mcs/class/corlib/System.Runtime.Remoting/RemotingServices.cs

   1 //
   2 // System.Runtime.Remoting.RemotingServices.cs
   3 //
   4 // Authors:
   5 //   Dietmar Maurer (dietmar@ximian.com)
   6 //   Lluis Sanchez Gual (lluis@ideary.com)
   7 //   Patrik Torstensson
   8 //
   9 // (C) 2001 Ximian, Inc.  http://www.ximian.com
  10 //
  11
  12 using System;
  13 using System.Text;
  14 using System.Reflection;
  15 using System.Threading;
  16 using System.Collections;
  17 using System.Runtime.Remoting.Messaging;
  18 using System.Runtime.Remoting.Proxies;
  19 using System.Runtime.Remoting.Channels;
  20 using System.Runtime.Remoting.Contexts;
  21 using System.Runtime.Remoting.Activation;
  22 using System.Runtime.Remoting.Lifetime;
  23 using System.Runtime.CompilerServices;
  24 using System.Runtime.Serialization;
  25 using System.IO;
  26
  27 namespace System.Runtime.Remoting
  28 {
  29         public sealed class RemotingServices
  30         {
  31                 // Holds the identities of the objects, using uri as index
  32                 static Hashtable uri_hash = new Hashtable ();
  33
  34                 internal static string app_id;
  35                 static int next_id = 1;
  36
  37                 static RemotingServices ()
  38                 {
  39                         RegisterInternalChannels ();
  40                         app_id = Guid.NewGuid().ToString().Replace('-', '_') + "/";
  41                         CreateWellKnownServerIdentity (typeof(RemoteActivator), "RemoteActivationService.rem", WellKnownObjectMode.Singleton);
  42                 }
  43
  44                 private RemotingServices () {}
  45
  46                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  47                 internal extern static object InternalExecute (MonoMethod method, Object obj,
  48                                                                Object[] parameters, out object [] out_args);
  49
  50                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  51                 public extern static bool IsTransparentProxy (object proxy);
  52
  53                 internal static IMethodReturnMessage InternalExecuteMessage (
  54                         MarshalByRefObject target, IMethodCallMessage reqMsg)
  55                 {
  56                         ReturnMessage result;
  57
  58                         MonoMethod method = (MonoMethod) target.GetType().GetMethod(reqMsg.MethodName, BindingFlags.Public|BindingFlags.NonPublic|BindingFlags.Instance, null, (Type[]) reqMsg.MethodSignature, null);
  59                         object oldContext = CallContext.SetCurrentCallContext (reqMsg.LogicalCallContext);
  60
  61                         try
  62                         {
  63                                 object [] out_args;
  64                                 object rval = InternalExecute (method, target, reqMsg.Args, out out_args);
  65
  66                                 // Collect parameters with Out flag from the request message
  67
  68                                 ParameterInfo[] parameters = method.GetParameters();
  69                                 object[] returnArgs = new object [parameters.Length];
  70
  71                                 int n = 0;
  72                                 int noa = 0;
  73                                 foreach (ParameterInfo par in parameters)
  74                                 {
  75                                         if (par.IsOut && !par.ParameterType.IsByRef)
  76                                                 returnArgs [n++] = reqMsg.GetArg (par.Position);
  77                                         else if (par.ParameterType.IsByRef)
  78                                                 returnArgs [n++] = out_args [noa++];
  79                                 }
  80
  81                                 result = new ReturnMessage (rval, returnArgs, n, CallContext.CreateLogicalCallContext(), reqMsg);
  82                         }
  83                         catch (Exception e)
  84                         {
  85                                 result = new ReturnMessage (e, reqMsg);
  86                         }
  87
  88                         CallContext.RestoreCallContext (oldContext);
  89                         return result;
  90                 }
  91
  92                 public static IMethodReturnMessage ExecuteMessage (
  93                         MarshalByRefObject target, IMethodCallMessage reqMsg)
  94                 {
  95                         if (IsTransparentProxy(target))
  96                         {
  97                                 // Message must go through all chain of sinks
  98                                 RealProxy rp = GetRealProxy (target);
  99                                 return (IMethodReturnMessage) rp.Invoke (reqMsg);
 100                         }
 101                         else    // Direct call
 102                                 return InternalExecuteMessage (target, reqMsg);
 103                 }
 104
 105                 public static object Connect (Type classToProxy, string url)
 106                 {
 107                         ObjRef objRef = new ObjRef (classToProxy, url, null);
 108                         return GetRemoteObject (objRef, classToProxy);
 109                 }
 110
 111                 public static object Connect (Type classToProxy, string url, object data)
 112                 {
 113                         ObjRef objRef = new ObjRef (classToProxy, url, data);
 114                         return GetRemoteObject (objRef, classToProxy);
 115                 }
 116
 117                 public static bool Disconnect (MarshalByRefObject obj)
 118                 {
 119                         if (obj == null) throw new ArgumentNullException ("obj");
 120
 121                         ServerIdentity identity;
 122
 123                         if (IsTransparentProxy (obj))
 124                         {
 125                                 // CBOs are always accessed through a proxy, even in the server, so
 126                                 // for server CBOs it is ok to disconnect a proxy
 127
 128                                 RealProxy proxy = GetRealProxy(obj);
 129                                 if (proxy.GetProxiedType().IsContextful && (proxy.ObjectIdentity is ServerIdentity))
 130                                         identity = proxy.ObjectIdentity as ServerIdentity;
 131                                 else
 132                                         throw new ArgumentException ("The obj parameter is a proxy");
 133                         }
 134                         else
 135                                 identity = obj.ObjectIdentity;
 136
 137                         if (identity == null || !identity.IsConnected)
 138                                 return false;
 139                         else
 140                         {
 141                                 LifetimeServices.StopTrackingLifetime (identity);
 142                                 DisposeIdentity (identity);
 143                                 return true;
 144                         }
 145                 }
 146
 147                 public static Type GetServerTypeForUri (string uri)
 148                 {
 149                         Identity ident = GetIdentityForUri (uri);
 150                         if (ident == null) return null;
 151                         return ident.ObjectType;
 152                 }
 153
 154                 public static string GetObjectUri (MarshalByRefObject obj)
 155                 {
 156                         Identity ident = GetObjectIdentity(obj);
 157                         if (ident is ClientIdentity) return ((ClientIdentity)ident).TargetUri;
 158                         else if (ident != null) return ident.ObjectUri;
 159                         else return null;
 160                 }
 161
 162                 public static object Unmarshal (ObjRef objref)
 163                 {
 164                         return Unmarshal(objref, true);
 165                 }
 166
 167                 public static object Unmarshal (ObjRef objref, bool fRefine)
 168                 {
 169                         // FIXME: use type name when fRefine==true
 170
 171                         Type classToProxy = fRefine ? objref.ServerType : typeof (MarshalByRefObject);
 172                         if (classToProxy == null) classToProxy = typeof (MarshalByRefObject);
 173
 174                         if (objref.IsReferenceToWellKnow)
 175                                 return GetRemoteObject(objref, classToProxy);
 176                         else
 177                         {
 178                                 if (classToProxy.IsContextful)
 179                                 {
 180                                         // Look for a ProxyAttribute
 181                                         ProxyAttribute att = (ProxyAttribute) Attribute.GetCustomAttribute (classToProxy, typeof(ProxyAttribute),true);
 182                                         if (att != null)
 183                                                 return att.CreateProxy (objref, classToProxy, null, null).GetTransparentProxy();
 184                                 }
 185                                 return GetProxyForRemoteObject (objref, classToProxy);
 186                         }
 187                 }
 188
 189                 public static ObjRef Marshal (MarshalByRefObject obj)
 190                 {
 191                         return Marshal (obj, null, null);
 192                 }
 193
 194                 public static ObjRef Marshal (MarshalByRefObject obj, string uri)
 195                 {
 196                         return Marshal (obj, uri, null);
 197                 }
 198
 199                 public static ObjRef Marshal (MarshalByRefObject obj, string uri, Type requested_type)
 200                 {
 201                         if (IsTransparentProxy (obj))
 202                         {
 203                                 RealProxy proxy = RemotingServices.GetRealProxy(obj);
 204                                 Identity identity = proxy.ObjectIdentity;
 205
 206                                 if (identity != null)
 207                                 {
 208                                         if (identity.ObjectType.IsContextful && !identity.IsConnected)
 209                                         {
 210                                                 // Unregistered local contextbound object. Register now.
 211                                                 ClientActivatedIdentity cboundIdentity = (ClientActivatedIdentity)identity;
 212                                                 if (uri == null) uri = NewUri();
 213                                                 cboundIdentity.ObjectUri = uri;
 214                                                 RegisterServerIdentity (cboundIdentity);
 215                                                 cboundIdentity.StartTrackingLifetime ((ILease)obj.InitializeLifetimeService());
 216                                                 return cboundIdentity.CreateObjRef(requested_type);
 217                                         }
 218                                         else if (uri != null)
 219                                                 throw new RemotingException ("It is not possible marshal a proxy of a remote object");
 220
 221                                         return proxy.ObjectIdentity.CreateObjRef(requested_type);
 222                                 }
 223                         }
 224
 225                         if (requested_type == null) requested_type = obj.GetType();
 226
 227                         if (uri == null)
 228                         {
 229                                 uri = NewUri();
 230                                 CreateClientActivatedServerIdentity (obj, requested_type, uri);
 231                         }
 232                         else
 233                         {
 234                                 ClientActivatedIdentity identity = GetIdentityForUri ("/" + uri) as ClientActivatedIdentity;
 235                                 if (identity == null || obj != identity.GetServerObject())
 236                                         CreateClientActivatedServerIdentity (obj, requested_type, uri);
 237                         }
 238
 239                         return obj.CreateObjRef(requested_type);
 240                 }
 241
 242                 static string NewUri ()
 243                 {
 244                         return app_id + Environment.TickCount + "_" + next_id++;
 245                 }
 246
 247                 public static RealProxy GetRealProxy (object proxy)
 248                 {
 249                         if (!IsTransparentProxy(proxy)) throw new RemotingException("Cannot get the real proxy from an object that is not a transparent proxy");
 250                         return (RealProxy)((TransparentProxy)proxy)._rp;
 251                 }
 252
 253                 public static MethodBase GetMethodBaseFromMethodMessage(IMethodMessage msg)
 254                 {
 255                         Type type = Type.GetType (msg.TypeName);
 256                         if (type == null)
 257                                 throw new RemotingException ("Type '" + msg.TypeName + "' not found!");
 258
 259                         BindingFlags bflags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;
 260                         if (msg.MethodSignature == null)
 261                                 return type.GetMethod (msg.MethodName, bflags);
 262                         else
 263                                 return type.GetMethod (msg.MethodName, bflags, null, (Type[]) msg.MethodSignature, null);
 264                 }
 265
 266                 public static void GetObjectData(object obj, SerializationInfo info, StreamingContext context)
 267                 {
 268                         if (obj == null) throw new ArgumentNullException ("obj");
 269
 270                         ObjRef oref = Marshal ((MarshalByRefObject)obj);
 271                         oref.GetObjectData (info, context);
 272                 }
 273
 274                 public static ObjRef GetObjRefForProxy(MarshalByRefObject obj)
 275                 {
 276                         Identity ident = GetObjectIdentity(obj);
 277                         if (ident == null) return null;
 278                         else return ident.CreateObjRef(null);
 279                 }
 280
 281                 public static object GetLifetimeService (MarshalByRefObject obj)
 282                 {
 283                         if (obj == null) return null;
 284                         return obj.GetLifetimeService ();
 285                 }
 286
 287                 public static IMessageSink GetEnvoyChainForProxy (MarshalByRefObject obj)
 288                 {
 289                         if (IsTransparentProxy(obj))
 290                                 return ((ClientIdentity)GetRealProxy (obj).ObjectIdentity).EnvoySink;
 291                         else
 292                                 throw new ArgumentException ("obj must be a proxy","obj");
 293                 }
 294
 295                 public static void LogRemotingStage (int stage)
 296                 {
 297                         throw new NotImplementedException ();
 298                 }
 299
 300                 [MonoTODO]
 301                 public static string GetSessionIdForMethodMessage(IMethodMessage msg)
 302                 {
 303                         throw new NotImplementedException ();
 304                 }
 305
 306                 public static bool IsMethodOverloaded(IMethodMessage msg)
 307                 {
 308                         Type type = msg.MethodBase.DeclaringType;
 309                         MemberInfo[] members = type.GetMember (msg.MethodName, MemberTypes.Method, BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
 310                         return members.Length > 1;
 311                 }
 312
 313                 public static bool IsObjectOutOfAppDomain(object tp)
 314                 {
 315                         Identity ident = GetObjectIdentity((MarshalByRefObject)tp);
 316                         if (ident != null) return !ident.IsFromThisAppDomain;
 317                         else return false;
 318                 }
 319
 320                 public static bool IsObjectOutOfContext(object tp)
 321                 {
 322                         ServerIdentity ident = GetObjectIdentity((MarshalByRefObject)tp) as ServerIdentity;
 323                         if (ident != null) return ident.Context != System.Threading.Thread.CurrentContext;
 324                         else return false;
 325                 }
 326
 327                 public static bool IsOneWay(MethodBase method)
 328                 {
 329                         // TODO: use internal call for better performance
 330                         object[] atts = method.GetCustomAttributes (typeof (OneWayAttribute), false);
 331                         return atts.Length > 0;
 332                 }
 333
 334                 public static bool IsAsyncMessage(IMessage msg)
 335                 {
 336                         if (! (msg is MonoMethodMessage)) return false;
 337                         else if (((MonoMethodMessage)msg).IsAsync) return true;
 338                         else if (IsOneWay (((MonoMethodMessage)msg).MethodBase)) return true;
 339                         else return false;
 340                 }
 341
 342                 public static void SetObjectUriForMarshal(MarshalByRefObject obj, string uri)
 343                 {
 344                         if (IsTransparentProxy (obj)) throw new RemotingException ("SetObjectUriForMarshal method should only be called for MarshalByRefObjects that exist in the current AppDomain.");
 345                         Marshal (obj, uri);
 346                 }
 347
 348                 #region Internal Methods
 349
 350                 internal static object CreateClientProxy (ActivatedClientTypeEntry entry, object[] activationAttributes)
 351                 {
 352                         if (entry.ContextAttributes != null || activationAttributes != null)
 353                         {
 354                                 ArrayList props = new ArrayList ();
 355                                 if (entry.ContextAttributes != null) props.AddRange (entry.ContextAttributes);
 356                                 if (activationAttributes != null) props.AddRange (activationAttributes);
 357                                 return CreateClientProxy (entry.ObjectType, entry.ApplicationUrl, props.ToArray ());
 358                         }
 359                         else
 360                                 return CreateClientProxy (entry.ObjectType, entry.ApplicationUrl, null);
 361                 }
 362
 363                 internal static object CreateClientProxy (Type objectType, string url, object[] activationAttributes)
 364                 {
 365                         string activationUrl = url + "/RemoteActivationService.rem";
 366
 367                         string objectUri;
 368                         IMessageSink sink = GetClientChannelSinkChain (activationUrl, null, out objectUri);
 369
 370                         RemotingProxy proxy = new RemotingProxy (objectType, activationUrl, activationAttributes);
 371                         return proxy.GetTransparentProxy();
 372                 }
 373
 374                 internal static object CreateClientProxy (WellKnownClientTypeEntry entry)
 375                 {
 376                         return Connect (entry.ObjectType, entry.ObjectUrl, null);
 377                 }
 378
 379                 internal static object CreateClientProxyForContextBound (Type type, object[] activationAttributes)
 380                 {
 381                         if (type.IsContextful)
 382                         {
 383                                 // Look for a ProxyAttribute
 384                                 ProxyAttribute att = (ProxyAttribute) Attribute.GetCustomAttribute (type, typeof(ProxyAttribute), true);
 385                                 if (att != null)
 386                                         return att.CreateInstance (type);
 387                         }
 388                         RemotingProxy proxy = new RemotingProxy (type, ChannelServices.CrossContextUrl, activationAttributes);
 389                         return proxy.GetTransparentProxy();
 390                 }
 391
 392                 internal static Identity GetIdentityForUri (string uri)
 393                 {
 394                         lock (uri_hash)
 395                         {
 396                                 return (Identity)uri_hash [GetNormalizedUri(uri)];
 397                         }
 398                 }
 399
 400                 internal static Identity GetObjectIdentity (MarshalByRefObject obj)
 401                 {
 402                         if (IsTransparentProxy(obj))
 403                                 return GetRealProxy (obj).ObjectIdentity;
 404                         else
 405                                 return obj.ObjectIdentity;
 406                 }
 407
 408                 internal static ClientIdentity GetOrCreateClientIdentity(ObjRef objRef, Type proxyType, out object clientProxy)
 409                 {
 410                         // This method looks for an identity for the given url.
 411                         // If an identity is not found, it creates the identity and
 412                         // assigns it a proxy to the remote object.
 413
 414                         // Creates the client sink chain for the given url or channelData.
 415                         // It will also get the object uri from the url.
 416
 417                         object channelData = objRef.ChannelInfo != null ? objRef.ChannelInfo.ChannelData : null;
 418                         string url = (channelData == null) ? objRef.URI : null;
 419
 420                         string objectUri;
 421                         IMessageSink sink = GetClientChannelSinkChain (url, channelData, out objectUri);
 422
 423                         if (objectUri == null) objectUri = objRef.URI;
 424
 425                         lock (uri_hash)
 426                         {
 427                                 clientProxy = null;
 428                                 string uri = GetNormalizedUri (objRef.URI);
 429
 430                                 ClientIdentity identity = uri_hash [uri] as ClientIdentity;
 431                                 if (identity != null)
 432                                 {
 433                                         // Object already registered
 434                                         clientProxy = identity.ClientProxy;
 435                                         if (clientProxy != null) return identity;
 436
 437                                         // The proxy has just been GCed, so its identity cannot
 438                                         // be reused. Just dispose it.
 439                                         DisposeIdentity (identity);
 440                                 }
 441
 442                                 // Creates an identity and a proxy for the remote object
 443
 444                                 identity = new ClientIdentity (objectUri, objRef);
 445                                 identity.ChannelSink = sink;
 446
 447                                 // Registers the identity
 448                                 uri_hash [uri] = identity;
 449
 450                                 if (proxyType != null)
 451                                 {
 452                                         RemotingProxy proxy = new RemotingProxy (proxyType, identity);
 453                                         clientProxy = proxy.GetTransparentProxy();
 454                                         identity.ClientProxy = (MarshalByRefObject) clientProxy;
 455                                 }
 456
 457                                 return identity;
 458                         }
 459                 }
 460
 461                 static IMessageSink GetClientChannelSinkChain(string url, object channelData, out string objectUri)
 462                 {
 463                         IMessageSink sink = ChannelServices.CreateClientChannelSinkChain (url, channelData, out objectUri);
 464                         if (sink == null)
 465                         {
 466                                 if (url != null)
 467                                 {
 468                                         string msg = String.Format ("Cannot create channel sink to connect to URL {0}. An appropriate channel has probably not been registered.", url);
 469                                         throw new RemotingException (msg);
 470                                 }
 471                                 else
 472                                 {
 473                                         string msg = String.Format ("Cannot create channel sink to connect to the remote object. An appropriate channel has probably not been registered.", url);
 474                                         throw new RemotingException (msg);
 475                                 }
 476                         }
 477                         return sink;
 478                 }
 479
 480                 internal static ClientActivatedIdentity CreateContextBoundObjectIdentity(Type objectType)
 481                 {
 482                         ClientActivatedIdentity identity = new ClientActivatedIdentity (null, objectType);
 483                         identity.ChannelSink = ChannelServices.CrossContextChannel;
 484                         return identity;
 485                 }
 486
 487                 internal static ClientActivatedIdentity CreateClientActivatedServerIdentity(MarshalByRefObject realObject, Type objectType, string objectUri)
 488                 {
 489                         ClientActivatedIdentity identity = new ClientActivatedIdentity (objectUri, objectType);
 490                         identity.AttachServerObject (realObject, Context.DefaultContext);
 491                         RegisterServerIdentity (identity);
 492                         identity.StartTrackingLifetime ((ILease)realObject.InitializeLifetimeService ());
 493                         return identity;
 494                 }
 495
 496                 internal static ServerIdentity CreateWellKnownServerIdentity(Type objectType, string objectUri, WellKnownObjectMode mode)
 497                 {
 498                         ServerIdentity identity;
 499
 500                         if (mode == WellKnownObjectMode.SingleCall)
 501                                 identity = new  SingleCallIdentity(objectUri, Context.DefaultContext, objectType);
 502                         else
 503                                 identity = new  SingletonIdentity(objectUri, Context.DefaultContext, objectType);
 504
 505                         RegisterServerIdentity (identity);
 506                         return identity;
 507                 }
 508
 509                 private static void RegisterServerIdentity(ServerIdentity identity)
 510                 {
 511                         lock (uri_hash)
 512                         {
 513                                 if (uri_hash.ContainsKey (identity.ObjectUri))
 514                                         throw new RemotingException ("Uri already in use: " + identity.ObjectUri);
 515
 516                                 uri_hash[identity.ObjectUri] = identity;
 517                         }
 518                 }
 519
 520                 internal static object GetProxyForRemoteObject (ObjRef objref, Type classToProxy)
 521                 {
 522                         ClientActivatedIdentity identity = GetIdentityForUri (objref.URI) as ClientActivatedIdentity;
 523                         if (identity != null) return identity.GetServerObject ();
 524                         else return GetRemoteObject (objref, classToProxy);
 525                 }
 526
 527                 internal static object GetRemoteObject(ObjRef objRef, Type proxyType)
 528                 {
 529                         object proxy;
 530                         GetOrCreateClientIdentity (objRef, proxyType, out proxy);
 531                         return proxy;
 532                 }
 533
 534                 internal static object GetDomainProxy(AppDomain domain)
 535                 {
 536                         byte[] data = null;
 537
 538                         Context currentContext = Thread.CurrentContext;
 539                         AppDomain currentDomain = AppDomain.InternalSetDomain (domain);
 540                         try
 541                         {
 542                                 data = domain.GetMarshalledDomainObjRef ();
 543                         }
 544                         finally
 545                         {
 546                                 AppDomain.InternalSetDomain (currentDomain);
 547                                 AppDomain.InternalSetContext (currentContext);
 548                         }
 549
 550                         MemoryStream stream = new MemoryStream (data);
 551                         ObjRef appref = (ObjRef) CADSerializer.DeserializeObject (stream);
 552                         return (AppDomain) RemotingServices.Unmarshal(appref);
 553                 }
 554
 555                 private static void RegisterInternalChannels()
 556                 {
 557                         CrossAppDomainChannel.RegisterCrossAppDomainChannel();
 558                 }
 559
 560                 internal static void DisposeIdentity (Identity ident)
 561                 {
 562                         lock (uri_hash)
 563                         {
 564                                 if (!ident.Disposed) {
 565                                         uri_hash.Remove (ident.ObjectUri);
 566                                         ident.Disposed = true;
 567                                 }
 568                         }
 569                 }
 570
 571                 internal static Identity GetMessageTargetIdentity (IMessage msg)
 572                 {
 573                         // Returns the identity where the message is sent
 574
 575                         if (msg is IInternalMessage)
 576                                 return ((IInternalMessage)msg).TargetIdentity;
 577
 578                         lock (uri_hash)
 579                         {
 580                                 string uri = GetNormalizedUri (((IMethodMessage)msg).Uri);
 581                                 return uri_hash [uri] as ServerIdentity;
 582                         }
 583                 }
 584
 585                 internal static void SetMessageTargetIdentity (IMessage msg, Identity ident)
 586                 {
 587                         if (msg is IInternalMessage)
 588                                 ((IInternalMessage)msg).TargetIdentity = ident;
 589                 }
 590
 591                 internal static bool UpdateOutArgObject (ParameterInfo pi, object local, object remote)
 592                 {
 593                         if (local is StringBuilder)
 594                         {
 595                                 StringBuilder sb = local as StringBuilder;
 596                                 sb.Remove (0, sb.Length);
 597                                 sb.Append (remote.ToString());
 598                                 return true;
 599                         }
 600                         else if (pi.ParameterType.IsArray && ((Array)local).Rank == 1)
 601                         {
 602                                 Array alocal = (Array) local;
 603                                 if (alocal.Rank == 1)
 604                                 {
 605                                         Array.Copy ((Array) remote, alocal, alocal.Length);
 606                                         return true;
 607                                 }
 608                                 else
 609                                 {
 610                                         // TODO
 611                                 }
 612                         }
 613                         return false;
 614                 }
 615
 616                 static string GetNormalizedUri (string uri)
 617                 {
 618                         if (uri.StartsWith ("/")) return uri.Substring (1);
 619                         else return uri;
 620                 }
 621
 622                 #endregion
 623         }
 624 }