (loop && input.State != CommunicationState.Closed)
 606                                                 ProcessRequestOrInput (input);
 607                                 }
 608                         }
 609
 610                         EndpointDispatcher FindEndpointDispatcher (Message message) {
 611                                 EndpointDispatcher candidate = null;
 612                                 bool hasEndpointMatch = false;
 613                                 foreach (var endpoint in owner.Endpoints) {
 614                                         if (endpoint.AddressFilter.Match (message)) {
 615                                                 hasEndpointMatch = true;
 616                                                 if (!endpoint.ContractFilter.Match (message))
 617                                                         continue;
 618                                                 var newdis = endpoint;
 619                                                 if (candidate == null || candidate.FilterPriority < newdis.FilterPriority)
 620                                                         candidate = newdis;
 621                                                 else if (candidate.FilterPriority == newdis.FilterPriority)
 622                                                         throw new MultipleFilterMatchesException ();
 623                                         }
 624                                 }
 625                                 if (candidate == null && !hasEndpointMatch) {
 626                                         if (owner.Host != null)
 627                                                 owner.Host.OnUnknownMessageReceived (message);
 628                                         // we have to return a fault to the client anyways...
 629                                         throw new EndpointNotFoundException ();
 630                                 }
 631                                 else if (candidate == null)
 632                                         // FIXME: It is not a good place to check, but anyways detach this error from EndpointNotFoundException.
 633                                         throw new ActionNotSupportedException (String.Format ("Action '{0}' did not match any operations in the target contract", message.Headers.Action));
 634
 635                                 return candidate;
 636                         }
 637                 }
 638 }