注册表扫描类型的结构映射拦截
本文关键字:映射 结构 扫描 类型 注册表 | 更新日期: 2023-09-27 18:25:18
我有一个使用Structuremap的ASP MVC 4应用程序。我正试图通过Structuremap拦截将日志记录添加到我的应用程序中。在注册表中,我扫描一个特定的程序集,以便使用默认约定注册它的所有类型:
public class ServicesRegistry : Registry
{
public ServicesRegistry()
{
Scan(x =>
{
x.AssemblyContainingType<MyMarkerService>();
x.WithDefaultConventions();
});
}
}
拦截器:
public class LogInterceptor : IInterceptor
{
public void Intercept(IInvocation invocation)
{
var watch = Stopwatch.StartNew();
invocation.Proceed();
watch.Stop();//log the time
}
}
我可以为一种特定的插件类型添加拦截器,如下所示:
var proxyGenerator = new ProxyGenerator();
container.Configure(x => x.For<IServiceA>().Use<ServiceA>().DecorateWith(instance => proxyGenerator.CreateInterfaceProxyWithTarget(instance, new LogInterceptor())));
但我想让structuremap为注册表中扫描的所有类型创建日志代理。有办法做到这一点吗?
这似乎没有一个简单的扩展点,但我使用自定义约定使用了一个相当不错的解决方案。为了帮助你理解我所做的决定,我将带你走几个步骤(跳过我在路上犯的很多错误)。
首先我们来看一下您已经在使用的DefaultConvention。
违约公约:
public class DefaultConventionScanner : ConfigurableRegistrationConvention
{
public override void Process(Type type, Registry registry)
{
if (!TypeExtensions.IsConcrete(type))
return;
Type pluginType = this.FindPluginType(type);
if (pluginType == null || !TypeExtensions.HasConstructors(type))
return;
registry.AddType(pluginType, type);
this.ConfigureFamily(registry.For(pluginType, (ILifecycle)null));
}
public virtual Type FindPluginType(Type concreteType)
{
string interfaceName = "I" + concreteType.Name;
return Enumerable.FirstOrDefault<Type>((IEnumerable<Type>)concreteType.GetInterfaces(), (Func<Type, bool>)(t => t.Name == interfaceName));
}
}
非常简单,我们获取类型和接口对,并检查以确保它们有构造函数,如果有,我们将注册它们。如果只修改它,使其调用DecorateWith,那就太好了,但您只能在For<>上调用它()。使用<>(),而不是For().Use().
接下来让我们看看DecorateWith的作用:
public T DecorateWith(Expression<Func<TPluginType, TPluginType>> handler)
{
this.AddInterceptor((IInterceptor) new FuncInterceptor<TPluginType>(handler, (string) null));
return this.thisInstance;
}
因此,这创建了一个FuncInterceptor并将其注册。我花了相当多的时间试图通过反射动态创建其中一个,然后才决定创建一个新类会更容易:
public class ProxyFuncInterceptor<T> : FuncInterceptor<T> where T : class
{
public ProxyFuncInterceptor() : base(x => MakeProxy(x), "")
{
}
protected ProxyFuncInterceptor(Expression<Func<T, T>> expression, string description = null)
: base(expression, description)
{
}
protected ProxyFuncInterceptor(Expression<Func<IContext, T, T>> expression, string description = null)
: base(expression, description)
{
}
private static T MakeProxy(T instance)
{
var proxyGenerator = new ProxyGenerator();
return proxyGenerator.CreateInterfaceProxyWithTarget(instance, new LogInterceptor());
}
}
当我们将类型作为变量时,这个类只会使它更容易使用。
最后,我在默认约定的基础上制定了自己的约定。
public class DefaultConventionWithProxyScanner : ConfigurableRegistrationConvention
{
public override void Process(Type type, Registry registry)
{
if (!type.IsConcrete())
return;
var pluginType = this.FindPluginType(type);
if (pluginType == null || !type.HasConstructors())
return;
registry.AddType(pluginType, type);
var policy = CreatePolicy(pluginType);
registry.Policies.Interceptors(policy);
ConfigureFamily(registry.For(pluginType));
}
public virtual Type FindPluginType(Type concreteType)
{
var interfaceName = "I" + concreteType.Name;
return concreteType.GetInterfaces().FirstOrDefault(t => t.Name == interfaceName);
}
public IInterceptorPolicy CreatePolicy(Type pluginType)
{
var genericPolicyType = typeof(InterceptorPolicy<>);
var policyType = genericPolicyType.MakeGenericType(pluginType);
return (IInterceptorPolicy)Activator.CreateInstance(policyType, new object[]{CreateInterceptor(pluginType), null});
}
public IInterceptor CreateInterceptor(Type pluginType)
{
var genericInterceptorType = typeof(ProxyFuncInterceptor<>);
var specificInterceptor = genericInterceptorType.MakeGenericType(pluginType);
return (IInterceptor)Activator.CreateInstance(specificInterceptor);
}
}
这几乎完全相同。另外,我为我们注册的每个类型创建了一个拦截器和拦截器类型。然后我注册该政策。
最后,通过一些单元测试来证明它是有效的:
[TestFixture]
public class Try4
{
[Test]
public void Can_create_interceptor()
{
var type = typeof (IServiceA);
Assert.NotNull(new DefaultConventionWithProxyScanner().CreateInterceptor(type));
}
[Test]
public void Can_create_policy()
{
var type = typeof (IServiceA);
Assert.NotNull(new DefaultConventionWithProxyScanner().CreatePolicy(type));
}
[Test]
public void Can_register_normally()
{
var container = new Container();
container.Configure(x => x.Scan(y =>
{
y.TheCallingAssembly();
y.WithDefaultConventions();
}));
var serviceA = container.GetInstance<IServiceA>();
Assert.IsFalse(ProxyUtil.IsProxy(serviceA));
Console.WriteLine(serviceA.GetType());
}
[Test]
public void Can_register_proxy_for_all()
{
var container = new Container();
container.Configure(x => x.Scan(y =>
{
y.TheCallingAssembly();
y.Convention<DefaultConventionWithProxyScanner>();
}));
var serviceA = container.GetInstance<IServiceA>();
Assert.IsTrue(ProxyUtil.IsProxy(serviceA));
Console.WriteLine(serviceA.GetType());
}
[Test]
public void Make_sure_I_wait()
{
var container = new Container();
container.Configure(x => x.Scan(y =>
{
y.TheCallingAssembly();
y.Convention<DefaultConventionWithProxyScanner>();
}));
var serviceA = container.GetInstance<IServiceA>();
serviceA.Wait();
}
}
}
public interface IServiceA
{
void Wait();
}
public class ServiceA : IServiceA
{
public void Wait()
{
Thread.Sleep(1000);
}
}
public interface IServiceB
{
}
public class ServiceB : IServiceB
{
}
这里肯定有一些清理的空间(缓存,使其干燥,更多的测试,使其更容易配置),但它可以满足您的需求,并且是一种非常合理的方法
请询问您是否还有其他问题。