Net6 Configuration & Options 原始碼分析 Part2 Options
第二部分主要記錄Options 模型
OptionsConfigurationServiceCollectionExtensions類提供了對Options 模型與配置系統的Configure方法的擴展
1. 直接使用Options
直接使用Options
在Starup ConfigService中經常會看到把一個拉姆達注冊成配置項例如：.Configure<Profile>(it ->it.age = 18)，我們稱這個拉姆達為Configure Action，其實這是使用了一個包裝類，包裝你的Configure Action委托，并把這個類的實體注冊到Service容器中，它實作IOptions與拉姆達如何映射的，這一切由OptionsServiceCollectionExtensions、OptionsFacotry等實作的，你也可以直接像下面這樣使用
var profile = new Servicecollection ().Addoptions().Configure<Profile>(it ->it.age = 18).BuildServiceProvider().GetRequiredService<IOptions<Profile>>().Value;
配置服務注冊原始碼分析/Configure Action包裝類的注冊
OptionsServiceCollectionExtensions 作為配置服務的擴展類下面有三種型別的擴展方法分別是Configure、PostConfigure、AddOptions，前兩所對應的服務為IConfigureOptions與IPostConfigureOptions 區別僅僅是為了實作配置Configure Action的執行時機，IPostConfigureOptions會后執行，而AddOptions本質上還是注冊前兩種，注冊成面上看起來AddOptions注冊的Configure Action具有了引數可以訪問其它DI內服務，
注意：就算你使用了三個注冊方式注冊一次或多次對同一個TOptions進行注冊，他們其實是操作的同一個TOptions給你，這體現在OptionsFactory.Create上，也是我們想要的效果，
以下代碼為Configure、PostConfigure的服務注冊邏輯，
Configure、PostConfigure、擴展方法注冊的 Configure Action會由IConfigureOptions與IPostConfigureOptions 介面對應的包裝類進行包裝，屬性均是Action，Configure Action的執行是在Configure方法中，IConfigureOptions
值得注意的是ConfigureAll如果你此方法去注入一個Name 為null 的 Configure Action包裝類邏輯體現在ConfigureNamedOptions.Configure/PostConfigureOptions.Configure方法上，，官方說法：“Configure ALL options instances, both named and default”翻譯后擴展方法將配置應用于所有選項，包括命名實體和默認實體，
Configure -> ConfigureNamedOptions
PostConfigure -> PostConfigureOptions
public static class OptionsServiceCollectionExtensions
{
...
public static IServiceCollection Configure<TOptions>(this IServiceCollection services!!, string? name, Action<TOptions> configureOptions!!)
where TOptions : class
{
services.AddOptions();
services.AddSingleton<IConfigureOptions<TOptions>>(new ConfigureNamedOptions<TOptions>(name, configureOptions));
return services;
}
public static IServiceCollection PostConfigure<TOptions>(this IServiceCollection services!!, string? name, Action<TOptions> configureOptions!!)
where TOptions : class
{
services.AddOptions();
services.AddSingleton<IPostConfigureOptions<TOptions>>(new PostConfigureOptions<TOptions>(name, configureOptions));
return services;
}
...
}
public class ConfigureNamedOptions<TOptions> : IConfigureNamedOptions<TOptions> where TOptions : class
{
public ConfigureNamedOptions(string? name, Action<TOptions>? action)
{
Name = name;
Action = action;
}
public virtual void Configure(string? name, TOptions options!!)
{
// Null name is used to configure all named options.// Name的過濾以及Configure 邏輯就是在這里體現的
if (Name == null || name == Name)
{
Action?.Invoke(options);
}
}
}
public class PostConfigureOptions<TOptions> : IPostConfigureOptions<TOptions> where TOptions : class
{
public PostConfigureOptions(string? name, Action<TOptions>? action)
{
Name = name;
Action = action;
}
public virtual void PostConfigure(string? name, TOptions options!!)
{
if (Name == null || name == Name)
{
Action?.Invoke(options);
}
}
}
以下代碼為AddOptions 的服務注冊邏輯，
AddOptions:此方法會幫你構建一個OptionsBuilder,并非向Service容器注入，而是利用其builder類的Configure方法向Service容器具體注入，其下面的大量多載 Configure方法會幫你創建基于IConfigureNamedOptions/IPostConfigureOptions不同數量的泛型類. 其目的就是為了解決在“ Configure Action”中使用其它服務，
設計思路很好可以參考整體思路大概是，先用AddOptions
擴展方法創建了一個OptionsBuilder 物件，然后呼叫它多載方法Configure<TService...>去創建具有多個泛型的ConfigureNamedOptions 物件，ConfigureNamedOptions的Configure在執行Action委托時會用serviceProvider獲取到TService泛型服務，作為引數傳入Action委托，這樣委托在真正被執行時就會拿到對應的服務，
public static class OptionsServiceCollectionExtensions
{
...
public static OptionsBuilder<TOptions> AddOptions<TOptions>(this IServiceCollection services!!, string? name)
where TOptions : class
{
services.AddOptions();
return new OptionsBuilder<TOptions>(services, name);
}
...
}
public class OptionsBuilder<TOptions> where TOptions : class
{
...
public virtual OptionsBuilder<TOptions> Configure<TDep>(Action<TOptions, TDep> configureOptions!!) where TDep : class
{
Services.AddTransient<IConfigureOptions<TOptions>>(sp =>
new ConfigureNamedOptions<TOptions, TDep>(Name, sp.GetRequiredService<TDep>(), configureOptions));
return this;
}
...
}
public class ConfigureNamedOptions<TOptions, TDep> : IConfigureNamedOptions<TOptions> {
...
public ConfigureNamedOptions(string? name, TDep dependency, Action<TOptions, TDep>? action)
{
Name = name;
Action = action;
Dependency = dependency;
}
public virtual void Configure(string? name, TOptions options!!)
{
// Null name is used to configure all named options.
if (Name == null || name == Name)
{
Action?.Invoke(options, Dependency);
}
}
...
}
總結
| 注入到服務的擴展方法（OptionsServiceCollectionExtensions） | 服務類 | 服務實作類 | 使用 | 生命周期 | 備注 |
|---|---|---|---|---|---|
| Configure | IConfigureOptions | ConfigureNamedOptions | 被OptonsFactory使用 | Singleton | ConfigureAll，在IPostConfigureOptions前執行Configure Action |
| PostConfigure | IPostConfigureOptions | PostConfigureOptions | 被OptonsFactory使用 | Singleton | ConfigureAll 在IConfigureOptions后執行Configure Action |
| AddOptions | IConfigureOptions/IPostConfigureOptions | ConfigureNamedOptions/PostConfigureOptions | 被OptonsFactory使用 | Singleton | 輔助注入一個可以訪問其它服務的Configure Action |
配置Otpns服務的使用
首先在固有想法上注入的服務直接會拿來使用，而在這里注入的均為IConfigureOptions/IPostConfigureOptions服務我們管他們叫Configure Action的包裝類，而要使用這些服務是通過IOptions/IOptionsSnapshot/IOptionsMonitor去獲得，我們稱這三個服務為OptionsManger類，
注冊的基礎服務（OptionsServiceCollectionExtensions.AddOptions）
這里整理出來IOptions/IOptionsSnapshot/IOptionsMonitor三種OptionsManger的區別，
服務類|服務實作類|使用|生命周期|備注|
---|:--??:--??:--??:--??--:
IOptions|UnnamedOptionsManager
IOptionsSnapshot|OptionsManager
IOptionsMonitor|OptionsMonitor
IOptions 使用Demo
var source = new Dictionary<string, string>{
{"TestOptions:Key1" ,"TestOptions key1"},
};
var config = new ConfigurationBuilder().Add(new MemoryConfigurationSource() { InitialData = https://www.cnblogs.com/hts92/p/source }).Build();
ServiceCollection services = new ServiceCollection();
services.AddOptions();
services.Configure(config.GetSection("TestOptions")); // Import the "Microsoft.Extensions.Options.ConfigurationExtensions" package.
var serviceProvider = services.BuildServiceProvider();
IOptions<TestOptions> options = serviceProvider.GetService<IOptions<TestOptions>>();
Console.WriteLine(options.Value.Key1);
Console.ReadLine();
public class TestOptions
{
public string Key1 { get; set; }
}
IOptions 使用原始碼分析
以第一個為例：UnnamedOptionsManager 的value屬性的get 訪問器其內部直接呼叫OptionsFactory
internal sealed class UnnamedOptionsManager<[DynamicallyAccessedMembers(Options.DynamicallyAccessedMembers)] TOptions> : IOptions<TOptions>where TOptions : class
{
private volatile TOptions? _value;
public UnnamedOptionsManager(IOptionsFactory<TOptions> factory) => _factory = factory;
public TOptions Value
{
get
{
if (_value is TOptions value)
{
return value;
}
return _value ??= _factory.Create(Options.DefaultName);
}
}
}
public class OptionsFactory<[DynamicallyAccessedMembers(Options.DynamicallyAccessedMembers)] TOptions> :
IOptionsFactory<TOptions>
where TOptions : class
{
...
public TOptions Create(string name)
{
// 創建Toptions 實體物件
TOptions options = CreateInstance(name);
// 依次呼叫注冊的 Configure Action
// 先執行IConfigureOptions包裝的Configure Action.
foreach (IConfigureOptions<TOptions> setup in _setups)
{
if (setup is IConfigureNamedOptions<TOptions> namedSetup)
{
namedSetup.Configure(name, options);
}
else if (name == Options.DefaultName)
{
setup.Configure(options);
}
}
// 在執行 IPostConfigureOptions包裝的Configure Action.
foreach (IPostConfigureOptions<TOptions> post in _postConfigures)
{
post.PostConfigure(name, options);
}
// 執行驗證邏輯
if (_validations.Length > 0)
{
var failures = new List<string>();
foreach (IValidateOptions<TOptions> validate in _validations)
{
ValidateOptionsResult result = validate.Validate(name, options);
if (result is not null && result.Failed)
{
failures.AddRange(result.Failures);
}
}
if (failures.Count > 0)
{
throw new OptionsValidationException(name, typeof(TOptions), failures);
}
}
return options;
}
...
}
IOptionsSnapshot 使用Demo
因實作邏輯基本與IOptons相同這里就不多做記錄，
var source = new Dictionary<string, string>{
{"TestOptions:Key1" ,"TestOptions key1"},
};
var config = new ConfigurationBuilder().Add(new MemoryConfigurationSource() { InitialData = https://www.cnblogs.com/hts92/p/source }).Build();
ServiceCollection services = new ServiceCollection();
services.AddOptions();
services.Configure("TestOptions", config.GetSection("TestOptions")); // Import the "Microsoft.Extensions.Options.ConfigurationExtensions" package.
var serviceProvider = services.BuildServiceProvider();
IOptionsSnapshot<TestOptions> optionsAccessor = serviceProvider.GetRequiredService<IOptionsSnapshot<TestOptions>>();
Console.WriteLine(optionsAccessor.Get("TestOptions").Key1);
Console.ReadLine();
public class TestOptions
{
public string Key1 { get; set; }
}
配置源的同步 IOptionsMonitor 的使用 Demo
原始碼在part3 單獨分析，
var configuration = new ConfigurationBuilder().AddJsonFile(path: "profile.json",
optional: false,
reloadOnChange: true).Build();
new ServiceCollection().AddOptions().Configure<Profile>(configuration).BuildServiceProvider().GetRequiredService<IOptionsMonitor<Profile>>().OnChange(profile => Console.WriteLine($"changed: {profile.Age}"));
Console.Read();
public class Profile
{
public int Age { get; set; }
}
"Options模型"與“配置系統”結合，
2. 將配置系結為Options物件
如下兩個demo分別演示了"Options模型"與“配置系統”結合的結合使用，
Demo1
var configuration = new ConfigurationBuilder ().AddJsonFile ("profile.json").Build ();
var profile = new ServiceCollection().AddOptions().Configure<Profile>(configuration).BuildServiceProvider().GetRequiredService<IOptions<Profile>>().Value;
Demo2
var source = new Dictionary<string, string>{
{"TestOptions:Key1" ,"TestOptions key1"},
{"TestOptions:Key2" ,"TestOptions key2"},
{"UserInfo:key1" ,"UserInfo"},
};
var config = new ConfigurationBuilder().Add(new MemoryConfigurationSource() { InitialData = https://www.cnblogs.com/hts92/p/source }).Build();
ServiceCollection services = new ServiceCollection();
services.AddOptions();
services.Configure(config.GetSection("TestOptions")); // Import the "Microsoft.Extensions.Options.ConfigurationExtensions" package.
var serviceProvider = services.BuildServiceProvider();
var options = serviceProvider.GetRequiredService<IOptions<TestOpetion>>();
Console.WriteLine(options.Value.Key1);
Console.ReadLine();
public class TestOpetion{
public string Key1{ get; set; }
public string Key2 { get; set; }
}
以上操作步驟為OptionsConfigurationServiceCollectionExtensions類定義了對 Configure的擴展，有三個引數string name、config（IConfiguration），configureBinder的委托，第一個引數是TOptions的name， 第二個表示配置系統的IConfiguration，第三個configureBinder 是配置系統在映射Toptions時候的一些配置
原理很簡單，因為有了ServiceCollection的支持，那么就往里面幫我們注入一個型別為IConfigureOptions
關于configureBinder基本邏輯基本是根據TOptions的Type 物件反射出資訊，然后第二個引數config（配置系統提供資料的介面）拿資料，在把對應的資料系結在TOptions 物件上，
public static IServiceCollection Configure<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TOptions>(this IServiceCollection services!!, string? name, IConfiguration config!!, Action<BinderOptions>? configureBinder)
where TOptions : class
{
services.AddOptions();
// 用于支持**“配置系統”**與 **"Options模型"**結合后當配置系統發生更新時回呼options時注冊的回呼函式，后面會說到
services.AddSingleton<IOptionsChangeTokenSource<TOptions>>(new ConfigurationChangeTokenSource<TOptions>(name, config));
// 注冊NamedConfigureFromConfigurationOptions
return services.AddSingleton<IConfigureOptions<TOptions>>(new NamedConfigureFromConfigurationOptions<TOptions>(name, config, configureBinder));
}
/// Configures an option instance by using <see cref="ConfigurationBinder.Bind(IConfiguration, object)"/> against an <see cref="IConfiguration"/>.
public class NamedConfigureFromConfigurationOptions<TOptions> : ConfigureNamedOptions<TOptions> where TOptions : class
{
public NamedConfigureFromConfigurationOptions(string? name, IConfiguration config!!, Action<BinderOptions>? configureBinder)
: base(name, options => BindFromOptions(options, config, configureBinder)){
}
private static void BindFromOptions(TOptions options, IConfiguration config, Action<BinderOptions>? configureBinder) => config.Bind(options, configureBinder);
}
public class BinderOptions
{
// true 會對TOptons的私有屬性也賦值
public bool BindNonPublicProperties { get; set; }
public bool ErrorOnUnknownConfiguration { get; set; }
}
驗證Options的有效性
Options 擴展方法注冊Microsoft.Extensions.Options向Service容器注入認證服務，其原理是OptionsFactory.Create拿到所有注入的服務，將TOptons作為引數傳入實體的驗證方法，
services.AddOptions<DateTimeFormatOptions>().Configure(options =>options. DatePattern = datePattern;options.TimePattern = timePattern;).Validate(options => Validate (options.DatePattern) && Validate(options. TimePattern), "Invalid Date or Time pattern.");
其它
OptionsServiceCollectionExtensions Options 模型依賴的服務
public static IServiceCollection AddOptions(this IServiceCollection services)
{
services.TryAdd(ServiceDescriptor.Singleton(typeof(IOptions<>), typeof(UnnamedOptionsManager<>)));
services.TryAdd(ServiceDescriptor.Scoped(typeof(IOptionsSnapshot<>), typeof(OptionsManager<>)));
services.TryAdd(ServiceDescriptor.Singleton(typeof(IOptionsMonitor<>), typeof(OptionsMonitor<>)));
services.TryAdd(ServiceDescriptor.Transient(typeof(IOptionsFactory<>), typeof(OptionsFactory<>)));
services.TryAdd(ServiceDescriptor.Singleton(typeof(IOptionsMonitorCache<>), typeof(OptionsCache<>)));
}
文章中提到的代碼，請在source.dot.net快速搜索預覽
本文來自博客園，作者：一身大膘，轉載請注明原文鏈接：https://www.cnblogs.com/hts92/p/15927329.html
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