Spectre.Console.Cli注入服务的几种姿势
Spectre.Console.NET程序员可能都不陌生,写控制台程序美化还是不错的,支持着色,表格,图标等相当Nice,如果对这个库不熟悉我强烈推荐你了解一下,Spectre.Console.Cli作为Spectre.Console的子集,对于写一些CLI小工具还是相当方便
本文主要讲讲 Spectre.Console.Cli的服务注入, TA是 Spectre.Console 库的一部分，用于创建命令行界面（CLI）应用程序。TA提供了一个强大且易于使用的API来定义命令、参数和选项，同时支持 Spectre.Console 的丰富输出格式化功能。
一个官方极简的CLI例子,定义一个GreetCommand:
public class GreetCommand : Command<GreetCommand.Settings>
{
public class Settings : CommandSettings
{
[CommandArgument(0, "<name>")]
[Description("The name of the person to greet.")]
public string Name { get; set; }
[CommandOption("-r|--repeat <times>")]
[Description("The number of times to repeat the greeting.")]
[DefaultValue(1)]
public int Repeat { get; set; }
}
public override int Execute(CommandContext context, Settings settings)
{
for (int i = 0; i < settings.Repeat; i++)
{
Console.WriteLine($"Hello, {settings.Name}!");
}
return 0;
}
}
接下来，在程序的入口点配置Command
public class Program
{
public static int Main(string[] args)
{
var app = new CommandApp();
app.Configure(config =>
{
config.AddCommand<GreetCommand>("greet");
});
return app.Run(args);
}
}
对于Spectre.Console.Cli的常规使用我这里不做过多介绍,感兴趣的同学可以移步官方文档,本文主要讲一下在CLI程序中如何注入服务
那么我们需要在GreetCommand中注入服务应该怎么做呢? 比如下面的一个服务:
public class HelloService(ILogger<HelloService> logger)
{
public Task<string> SayHello(string name, int age)
{
//注入的logger
logger.LogInformation("SayHello called with name:{name},age:{age}", name, age);
return Task.FromResult($"Hello,My name is {name}, I`m {age} years old!");
}
}
其实Spectre.Console.Cli内置了最简单的方式,我们只需要在app.Configure中完成:
var services = new ServiceCollection();
//添加服务
services.AddSingleton<HelloService>();
//添加日志
services.AddLogging(config =>
{
config.AddConsole();
});
var sp = services.BuildServiceProvider();
app.Configure(config =>
{
//添加Commands
config.AddCommand<OneCommand>("one");
config.AddCommand<AnotherCommand>("another");
//注册Services
config.Settings.Registrar.RegisterInstance(sp.GetRequiredService<HelloService>());
});
注册的服务就可以直接使用了:
public class HelloCommand(HelloService helloService) : AsyncCommand<HelloCommand.HelloSettings>
{
private readonly HelloService _helloService = helloService;
public class HelloSettings : CommandSettings
{
[CommandArgument(0, "<name>")]
[Description("The target to say hello to.")]
public string Name { get; set; } = null!;
}
public override async Task<int> ExecuteAsync(CommandContext context, HelloSettings settings)
{
var message = await _helloService.SayHello(settings.Name, settings.Age);
AnsiConsole.MarkupLine($"[blue]{message}[/]");
return 0;
}
}
另外的一个注入方式是实现ITypeRegistrar,官方提供MSDI的用例,自己也可以实现Autofac等其他DI,下面是MSDI的实现:
namespace Infrastructure
{
public sealed class MsDITypeRegistrar(IServiceCollection services) : ITypeRegistrar
{
private readonly IServiceCollection _services =
services ?? throw new ArgumentNullException(nameof(services));
public ITypeResolver Build()
{
return new TypeResolver(_services.BuildServiceProvider());
}
public void Register(Type service, Type implementation)
{
_services.AddSingleton(service, implementation);
}
public void RegisterInstance(Type service, object implementation)
{
_services.AddSingleton(service, implementation);
}
public void RegisterLazy(Type service, Func<object> factory)
{
_services.AddSingleton(service, (provider) => factory());
}
}
internal sealed class TypeResolver(IServiceProvider provider) : ITypeResolver
{
public object? Resolve(Type? type)
{
if (provider is null || type is null)
{
return null;
}
return ActivatorUtilities.GetServiceOrCreateInstance(provider, type);
}
}
}
使用的话只需要实例化CommandApp时候传入MsDITypeRegistrar即可:
var services = new ServiceCollection();
//添加服务...
var app = new CommandApp(new MsDITypeRegistrar(services));
app.Configure(config =>
{
//...
});
return app.Run(args);
除了上面的方式,我们其实还可以使用ICommandInterceptor切面的方式来完成注入的操作:
下面我们定义一个AutoDIAttribute特性,实现一个AutoDIInterceptor的拦截器,后者主要给标记了AutoDI的属性服务赋值
[AttributeUsage(AttributeTargets.Property, Inherited = true)]
public class AutoDIAttribute : Attribute{ }
/// <summary>
/// 自动注入的拦截器
/// </summary>
internal class AutoDIInterceptor(IServiceProvider serviceProvider) : ICommandInterceptor
{
public void Intercept(CommandContext context, CommandSettings settings)
{
var type = settings.GetType();
var properties = type.GetProperties();
foreach (var property in properties)
{
var isAutoInject = property.GetCustomAttributes<AutoDIAttribute>(true).Any();
if (isAutoInject)
{
var service = ActivatorUtilities.GetServiceOrCreateInstance(serviceProvider, property.PropertyType);
property.SetValue(settings, service);
}
}
}
}
接下来在CommandSettings中标记需要自动注入服务的属性,如下面的HelloService:
internal class AutoDICommand : AsyncCommand<AutoDICommand.AnotherInjectSettings>
{
public class AnotherInjectSettings : CommandSettings
{
/// <summary>
/// 使用切面装载的服务
/// </summary>
[AutoDI]
public HelloService HelloService { get; set; } = null!;
[Description("user name")]
[DefaultValue("vipwan"), CommandOption("-n|--name")]
public string Name { get; set; } = null!;
[Description("user age")]
[DefaultValue(12), CommandOption("-a|--age")]
public int Age { get; set; }
}
public override async Task<int> ExecuteAsync(CommandContext context, AnotherInjectSettings settings)
{
var message = await settings.HelloService.SayHello(settings.Name, settings.Age);
AnsiConsole.MarkupLine($"[green]{message}[/]");
return 0;
}
}
然后在app.Configure中使用AutoDIInterceptor切面:
var services = new ServiceCollection();
//添加服务
services.AddSingleton<HelloService>();
var sp = services.BuildServiceProvider();
app.Configure(config =>
{
//设置自动注入的拦截器
config.SetInterceptor(new AutoDIInterceptor(sp));
config.AddCommand<AutoDICommand>("di");
//...
});
然后测试运行程序:
dotnet run -- di -n "vipwan"
大功告成:
以上就介绍了几种在Spectre.Console.Cli注入服务的方式,当然没有最优的只有最适合自己的,如果代码存在不足,或者你有更好的建议 欢迎留言交流!
