【ABP框架系列学习】介绍篇(1)

时间 2019-11-05

标签 ABP框架系列学习介绍繁體版

原文原文链接

0.引言

该系列博文主要在【官方文档】及【tkbSimplest】ABP框架理论研究系列博文的基础上进行总结的，或许你们会质问，别人都已经翻译过了，这不是画蛇添足吗？缘由以下：javascript

1.【tkbSimplest】的相关博文因为撰写得比较早的，在参照官方文档学习的过程当中，发现部分知识未能及时同步(当前V4.0.2版本)，如【EntityHistory】、【Multi-Lingual Engities】章节未涉及、【Caching】章节没有Entity Caching等内容。html

2.进一步深刻学习ABP的理论知识。java

3.借此机会提升英文文档的阅读能力，故根据官方当前最新的版本，并在前人的基础上，本身也感觉一下英文帮助文档的魅力。git

好了，下面开始进入正题。github

1.APB是什么？

ABP是ASP.NET Boilerplate的简称，从英文字面上理解它是一个关于ASP.NET的模板，在github上已经有5.7k的star(截止2018年11月21日)。官方的解释：ABP是一个开源且文档友好的应用程序框架。ABP不只仅是一个框架，它还提供了一个最徍实践的基于领域驱动设计(DDD)的体系结构模型。ajax

ABP与最新的ASP.NET CORE和EF CORE版本保持同步，一样也支持ASP.NET MVC 5.x和EF6.x。json

2.一个快速事例

让咱们研究一个简单的类，看看ABP具备哪些优势：浏览器

public class TaskAppService : ApplicationService, ITaskAppService
    {
        private readonly IRepository<Task> _taskRepository;

        public TaskAppService(IRepository<Task> taskRepository)
        {
            _taskRepository = taskRepository;
        }

        [AbpAuthorize(MyPermissions.UpdateTasks)]
        public async Task UpdateTask(UpdateTaskInput input)
        {
            Logger.Info("Updating a task for input: " + input);

            var task = await _taskRepository.FirstOrDefaultAsync(input.TaskId);
            if (task == null)
            {
                throw new UserFriendlyException(L("CouldNotFindTheTaskMessage"));
            }

            input.MapTo(task);
        }
    }

这里咱们看到一个Application Service(应用服务)方法。在DDD中，应用服务直接用于表现层(UI)执行应用程序的用例。那么在UI层中就能够经过javascript ajax的方式调用UpdateTask方法。缓存

var _taskService = abp.services.app.task;
_taskService.updateTask(...);

3.ABP的优势

经过上述事例，让咱们来看看ABP的一些优势：app

依赖注入（Dependency Injection）：ABP使用并提供了传统的DI基础设施。上述TaskAppService类是一个应用服务(继承自ApplicationService)，因此它按照惯例以短暂(每次请求建立一次)的形式自动注册到DI容器中。一样的，也能够简单地注入其余依赖(如事例中的IRepository<Task>)。

部分源码分析：TaskAppService类继承自ApplicationService，IApplicaitonServcie又继承自ITransientDependency接口，在ABP框架中已经将ITransientDependency接口注入到DI容器中，全部继承自ITransientDependency接口的类或接口都会默认注入。

 //空接口
  public interface ITransientDependency
  {

  }
   
  //应用服务接口
  public interface IApplicationService : ITransientDependency
  {

  }

  //仓储接口
  public interface IRepository : ITransientDependency
  {
        
  }

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 public class BasicConventionalRegistrar : IConventionalDependencyRegistrar
    {
        public void RegisterAssembly(IConventionalRegistrationContext context)
        {
            //注入到IOC，全部继承自ITransientDependency的类、接口等都会默认注入
            context.IocManager.IocContainer.Register(
                Classes.FromAssembly(context.Assembly)
                    .IncludeNonPublicTypes()
                    .BasedOn<ITransientDependency>()
                    .If(type => !type.GetTypeInfo().IsGenericTypeDefinition)
                    .WithService.Self()
                    .WithService.DefaultInterfaces()
                    .LifestyleTransient()
                );

            //Singleton
            context.IocManager.IocContainer.Register(
                Classes.FromAssembly(context.Assembly)
                    .IncludeNonPublicTypes()
                    .BasedOn<ISingletonDependency>()
                    .If(type => !type.GetTypeInfo().IsGenericTypeDefinition)
                    .WithService.Self()
                    .WithService.DefaultInterfaces()
                    .LifestyleSingleton()
                );

            //Windsor Interceptors
            context.IocManager.IocContainer.Register(
                Classes.FromAssembly(context.Assembly)
                    .IncludeNonPublicTypes()
                    .BasedOn<IInterceptor>()
                    .If(type => !type.GetTypeInfo().IsGenericTypeDefinition)
                    .WithService.Self()
                    .LifestyleTransient()
                );
        }

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仓储(Repository)：ABP能够为每个实体建立一个默认的仓储(如事例中的IRepository<Task>)。默认的仓储提供了不少有用的方法，如事例中的FirstOrDefault方法。固然，也能够根据需求扩展默认的仓储。仓储抽象了DBMS和ORMs，并简化了数据访问逻辑。

受权(Authorization)：ABP能够经过声明的方式检查权限。若是当前用户没有【update task】的权限或没有登陆，则会阻止访问UpdateTask方法。ABP不只提供了声明属性的方式受权，并且还能够经过其它的方式。

部分源码分析：AbpAuthorizeAttribute类实现了Attribute，可在类或方法上经过【AbpAuthorize】声明。

   [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true)]
   public class AbpAuthorizeAttribute : Attribute, IAbpAuthorizeAttribute
   {
        /// <summary>
        /// A list of permissions to authorize.
        /// </summary>
        public string[] Permissions { get; }

        /// <summary>
        /// If this property is set to true, all of the <see cref="Permissions"/> must be 
            granted.
        /// If it's false, at least one of the <see cref="Permissions"/> must be granted.
        /// Default: false.
        /// </summary>
        public bool RequireAllPermissions { get; set; }

        /// <summary>
        /// Creates a new instance of <see cref="AbpAuthorizeAttribute"/> class.
        /// </summary>
        /// <param name="permissions">A list of permissions to authorize</param>
        public AbpAuthorizeAttribute(params string[] permissions)
        {
            Permissions = permissions;
        }
    }

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经过AuthorizationProvider类中的SetPermissions方法进行自定义受权。

 public abstract class AuthorizationProvider : ITransientDependency
    {
        /// <summary>
        /// This method is called once on application startup to allow to define 
            permissions.
        /// </summary>
        /// <param name="context">Permission definition context</param>
        public abstract void SetPermissions(IPermissionDefinitionContext context);
    }

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验证(Validation)：ABP自动检查输入是否为null。它也基于标准数据注释特性和自定义验证规则验证全部的输入属性。若是请求无效，它会在客户端抛出适合的验证异常。

部分源码分析：ABP框架中主要经过拦截器ValidationInterceptor(AOP实现方式之一，)实现验证，该拦截器在ValidationInterceptorRegistrar的Initialize方法中调用。

internal static class ValidationInterceptorRegistrar
    {
        public static void Initialize(IIocManager iocManager)
        {
            iocManager.IocContainer.Kernel.ComponentRegistered += Kernel_ComponentRegistered;
        }

        private static void Kernel_ComponentRegistered(string key, IHandler handler)
        {
            if (typeof(IApplicationService).GetTypeInfo().IsAssignableFrom(handler.ComponentModel.Implementation))
            {
                handler.ComponentModel.Interceptors.Add(new InterceptorReference(typeof(ValidationInterceptor)));
            }
        }
    }

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 public class ValidationInterceptor : IInterceptor
    {
        private readonly IIocResolver _iocResolver;

        public ValidationInterceptor(IIocResolver iocResolver)
        {
            _iocResolver = iocResolver;
        }

        public void Intercept(IInvocation invocation)
        {
            if (AbpCrossCuttingConcerns.IsApplied(invocation.InvocationTarget, AbpCrossCuttingConcerns.Validation))
            {
                invocation.Proceed();
                return;
            }

            using (var validator = _iocResolver.ResolveAsDisposable<MethodInvocationValidator>())
            {
                validator.Object.Initialize(invocation.MethodInvocationTarget, invocation.Arguments);
                validator.Object.Validate();
            }
            
            invocation.Proceed();
        }
    }

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自定义Customvalidator类

 public class CustomValidator : IMethodParameterValidator
    {
        private readonly IIocResolver _iocResolver;

        public CustomValidator(IIocResolver iocResolver)
        {
            _iocResolver = iocResolver;
        }

        public IReadOnlyList<ValidationResult> Validate(object validatingObject)
        {
            var validationErrors = new List<ValidationResult>();

            if (validatingObject is ICustomValidate customValidateObject)
            {
                var context = new CustomValidationContext(validationErrors, _iocResolver);
                customValidateObject.AddValidationErrors(context);
            }

            return validationErrors;
        }
    }

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审计日志(Audit Logging)：基于约定和配置，用户、浏览器、IP地址、调用服务、方法、参数、调用时间、执行时长以及其它信息会为每个请求自动保存。

部分源码分析：ABP框架中主要经过拦截器AuditingInterceptor(AOP实现方式之一，)实现审计日志，该拦截器在AuditingInterceptorRegistrar的Initialize方法中调用。

internal static class AuditingInterceptorRegistrar
    {
        public static void Initialize(IIocManager iocManager)
        {
            iocManager.IocContainer.Kernel.ComponentRegistered += (key, handler) =>
            {
                if (!iocManager.IsRegistered<IAuditingConfiguration>())
                {
                    return;
                }

                var auditingConfiguration = iocManager.Resolve<IAuditingConfiguration>();

                if (ShouldIntercept(auditingConfiguration, handler.ComponentModel.Implementation))
                {
                    handler.ComponentModel.Interceptors.Add(new InterceptorReference(typeof(AuditingInterceptor)));
                }
            };
        }

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        private static bool ShouldIntercept(IAuditingConfiguration auditingConfiguration, Type type)
        {
            if (auditingConfiguration.Selectors.Any(selector => selector.Predicate(type)))
            {
                return true;
            }

            if (type.GetTypeInfo().IsDefined(typeof(AuditedAttribute), true))
            {
                return true;
            }

            if (type.GetMethods().Any(m => m.IsDefined(typeof(AuditedAttribute), true)))
            {
                return true;
            }

            return false;
        }
    }

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 internal class AuditingInterceptor : IInterceptor
    {
        private readonly IAuditingHelper _auditingHelper;

        public AuditingInterceptor(IAuditingHelper auditingHelper)
        {
            _auditingHelper = auditingHelper;
        }

        public void Intercept(IInvocation invocation)
        {
            if (AbpCrossCuttingConcerns.IsApplied(invocation.InvocationTarget, 
               AbpCrossCuttingConcerns.Auditing))
            {
                invocation.Proceed();
                return;
            }

            if (!_auditingHelper.ShouldSaveAudit(invocation.MethodInvocationTarget))
            {
                invocation.Proceed();
                return;
            }

            var auditInfo = _auditingHelper.CreateAuditInfo(invocation.TargetType, 
            invocation.MethodInvocationTarget, invocation.Arguments);

            if (invocation.Method.IsAsync())
            {
                PerformAsyncAuditing(invocation, auditInfo);
            }
            else
            {
                PerformSyncAuditing(invocation, auditInfo);
            }
        }

        private void PerformSyncAuditing(IInvocation invocation, AuditInfo auditInfo)
        {
            var stopwatch = Stopwatch.StartNew();

            try
            {
                invocation.Proceed();
            }
            catch (Exception ex)
            {
                auditInfo.Exception = ex;
                throw;
            }
            finally
            {
                stopwatch.Stop();
                auditInfo.ExecutionDuration = 
                Convert.ToInt32(stopwatch.Elapsed.TotalMilliseconds);
                _auditingHelper.Save(auditInfo);
            }
        }

        private void PerformAsyncAuditing(IInvocation invocation, AuditInfo auditInfo)
        {
            var stopwatch = Stopwatch.StartNew();

            invocation.Proceed();

            if (invocation.Method.ReturnType == typeof(Task))
            {
                invocation.ReturnValue = InternalAsyncHelper.AwaitTaskWithFinally(
                    (Task) invocation.ReturnValue,
                    exception => SaveAuditInfo(auditInfo, stopwatch, exception)
                    );
            }
            else //Task<TResult>
            {
                invocation.ReturnValue = 
                InternalAsyncHelper.CallAwaitTaskWithFinallyAndGetResult(
                    invocation.Method.ReturnType.GenericTypeArguments[0],
                    invocation.ReturnValue,
                    exception => SaveAuditInfo(auditInfo, stopwatch, exception)
                    );
            }
        }

        private void SaveAuditInfo(AuditInfo auditInfo, Stopwatch stopwatch, Exception 
        exception)
        {
            stopwatch.Stop();
            auditInfo.Exception = exception;
            auditInfo.ExecutionDuration = 
            Convert.ToInt32(stopwatch.Elapsed.TotalMilliseconds);

            _auditingHelper.Save(auditInfo);
        }
    }

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工做单元(Unit Of Work)：在ABP中，应用服务方法默认视为一个工做单元。它会自动建立一个链接并在方法的开始位置开启事务。若是方法成功完成并无异常，事务会提交并释放链接。即便这个方法使用不一样的仓储或方法，它们都是原子的(事务的)。当事务提交时，实体的全部改变都会自动保存。如上述事例所示，甚至不须要调用_repository.Update(task)方法。

部分源码分析：ABP框架中主要经过拦截器UnitOfWorkInterceptor(AOP实现方式之一，)实现工做单元，该拦截器在UnitOfWorkRegistrar的Initialize方法中调用。

internal class UnitOfWorkInterceptor : IInterceptor
    {
        private readonly IUnitOfWorkManager _unitOfWorkManager;
        private readonly IUnitOfWorkDefaultOptions _unitOfWorkOptions;

        public UnitOfWorkInterceptor(IUnitOfWorkManager unitOfWorkManager, IUnitOfWorkDefaultOptions unitOfWorkOptions)
        {
            _unitOfWorkManager = unitOfWorkManager;
            _unitOfWorkOptions = unitOfWorkOptions;
        }

        /// <summary>
        /// Intercepts a method.
        /// </summary>
        /// <param name="invocation">Method invocation arguments</param>
        public void Intercept(IInvocation invocation)
        {
            MethodInfo method;
            try
            {
                method = invocation.MethodInvocationTarget;
            }
            catch
            {
                method = invocation.GetConcreteMethod();
            }

            var unitOfWorkAttr = _unitOfWorkOptions.GetUnitOfWorkAttributeOrNull(method);
            if (unitOfWorkAttr == null || unitOfWorkAttr.IsDisabled)
            {
                //No need to a uow
                invocation.Proceed();
                return;
            }

            //No current uow, run a new one
            PerformUow(invocation, unitOfWorkAttr.CreateOptions());
        }

        private void PerformUow(IInvocation invocation, UnitOfWorkOptions options)
        {
            if (invocation.Method.IsAsync())
            {
                PerformAsyncUow(invocation, options);
            }
            else
            {
                PerformSyncUow(invocation, options);
            }
        }

        private void PerformSyncUow(IInvocation invocation, UnitOfWorkOptions options)
        {
            using (var uow = _unitOfWorkManager.Begin(options))
            {
                invocation.Proceed();
                uow.Complete();
            }
        }

        private void PerformAsyncUow(IInvocation invocation, UnitOfWorkOptions options)
        {
            var uow = _unitOfWorkManager.Begin(options);

            try
            {
                invocation.Proceed();
            }
            catch
            {
                uow.Dispose();
                throw;
            }

            if (invocation.Method.ReturnType == typeof(Task))
            {
                invocation.ReturnValue = InternalAsyncHelper.AwaitTaskWithPostActionAndFinally(
                    (Task) invocation.ReturnValue,
                    async () => await uow.CompleteAsync(),
                    exception => uow.Dispose()
                );
            }
            else //Task<TResult>
            {
                invocation.ReturnValue = InternalAsyncHelper.CallAwaitTaskWithPostActionAndFinallyAndGetResult(
                    invocation.Method.ReturnType.GenericTypeArguments[0],
                    invocation.ReturnValue,
                    async () => await uow.CompleteAsync(),
                    exception => uow.Dispose()
                );
            }
        }
    }

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异常处理(Exception)：在使用了ABP框架的Web应用程序中，咱们几乎不用手动处理异常。默认状况下，全部的异常都会自动处理。若是发生异常，ABP会自动记录并给客户端返回合适的结果。例如：对于一个ajax请求，返回一个json对象给客户端，代表发生了错误。但会对客户端隐藏实际的异常，除非像上述事例那样使用UserFriendlyException方法抛出。它也理解和处理客户端的错误，并向客户端显示合适的信息。

部分源码分析：UserFriendlyException抛出异常方法。

 [Serializable]
    public class UserFriendlyException : AbpException, IHasLogSeverity, IHasErrorCode
    {
        /// <summary>
        /// Additional information about the exception.
        /// </summary>
        public string Details { get; private set; }

        /// <summary>
        /// An arbitrary error code.
        /// </summary>
        public int Code { get; set; }

        /// <summary>
        /// Severity of the exception.
        /// Default: Warn.
        /// </summary>
        public LogSeverity Severity { get; set; }

        /// <summary>
        /// Constructor.
        /// </summary>
        public UserFriendlyException()
        {
            Severity = LogSeverity.Warn;
        }

        /// <summary>
        /// Constructor for serializing.
        /// </summary>
        public UserFriendlyException(SerializationInfo serializationInfo, StreamingContext context)
            : base(serializationInfo, context)
        {

        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="message">Exception message</param>
        public UserFriendlyException(string message)
            : base(message)
        {
            Severity = LogSeverity.Warn;
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="message">Exception message</param>
        /// <param name="severity">Exception severity</param>
        public UserFriendlyException(string message, LogSeverity severity)
            : base(message)
        {
            Severity = severity;
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="code">Error code</param>
        /// <param name="message">Exception message</param>
        public UserFriendlyException(int code, string message)
            : this(message)
        {
            Code = code;
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="message">Exception message</param>
        /// <param name="details">Additional information about the exception</param>
        public UserFriendlyException(string message, string details)
            : this(message)
        {
            Details = details;
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="code">Error code</param>
        /// <param name="message">Exception message</param>
        /// <param name="details">Additional information about the exception</param>
        public UserFriendlyException(int code, string message, string details)
            : this(message, details)
        {
            Code = code;
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="message">Exception message</param>
        /// <param name="innerException">Inner exception</param>
        public UserFriendlyException(string message, Exception innerException)
            : base(message, innerException)
        {
            Severity = LogSeverity.Warn;
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="message">Exception message</param>
        /// <param name="details">Additional information about the exception</param>
        /// <param name="innerException">Inner exception</param>
        public UserFriendlyException(string message, string details, Exception innerException)
            : this(message, innerException)
        {
            Details = details;
        }
    }

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日志(Logging)：由上述事例可见，能够经过在基类定义的Logger对象来写日志。ABP默认使用了Log4Net，但它是可更改和可配置的。

部分源码分析：Log4NetLoggerFactory类。

 public class Log4NetLoggerFactory : AbstractLoggerFactory
    {
        internal const string DefaultConfigFileName = "log4net.config";
        private readonly ILoggerRepository _loggerRepository;

        public Log4NetLoggerFactory()
            : this(DefaultConfigFileName)
        {
        }

        public Log4NetLoggerFactory(string configFileName)
        {
            _loggerRepository = LogManager.CreateRepository(
                typeof(Log4NetLoggerFactory).GetAssembly(),
                typeof(log4net.Repository.Hierarchy.Hierarchy)
            );

            var log4NetConfig = new XmlDocument();
            log4NetConfig.Load(File.OpenRead(configFileName));
            XmlConfigurator.Configure(_loggerRepository, log4NetConfig["log4net"]);
        }

        public override ILogger Create(string name)
        {
            if (name == null)
            {
                throw new ArgumentNullException(nameof(name));
            }

            return new Log4NetLogger(LogManager.GetLogger(_loggerRepository.Name, name), this);
        }

        public override ILogger Create(string name, LoggerLevel level)
        {
            throw new NotSupportedException("Logger levels cannot be set at runtime. Please review your configuration file.");
        }
    }

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本地化(Localization)：注意，在上述事例中使用了L("XXX")方法处理抛出的异常。所以，它会基于当前用户的文化自动实现本地化。详细见后续本地化章节。

部分源码分析：......

自动映射(Auto Mapping)：在上述事例最后一行代码，使用了ABP的MapTo扩展方法将输入对象的属性映射到实体属性。ABP使用AutoMapper第三方库执行映射。根据命名惯例能够很容易的将属性从一个对象映射到另外一个对象。

部分源码分析：AutoMapExtensions类中的MapTo()方法。

 public static class AutoMapExtensions
    {

        public static TDestination MapTo<TDestination>(this object source)
        {
            return Mapper.Map<TDestination>(source);
        }


        public static TDestination MapTo<TSource, TDestination>(this TSource source, TDestination destination)
        {
            return Mapper.Map(source, destination);
        }

        ......
  }

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动态API层(Dynamic API Layer)：在上述事例中，TaskAppService其实是一个简单的类。一般必须编写一个Web API Controller包装器给js客户端暴露方法，而ABP会在运行时自动完成。经过这种方式，能够在客户端直接使用应用服务方法。

部分源码分析：......

动态javascript ajax代理(Dynamic JavaScript AJAX Proxy)：ABP建立动态代理方法，从而使得调用应用服务方法就像调用客户端的js方法同样简单。

部分源码分析：......

4.本章小节

经过上述简单的类能够看到ABP的优势。完成全部这些任务一般须要花费大量的时间，可是ABP框架会自动处理。

除了这个上述简单的事例外，ABP还提供了一个健壮的基础设施和开发模型，如模块化、多租户、缓存、后台工做、数据过滤、设置管理、领域事件、单元&集成测试等等，那么你能够专一于业务代码，而不须要重复作这些工做(DRY)。