我遇到了客户端无法在第二次启动时注册回调通道的问题。我尝试了各种事情，似乎我找到了一种解决方案，可以在服务关闭时删除 Close(( 通道(包装器中的 ResetProxy(( 调用(调用。但事实证明，这导致了另一个问题：服务器崩溃并出现错误"线程试图读取或写入它没有适当访问权限的虚拟地址"。此外，还有一些与网络相关的问题也会导致相同的行为。解决方案始终是重新启动服务器，这不是修复回调通道注册的正确选项。 谁能提出可能是什么问题？我做了很多测试，似乎这与所有客户端的突然停止(多个服务的全局停止(以及服务的数量也很重要有关。因此，在服务器重新启动之前，即使是新客户端也无法向服务器注册。这听起来像是服务器正在阻止关闭的频道。
合同：
[ServiceContract(SessionMode = SessionMode.Required, CallbackContract = typeof(IAgentCallback))]
public interface IAgentManager
{
[OperationContract]
string RegisterAgent(string hostName);
[OperationContract]
bool Ping();
}
客户端创建回调代码(截断(：
public class AgentCallbackDaemon
{
private void CreateManagerProxy()
{
Reset();
var isUnbound = true;
while (isUnbound)
{
try
{
ManagerProxy = new ProxyWrapper<AgentManagerProxy, IAgentManager>(CreateProxy);
ManagerProxy.ChannelStateChanged += HandleProxyConnectionStateChanged;
isUnbound = false;
}
catch (AddressAlreadyInUseException)
{
sLog.ErrorFormat("Port is already reserved, binding failed.");
}
catch (Exception error)
{
sLog.ErrorFormat($"No proxy due to {error}");
throw;
}
}
}
private AgentManagerProxy CreateProxy()
=> mCallbackChannelPortRange.IsCallbackPortRageSet() ? GetProxyWithPortRange() : GetProxyDefault();
private AgentManagerProxy GetProxyDefault()
=> new AgentManagerProxy(mAgentCallback, mManagerUri, GetServiceName());
private AgentManagerProxy GetProxyWithPortRange()
{
var minPort = mCallbackChannelPortRange.MinimumCallbackPortNumber;
var maxPort = mCallbackChannelPortRange.MaximumCallbackPortNumber;
return new AgentManagerProxy(mAgentCallback, mManagerUri, GetServiceName(), minPort, maxPort);
}
}
客户端回调代码(截断(：
public class AgentManagerProxy : DuplexClientBase<IAgentManager>, IAgentManager
{
public const string SERVICE_NAME = "AgentManager";
public AgentManagerProxy(IAgentCallback callback, string serviceAddress, string connectionId,
ushort minPort, ushort maxPort)
: base(callback, BindingAbstractFactory.DuplexServiceClientBindingFactory(connectionId,
minPort, maxPort), BindingUtility.CreateEndpoint(serviceAddress, SERVICE_NAME))
{
}
public string RegisterAgent(string hostName)
=> Channel.RegisterAgent(hostName);
public bool Ping() => return Channel.Ping();
}
public static class BindingAbstractFactory
{
public static Binding DuplexServiceClientBindingFactory(string connectionId, ushort minPort, ushort maxPort)
=> CreateDuplexServiceClientBinding(connectionId, minPort, maxPort);
private static Binding CreateDuplexServiceClientBinding(string connectionId, ushort minPort, ushort maxPort)
{
var binding = CreateDuplexServiceHostBinding();
if (binding is WSDualHttpBinding)
{
lock (sLock)
{
try
{
((WSDualHttpBinding)binding).ClientBaseAddress =
CreateClientBaseAddress(connectionId, minPort, maxPort);
}
catch (Exception error)
{
sLog.ErrorFormat("Unexpected exception: {0}", error);
throw error;
}
finally
{
Monitor.PulseAll(sLock);
}
}
}
return binding;
}
private static Binding CreateDuplexServiceHostBinding()
{
var binding = new WSDualHttpBinding
{
ReceiveTimeout = TimeSpan.MaxValue,
MaxReceivedMessageSize = int.MaxValue,
ReaderQuotas =
{
// Set the maximum sizes to allow big message sizes.
MaxArrayLength = int.MaxValue,
MaxBytesPerRead = int.MaxValue,
MaxDepth = int.MaxValue,
MaxNameTableCharCount = int.MaxValue,
MaxStringContentLength = int.MaxValue
},
Security =
{
// Disable security on control services.
// TODO: Once security concept has been clarified, update this to reflect security rules.
Mode = WSDualHttpSecurityMode.None,
Message = { ClientCredentialType = MessageCredentialType.None }
//// binding.Security.Mode = SecurityMode.None;
//// binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.None;
}
};
return binding;
}
private static Uri CreateClientBaseAddress(string connectionId, ushort minPort, ushort maxPort)
{
var fullDnsName = Dns.GetHostEntry(Dns.GetHostName()).HostName;
int portNumber;
if (maxPort == ushort.MaxValue)
portNumber = LocalPorts.GetRandomAvailablePort(connectionId, minPort, maxPort);
else
portNumber = LocalPorts.GetNextAvailablePort(connectionId, minPort, maxPort);
return new Uri($@"http://{fullDnsName}:{portNumber}");
}
}
所有这些都包装到带有重置功能的代理包装器中，该功能在服务停止或任何错误(包括网络(时调用：
public class ProxyWrapper<TPROXY, TSERVICE> where TPROXY : ClientBase<TSERVICE> where TSERVICE : class
{
public delegate TPROXY CreateProxy();
private readonly object mProxyLock = new object();</summary>
private readonly CreateProxy mCreateProxy;
private TPROXY mProxy;
public ProxyWrapper(CreateProxy createProxyCallback)
{
mLog.Info.Write($"Creating Proxy for '{typeof(TPROXY).FullName}'");
mCreateProxy = createProxyCallback;
BuildProxy();
}
public event EventHandler<CommunicationState> ChannelStateChanged;
public TPROXY Proxy
{
get
{
lock (mProxyLock)
{
if (mProxy == null)
BuildProxy();
return mProxy;
}
}
}
public void ResetProxy()
{
mLog.Info.Write("Call ResetProxy()");
lock (mProxyLock)
{
try
{
if (mProxy == null)
return;
UnSubscribeFromChannelEvents();
CloseProxy();
}
catch (Exception ex)
{
// Catch all exceptions, and ignore them.
}
finally
{
mProxy = null;
}
}
}
private void RaiseChannelStateChanged(object sender, EventArgs e)
=> ChannelStateChanged?.Invoke(this, mProxy.InnerChannel.State);
private void RaiseChannelEnteredFaultyState()
=> ChannelStateChanged?.Invoke(this, CommunicationState.Faulted);
private void BuildProxy()
{
lock (mProxyLock)
{
if (mProxy != null)
ResetProxy();
mProxy = mCreateProxy();
SubscribeToChannelEvents();
}
}
private void SubscribeToChannelEvents()
{
if (mProxy?.InnerChannel == null)
return;
mProxy.InnerChannel.Faulted += OnInnerChannelFaulted;
mProxy.InnerChannel.Closed += RaiseChannelStateChanged;
mProxy.InnerChannel.Closing += RaiseChannelStateChanged;
mProxy.InnerChannel.Opened += RaiseChannelStateChanged;
mProxy.InnerChannel.Opening += RaiseChannelStateChanged;
}
private void UnSubscribeFromChannelEvents()
{
if (mProxy?.InnerChannel == null)
return;
mProxy.InnerChannel.Faulted -= OnInnerChannelFaulted;
mProxy.InnerChannel.Closed -= RaiseChannelStateChanged;
mProxy.InnerChannel.Closing -= RaiseChannelStateChanged;
mProxy.InnerChannel.Opened -= RaiseChannelStateChanged;
mProxy.InnerChannel.Opening -= RaiseChannelStateChanged;
}
private void OnInnerChannelFaulted(object sender, EventArgs e)
{
ResetProxy();
RaiseChannelEnteredFaultyState();
}
private void CloseProxy()
{
try
{
mProxy.Close();
}
catch (Exception ex)
{
try
{
mProxy.Abort();
}
catch (Exception abortException) { // ignored }
}
try
{
mProxy.ChannelFactory.Close();
}
catch (Exception ex)
{
try
{
mProxy.ChannelFactory.Abort();
}
catch (Exception abortException) { // ignored }
}
}
}
服务器仅维护回调列表。
- 为"代理管理器代理"创建代理
- 调用 BuildProxy((
- mProxy.Open(( [State=Created]
- 调用订阅频道事件(( ......
- .........
- 服务停止...
- 调用重置代理((
- 调用取消订阅来自频道事件(( 调用 CloseProxy(
- (： mProxy.Close(( 调用 CloseProxy(
- (： mProxy.ChannelFactory.Close((
为客户端添加的日志记录在首次启动时显示以下内容：
第二次启动时，服务失败：
- 为"代理管理器代理"创建代理
- 调用 BuildProxy((
- mProxy.Open(( [State=Created]
错误：由于系统而没有代理。超时异常：请求通道在 00：00：00 之后尝试发送超时。增加传递给请求调用的超时值，或增加绑定上的 SendTimeout 值。分配给此操作的时间可能是较长超时的一部分。---> System.TimeoutException：对"http://xxxxx:9003/AgentManager"的 HTTP 请求已超过分配的超时 00：00：00。分配给此操作的时间可能是较长超时的一部分。 at System.ServiceModel.Channels.HttpChannelUtilities.SetRequestTimeout(HttpWebRequest request， TimeSpan timeout( at System.ServiceModel.Channels.HttpChannelFactory'1.HttpRequestChannel.HttpChannelRequest.SendRequest(Message message， TimeSpan timeout( at System.ServiceModel.Channels.RequestChannel.Request(Message message， TimeSpan timeout( ---内部异常堆栈跟踪结束---
客户端的数量可能会超过 Maxconcurrentinstances 的值。 Maxconcurrentinstances 是一个正整数，用于限制一次可以通过 ServiceHost 执行的实例上下文对象的数量。当槽数低于限制时，创建其他实例的请求将排队并完成。默认值是最大并发会话数和最大并发调用数的总和。您需要在每个客户端完成后关闭通道。否则，客户端长时间排队后会出现异常。
try
{
if (client.State != System.ServiceModel.CommunicationState.Faulted)
{
client.Close();
}
}
catch (Exception ex)
{
client.Abort();
}
关闭方法可能会失败。如果关闭方法失败，则需要中止方法。