轻量级.Net Core服务注册工具CodeDi发布啦

为什么做这么一个工具

因为我们的系统往往时面向接口编程的,所以在开发Asp .net core项目的时候,一定会有大量大接口及其对应的实现要在ConfigureService注册到ServiceCollection中,传统的做法是加了一个服务,我们就要注册一次(service.AddService()),又比如,当一个接口有多个实现,在构造函数中获取服务也不是很友好,而据我所知, .Net Core目前是没有什么自带的库或者方法解决这些问题,当然,如果引入第三方容器如AutoFac这些问题时能迎刃而解的,但是如何在不引入第三方容器来解决这个问题呢?
所以我就设计了这样的一个轻量级工具.

首先,放上该项目的Github地址(记得Star哦!!)

https://github.com/liuzhenyulive/CodeDi

CodeDi是一个基于 .Net Standard的工具库,它能帮助我们自动地在Asp .net core或者 .net core项目中完成服务的注册.

Overview

CodeDi 是 Code Dependency Injection的意思,在上次我在看了由依乐祝写的<.NET Core中的一个接口多种实现的依赖注入与动态选择看这篇就够了>后,回想起我之前遇到的那些问题,感觉拨云见日,所以,我就开始着手写这个工具了.

如何使用CodeDi

安装Nuget包

CodeDi的Nuget包已经发布到了 nuget.org,您可以通过以下指令在您的项目中安装CodeDi

PM> Install-Package CodeDi

ConfigureServices中的配置

方法 1

您可以在Startup的ConfigureService方法中添加AddCodeDi完成对CodeDi的调用.服务的注册CodeDi会自动为您完成.

 ???????public void ConfigureServices(IServiceCollection services) ???????{ ???????????services.AddCoreDi(); ???????????services.AddMvc(); ???????}

方法 2

您也可以在AddCodeDi方法中传入一个Action<CodeDiOptions>参数,在这个action中,您可以对CodeDiOptions的属性进行配置.

 ??????public void ConfigureServices(IServiceCollection services) ???????{ ???????????services.AddCoreDi(options => ???????????{ ???????????????options.DefaultServiceLifetime = ServiceLifetime.Scoped; ???????????}); ???????????services.AddMvc(); ???????}

方法 3

当然您也可以直接给AddCodeDi()方法直接传入一个CodeDiOptions实例.

 ???????public void ConfigureServices(IServiceCollection services) ???????{ ???????????services.AddCoreDi(new CodeDiOptions() ???????????{ ???????????????DefaultServiceLifetime = ServiceLifetime.Scoped ???????????}); ???????????services.AddMvc(); ???????}

你也可以在appsetting.json文件中配置CodeDiOptions的信息,并通过Configuration.Bind("CodeDiOptions", options)把配置信息绑定到一个CodeDiOptions实例.

appsetting.json file

{ ?"Logging": { ???"LogLevel": { ?????"Default": "Warning" ???} ?}, ?"AllowedHosts": "*", ?"CodeDiOptions": { ???"DefaultServiceLifetime": 1, ???"AssemblyNames": [ ?????"*CodeDi" ???], ???"AssemblyPaths": [ ?????"C:\\MyBox\\Github\\CodeDI\\CodeDI\\bin\\Debug\\netstandard2.0" ???], ???"IgnoreAssemblies": [ ?????"*Test" ???], ???"IncludeSystemAssemblies": false, ???"IgnoreInterface": [ ?????"*Say" ???], ???"InterfaceMappings": { ?????"*Say": "*English" ???}, ???"ServiceLifeTimeMappings": { ?????"*Say": 0 ???} ?}}

ConfigureService方法

 ???????public void ConfigureServices(IServiceCollection services) ???????{ ???????????var options=new CodeDiOptions(); ???????????Configuration.Bind("CodeDiOptions", options); ???????????services.AddCoreDi(options); ???????????services.AddMvc(); ???????}

CodeDiOptions详解

InterfaceMappings

如果 ISay 接口有SayInChinese 和SayInEnglish 两个实现,我们只想把SayInEnglish注册到ServiceCollection中

 public interface ISay ???{ ???????string Hello(); ???} ?????public class SayInChinese:ISay ???{ ???????public string Hello() ???????{ ???????????return "您好"; ???????} ???} ???????public class SayInEnglish:ISay ???{ ???????public string Hello() ???????{ ???????????return "Hello"; ???????} ???}

那么我们可以这样配置InterfaceMappings.

options.InterfaceMappings=new Dictionary<string, string>(){{ "ISay", "SayInChinese" } }

也就是{接口名称(支持通配符),实现名称(支持通配符)}

ServiceLifeTimeMappings

如果我们希望ISay接口的服务的生命周期为Singleton,我们可以这样配置ServiceLifeTimeMappings.

options.ServiceLifeTimeMappings = new Dictionary<string, ServiceLifetime>(){{"*Say",ServiceLifetime.Singleton}};

也就是也就是{接口名称(支持通配符),Servicelifetime}

关于ServiceLifetime: https://github.com/aspnet/DependencyInjection/blob/master/src/DI.Abstractions/ServiceLifetime.cs

获取服务实例

当然, 您可以和之前一样,直接在构造函数中进行依赖的注入,但是当某个接口有多个实现而且都注册到了ServiceCollection中,获取就没有那么方便了,您可以用ICodeDiServiceProvider 来帮助您获取服务实例.

例如,当 ISay 接口有 SayInChinese 和 SayInEnglish两个实现, 我们我们如何获取我们想要的服务实例呢?

 public interface ISay ???{ ???????string Hello(); ???} ?????public class SayInChinese:ISay ???{ ???????public string Hello() ???????{ ???????????return "您好"; ???????} ???} ???????public class SayInEnglish:ISay ???{ ???????public string Hello() ???????{ ???????????return "Hello"; ???????} ???}

 public class HomeController : Controller ???{ ???????private readonly ISay _say; ???????public HomeController(ICodeDiServiceProvider serviceProvider) ???????{ ???????????_say = serviceProvider.GetService<ISay>("*Chinese"); ???????} ???????public string Index() ???????{ ???????????return _say.Hello(); ???????} ???}

ICodeDiServiceProvider.GetService<T>(string name=null)
参数中的Name支持通配符.

CodeDi如何实现的?

既然是一个轻量级工具,那么实现起来自然不会太复杂,我来说说比较核心的代码.

 ?private Dictionary<Type, List<Type>> GetInterfaceMapping(IList<Assembly> assemblies) ???????{ ???????????var mappings = new Dictionary<Type, List<Type>>(); ???????????var allInterfaces = assemblies.SelectMany(u => u.GetTypes()).Where(u => u.IsInterface); ???????????foreach (var @interface in allInterfaces) ???????????{ ???????????????mappings.Add(@interface, assemblies.SelectMany(a => ???????????????????????a.GetTypes(). ???????????????????????????Where(t => ???????????????????????????????t.GetInterfaces().Contains(@interface) ???????????????????????????) ???????????????????) ???????????????????.ToList()); ???????????} ???????????return mappings; ???????}

GetInterfaceMapping通过反射机制,首先获取程序集中的所有接口allInterfaces,然后遍历allInterfaces找到该接口对应的实现,最终,该方法返回接口和实现的匹配关系,为Dictionary<Type, List>类型的数据.

 ???????private void AddToService(Dictionary<Type, List<Type>> interfaceMappings) ???????{ ???????????foreach (var mapping in interfaceMappings) ???????????{ ???????????????if (mapping.Key.FullName == null || (_options.IgnoreInterface != null && ??????????????????_options.IgnoreInterface.Any(i => mapping.Key.FullName.Matches(i)))) ???????????????????continue; ???????????????if (mapping.Key.FullName != null && _options.InterfaceMappings != null && ???????????????????_options.InterfaceMappings.Any(u => mapping.Key.FullName.Matches(u.Key))) ???????????????{ ???????????????????foreach (var item in mapping.Value.Where(value => value.FullName != null). ???????????????????????Where(value => value.FullName.Matches(_options.InterfaceMappings.FirstOrDefault(u => mapping.Key.FullName.Matches(u.Key)).Value))) ???????????????????{ ???????????????????????AddToService(mapping.Key, item); ???????????????????} ???????????????????continue; ???????????????} ???????????????foreach (var item in mapping.Value) ???????????????{ ???????????????????AddToService(mapping.Key, item); ???????????????} ???????????} ???????}

该方法要判断CodeDiOptions中是否忽略了该接口,同时,是否指定实现映射关系.
什么叫实现映射关系呢?参见InterfaceMappings
如果指定了,那么就按指定的来实现,如果没指定,就会把每个实现都注册到ServiceCollection中.

 ???????private readonly IServiceCollection _service; ???????private readonly CodeDiOptions _options; ???????private readonly ServiceDescriptor[] _addedService; ???????public CodeDiService(IServiceCollection service, CodeDiOptions options) ???????{ ???????????_service = service ?? throw new ArgumentNullException(nameof(service)); ???????????_options = options ?? new CodeDiOptions(); ???????????_addedService = new ServiceDescriptor[service.Count]; ???????????service.CopyTo(_addedService, 0); ???????????//在构造函数中,我们通过这种方式把Service中已经添加的服务读取出来 ???????????//后面进行服务注册时,会进行判断,避免重复添加 ???????} ???????private void AddToService(Type serviceType, Type implementationType) ???????{ ???????????ServiceLifetime serviceLifetime; ???????????try ???????????{ ???????????????serviceLifetime = _options.DefaultServiceLifetime; ???????????????if (_options.ServiceLifeTimeMappings != null && serviceType.FullName != null) ???????????????{ ???????????????????var lifeTimeMapping = ???????????????????????_options.ServiceLifeTimeMappings.FirstOrDefault(u => serviceType.FullName.Matches(u.Key)); ???????????????????serviceLifetime = lifeTimeMapping.Key != null ? lifeTimeMapping.Value : _options.DefaultServiceLifetime; ???????????????} ???????????} ???????????catch ???????????{ ???????????????throw new Exception("Service Life Time Only Can be set in range of 0-2"); ???????????} ???????????if (_addedService.Where(u => u.ServiceType == serviceType).Any(u => u.ImplementationType == implementationType)) ???????????????return; ???????????_service.Add(new ServiceDescriptor(serviceType, implementationType, serviceLifetime)); ???????}

AddToService中,要判断有没有对接口的生命周期进行配置,参见ServiceLifeTimeMappings,如果没有配置,就按DefaultServiceLifetime进行配置,DefaultServiceLifetime如果没有修改的情况下时ServiceLifetime.Scoped,即每个Request创建一个实例.

 ???????private readonly IServiceProvider _serviceProvider; ???????public CodeDiServiceProvider(IServiceProvider serviceProvider) ???????{ ???????????_serviceProvider = serviceProvider; ???????} ???????public T GetService<T>(string name) where T : class ???????{ ???????????return _serviceProvider.GetService<IEnumerable<T>>().FirstOrDefault(u => u.GetType().Name.Matches( name)); ???????}

这CodeDiServiceProvider的实现代码,这里参考了依乐祝写的<.NET Core中的一个接口多种实现的依赖注入与动态选择看这篇就够了>给出的一种解决方案,即当某个接口注册了多个实现,其实可以通过IEnumerable获取所有的实现,CodeDiServiceProvider对其进行了封装.

Enjoy it

只要进行一次简单的CodeDi配置,以后系统中添加了新的接口以及对应的服务实现后,就不用再去一个个地Add到IServiceCollection中了.

如果有问题,欢迎Issue,欢迎PR.
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轻量级.Net Core服务注册工具CodeDi发布啦

原文地址：https://www.cnblogs.com/CoderAyu/p/10269610.html