.net core 使用IOptionsXXX读取配置

add following packages

  <ItemGroup>
    <PackageReference Include="microsoft.extensions.configuration" Version="6.0.0" />
    <PackageReference Include="microsoft.extensions.configuration.binder" Version="6.0.0" />
    <PackageReference Include="microsoft.extensions.configuration.json" Version="6.0.0" />
    <PackageReference Include="microsoft.extensions.dependencyinjection" Version="6.0.0" />
    <PackageReference Include="microsoft.extensions.options" Version="6.0.0" />
  </ItemGroup>

sample code

class Config
{
    public string Name { get; set; }
    public int Age { get; set; }
    public Proxy Proxy { get; set; }

    public override string ToString()
    {
        return $"name:{Name}, age:{Age}, proxy:{Proxy}";
    }
}

class Proxy
{
    public string Server { get; set; }
    public int Port { get; set; }

    public override string ToString()
    {
        return $"server:{Server}, port:{Port}";
    }
}

class TestController
{
    // IOptions: 只读配置，不追踪变化
    // IOptionsSnapshot: 在scope内配置不会变，出了scope或进入新scope就会更新变化
    // IOptionsMonitor: 追踪配置变化
    private IOptionsSnapshot<Config> optConfig { get; }

    public TestController(IOptionsSnapshot<Config> config)
    {
        optConfig = config;
    }

    public void Test()
    {
        System.Console.WriteLine(optConfig.Value);
    }
}

从json文件读取

class Program
{
    static void Main(string[] args)
    {
        ServiceCollection services = new ServiceCollection();

        services.AddScoped<TestController>();

        ConfigurationBuilder builder = new ConfigurationBuilder();

        builder.AddJsonFile("config.json", true, true);

        IConfigurationRoot configRoot = builder.Build();
        services.AddOptions()
            .Configure<Config>(e => configRoot.Bind(e));   // 绑定Config对象
            //.Configure<Proxy>(e => configRoot.GetSection("proxy").Bind(e)); // 也可以只绑定Proxy对象

        using (ServiceProvider provider = services.BuildServiceProvider())
        {
            int count = 5;

            while (count-- > 0)
            {
                using (IServiceScope scope = provider.CreateScope())
                {
                    IServiceProvider sp = scope.ServiceProvider;
                    TestController test1 = sp.GetService<TestController>();

                    test1.Test();
                }

                System.Console.WriteLine($"press return to continue, {count} remaining...");
                System.Console.ReadLine();

                // change config value here, would reflect the changes in above Test() call.
            }
        }
    }
}

从命令行读取

static void Main(string[] args)
{
    ServiceCollection services = new ServiceCollection();

    services.AddScoped<TestController>();

    ConfigurationBuilder builder = new ConfigurationBuilder();

    builder.AddCommandLine(args);  // 加入命令行支持
    builder.AddEnvironmentVariables("prefix_");  // 加入环境变量支持，建议使用前缀，避免和其他系统冲突。

    IConfigurationRoot configRoot = builder.Build();
    services.AddOptions()
        .Configure<Config>(e => configRoot.Bind(e));   // bind to Config 
        //.Configure<Proxy>(e => configRoot.GetSection("proxy").Bind(e)); // bind to Proxy part only.

    using (ServiceProvider provider = services.BuildServiceProvider())
    {
        TestController test1 = provider.GetService<TestController>();

        test1.Test();
    }
}

// 命令行调用
dotnet run --name abc --age 22 --proxy:server abc.ccc --proxy:port 888