{
  "test": "lib"
}

{
  "test": "console"
}

├─Demo5.Console
│  │  Demo5.Console.csproj
│  │  Program.cs
│  │
│  ├─i18n
│  │  └─Demo5.Console
│  │          en-US.json
│  │          zh-CN.json
│
├─Demo5.Lib
│  │  Demo5.Lib.csproj
│  │  Extensions.cs
│  │
│  ├─i18n
│  │  └─Demo5.Lib
│  │          en-US.json
│  │          zh-CN.json

var ioc = new ServiceCollection();
ioc.AddI18n("zh-CN");
ioc.AddI18nResource(options =>
{
	options.ParseDirectory("i18n");
});
ioc.AddLib();
var services = ioc.BuildServiceProvider();
// 手動(dòng)設(shè)置當(dāng)前請(qǐng)求語言
using (var c = new I18nScope("en-US"))
{
	var l1 = services.GetRequiredService<IStringLocalizer<Program>>();
	var l2 = services.GetRequiredService<IStringLocalizer<Test>>();
	var s1 = l1["test"];
	var s2 = l2["test"];
	Console.WriteLine(s1);
	Console.WriteLine(s2);
}

.
├── Demo5.Console
│   ├── en-US.json
│   └── zh-CN.json
└── Demo5.Lib
    ├── en-US.json
    └── zh-CN.json

ioc.AddI18nResource(options =>
{
	options.AddJsonFile("zh-CN", "i18n/zh-CN.json");
	options.AddJsonFile("en-US", "i18n/en-US.json");
});

ioc.AddI18nResource(options =>
{
	options.AddJsonDirectory("i18n");
});

// 手動(dòng)設(shè)置當(dāng)前請(qǐng)求語言
using (var c = new I18nScope("en-US"))
{
	var l1 = services.GetRequiredService<IStringLocalizer>();
	var l2 = services.GetRequiredService<IStringLocalizer>();
	var s1 = l1["test"];
	var s2 = l2["test"];
	Console.WriteLine(s1);
	Console.WriteLine(s2);
}

CultureInfo.CurrentCulture = new CultureInfo("zh-CN");

public class MyI18nContext : I18nContext
{
    public MyI18nContext()
    {
        base.Culture = ...
    }
    public void Set(CultureInfo cultureInfo)
    {
        base.Culture = cultureInfo;
    }
}
builder.Services.AddScoped<I18nContext, MyI18nContext>();

{
  "購物車": {
    "商品名稱": "商品名稱",
    "加入時(shí)間": "加入時(shí)間",
    "清理失效商品": "清理失效商品"
  },
  "會(huì)員等級(jí)": {
    "用戶名": "用戶名",
    "積分": "積分:{0}",
    "等級(jí)": "等級(jí)"
  }
}

{
  "購物車": {
    "商品名稱": "Product name",
    "加入時(shí)間": "Join date",
    "清理失效商品": "Cleaning up failures"
  },
  "會(huì)員等級(jí)": {
    "用戶名": "Username",
    "積分": "Member points:{0}",
    "等級(jí)": "Level"
  }
}

// 添加 i18n 多語言支持
builder.Services.AddI18nAspNetCore(defaultLanguage: "zh-CN");
// 設(shè)置多語言來源-json
builder.Services.AddI18nResource(option =>
{
    var basePath = "i18n";
    option.AddJson(basePath);
});

var app = builder.Build();
app.UseI18n();	// <- 放到中間件靠前的位置

app.UseRouting();
app.Use(async (HttpContext context, RequestDelegate next) =>
{
	var localizer = context.RequestServices.GetRequiredService<IStringLocalizer<Program>>();
	await context.Response.WriteAsync(localizer["購物車:商品名稱"]);
	return;
});

?culture=en-US&ui-culture=en-US

c=en-US|uic=en-US

.AspNetCore.Culture=c=en-US|uic=en-US

Accept-Language: zh-CN,zh;q=0.9

new QueryStringRequestCultureProvider()
{
	QueryStringKey = "lan",
	UIQueryStringKey = "ui"
}

var requestCultureFeature = context.Features.Get<IRequestCultureFeature>();
var requestCulture = requestCultureFeature?.RequestCulture;

// 自定義請(qǐng)求語言提供器
	// 或直接繼承 RequestCultureProvider
	public class I18nRequestCultureProvider : IRequestCultureProvider
	{
		private readonly string _defaultLanguage;
		public I18nRequestCultureProvider(string defaultLanguage)
		{
			_defaultLanguage = defaultLanguage;
		}
		private const string RouteValueKey = "c";
		private const string UIRouteValueKey = "uic";
		public override Task<ProviderCultureResult> DetermineProviderCultureResult(HttpContext  httpContext)
		{
			var request = httpContext.Request;
			if (!request.RouteValues.Any())
			{
				return NullProviderCultureResult;
			}
			string? queryCulture = null;
			string? queryUICulture = null;
			// 從路由中解析
			if (!string.IsNullOrWhiteSpace(RouteValueKey))
			{
				queryCulture = request.RouteValues[RouteValueKey]?.ToString();
			}
            // 其他過程省略
			var providerResultCulture = new ProviderCultureResult(queryCulture, queryUICulture);
			return Task.FromResult<ProviderCultureResult?>(providerResultCulture);
		}
	}

			services.Configure<RequestLocalizationOptions>(options =>
			{
				// 默認(rèn)自帶了三個(gè)請(qǐng)求語言提供器，會(huì)先從這些提供器識(shí)別要使用的語言。
				// QueryStringRequestCultureProvider
				// CookieRequestCultureProvider
				// AcceptLanguageHeaderRequestCultureProvider
				// 自定義請(qǐng)求請(qǐng)求語言提供器
				options.RequestCultureProviders.Add(new I18nRequestCultureProvider(defaultLanguage));
			});

// 當(dāng)前程序多語言上下文
I18nContext.cs
// 多語言資源接口定義
I18nResource.cs
// i18n 語言資源工廠
I18nResourceFactory.cs
// 設(shè)置當(dāng)前語言作用域
I18nScope.cs
// 服務(wù)注入擴(kuò)展
I18nExtensions.cs
// 從 json 文件讀取多語言資源擴(kuò)展
JsonResourceExtensions.cs
// 實(shí)現(xiàn) I18nResourceFactory
InternalI18nResourceFactory.cs
// 自定義請(qǐng)求語言解析
I18nRequestCultureProvider.cs
// 實(shí)現(xiàn) IStringLocalizer 接口
I18nStringLocalizer.cs
// 實(shí)現(xiàn) IStringLocalizer<T> 接口
I18nStringLocalizer`.cs
// 實(shí)現(xiàn) I18nResource，通過 json 文件導(dǎo)入語言資源
JsonResource.cs
// 解析 json 的幫助類
ReadJsonHelper.cs

/// <summary>
/// i18n 語言資源.
/// </summary>
/// <remarks>每個(gè) I18nResource 對(duì)應(yīng)一種語言的一個(gè)資源文件.</remarks>
public interface I18nResource
{
    /// <summary>
    /// 該資源提供的語言.
    /// </summary>
    CultureInfo SupportedCulture { get; }
    /// <summary>
    /// 獲取具有給定名稱的字符串資源.
    /// </summary>
    /// <param name="culture">語言名字.</param>
    /// <param name="name">字符串名稱.</param>
    /// <returns><see cref="LocalizedString"/>.</returns>
    LocalizedString Get(string culture, string name);
    /// <summary>
    /// 獲取具有給定名稱的字符串資源.
    /// </summary>
    /// <param name="culture">語言名字.</param>
    /// <param name="name">字符串名稱.</param>
    /// <param name="arguments">字符串插值參數(shù).</param>
    /// <returns><see cref="LocalizedString"/>.</returns>
    LocalizedString Get(string culture, string name, params object[] arguments);
    /// <summary>
    /// 從 i18n 資源文件中獲取所有字符串.
    /// </summary>
    /// <param name="includeParentCultures"></param>
    /// <returns><see cref="LocalizedString"/>.</returns>
    public IEnumerable<LocalizedString> GetAllStrings(bool includeParentCultures);
}
/// <summary>
/// i18n 語言資源.
/// </summary>
/// <remarks>每個(gè) I18nResource 對(duì)應(yīng)一種語言的一個(gè)資源文件.</remarks>
/// <typeparam name="T">類型.</typeparam>
public interface I18nResource<T> : I18nResource
{
}

/// <summary>
/// I18n 資源工廠.
/// </summary>
public interface I18nResourceFactory
{
    /// <summary>
    /// 當(dāng)前支持的語言.
    /// </summary>
    IList<CultureInfo> SupportedCultures { get; }
    /// <summary>
    /// 所有資源提供器.
    /// </summary>
    IList<I18nResource> Resources { get; }
    /// <summary>
    /// 在容器中的資源服務(wù).
    /// </summary>
    IList<Type> ServiceResources { get; }
    /// <summary>
    /// 添加 i18n 語言資源，該類型將會(huì)被從容器中取出.
    /// </summary>
    /// <param name="resourceType">i18n 語言資源.</param>
    /// <returns><see cref="I18nResourceFactory"/>.</returns>
    I18nResourceFactory AddServiceType(Type resourceType);
    /// <summary>
    /// 添加 i18n 語言資源.
    /// </summary>
    /// <param name="resource">i18n 語言資源.</param>
    /// <returns><see cref="I18nResourceFactory"/>.</returns>
    I18nResourceFactory Add(I18nResource resource);
    /// <summary>
    /// 添加 i18n 語言資源.
    /// </summary>
    /// <typeparam name="T">類型.</typeparam>
    /// <param name="resource">i18n 語言資源.</param>
    /// <returns><see cref="I18nResourceFactory"/>.</returns>
    I18nResourceFactory Add<T>(I18nResource<T> resource);
}

// 記錄當(dāng)前請(qǐng)求的 i18n 信息
public class I18nContext
{
	// 當(dāng)前用戶請(qǐng)求的語言
	public CultureInfo Culture { get; internal set; } = CultureInfo.CurrentCulture;
}

/// <summary>
/// 表示提供本地化字符串的服務(wù).
/// </summary>
public class I18nStringLocalizer : IStringLocalizer
{
    private readonly IServiceProvider _serviceProvider;
    private readonly I18nContext _context;
    private readonly I18nResourceFactory _resourceFactory;
    /// <summary>
    /// Initializes a new instance of the <see cref="I18nStringLocalizer"/> class.
    /// </summary>
    /// <param name="context"></param>
    /// <param name="resourceFactory"></param>
    /// <param name="serviceProvider"></param>
    public I18nStringLocalizer(I18nContext context, I18nResourceFactory resourceFactory, IServiceProvider serviceProvider)
    {
        _context = context;
        _resourceFactory = resourceFactory;
        _serviceProvider = serviceProvider;
    }
    /// <inheritdoc/>
    public LocalizedString this[string name] => Find(name);
    /// <inheritdoc/>
    public LocalizedString this[string name, params object[] arguments] => Find(name, arguments);
    /// <inheritdoc/>
    public IEnumerable<LocalizedString> GetAllStrings(bool includeParentCultures)
    {
        foreach (var serviceType in _resourceFactory.ServiceResources)
        {
            var resource = _serviceProvider.GetRequiredService(serviceType) as I18nResource;
            if (resource == null)
            {
                continue;
            }
            foreach (var item in resource.GetAllStrings(includeParentCultures))
            {
                yield return item;
            }
        }
        foreach (var resource in _resourceFactory.Resources)
        {
            foreach (var item in resource.GetAllStrings(includeParentCultures))
            {
                yield return item;
            }
        }
    }
    private LocalizedString Find(string name)
    {
        foreach (var serviceType in _resourceFactory.ServiceResources)
        {
            var resource = _serviceProvider.GetRequiredService(serviceType) as I18nResource;
            if (resource == null)
            {
                continue;
            }
            if (_context.Culture.Name != resource.SupportedCulture.Name)
            {
                continue;
            }
            var result = resource.Get(_context.Culture.Name, name);
            if (result == null || result.ResourceNotFound)
            {
                continue;
            }
            return result;
        }
        foreach (var resource in _resourceFactory.Resources)
        {
            if (_context.Culture.Name != resource.SupportedCulture.Name)
            {
                continue;
            }
            var result = resource.Get(_context.Culture.Name, name);
            if (result == null || result.ResourceNotFound)
            {
                continue;
            }
            return result;
        }
        // 所有的資源都查找不到時(shí)，使用默認(rèn)值
        return new LocalizedString(name, name);
    }
    private LocalizedString Find(string name, params object[] arguments)
    {
        foreach (var serviceType in _resourceFactory.ServiceResources)
        {
            var resource = _serviceProvider.GetRequiredService(serviceType) as I18nResource;
            if (resource == null)
            {
                continue;
            }
            if (_context.Culture.Name != resource.SupportedCulture.Name)
            {
                continue;
            }
            var result = resource.Get(_context.Culture.Name, name, arguments);
            if (result == null || result.ResourceNotFound)
            {
                continue;
            }
            return result;
        }
        foreach (var resource in _resourceFactory.Resources)
        {
            if (_context.Culture.Name != resource.SupportedCulture.Name)
            {
                continue;
            }
            var result = resource.Get(_context.Culture.Name, name, arguments);
            if (result == null || result.ResourceNotFound)
            {
                continue;
            }
            return result;
        }
        // 所有的資源都查找不到時(shí)，使用默認(rèn)值
        return new LocalizedString(name, string.Format(name, arguments));
    }
}

/// <summary>
/// 表示提供本地化字符串的服務(wù).
/// </summary>
/// <typeparam name="T">類型.</typeparam>
public class I18nStringLocalizer<T> : IStringLocalizer<T>
{
    private readonly IServiceProvider _serviceProvider;
    private readonly I18nContext _context;
    private readonly I18nResourceFactory _resourceFactory;
    /// <summary>
    /// Initializes a new instance of the <see cref="I18nStringLocalizer{T}"/> class.
    /// </summary>
    /// <param name="context"></param>
    /// <param name="resourceFactory"></param>
    /// <param name="serviceProvider"></param>
    public I18nStringLocalizer(I18nContext context, I18nResourceFactory resourceFactory, IServiceProvider serviceProvider)
    {
        _context = context;
        _resourceFactory = resourceFactory;
        _serviceProvider = serviceProvider;
    }
    /// <inheritdoc/>
    public LocalizedString this[string name] => Find(name);
    /// <inheritdoc/>
    public LocalizedString this[string name, params object[] arguments] => Find(name, arguments);
    /// <inheritdoc/>
    public IEnumerable<LocalizedString> GetAllStrings(bool includeParentCultures)
    {
        foreach (var serviceType in _resourceFactory.ServiceResources)
        {
            var resource = _serviceProvider.GetRequiredService(serviceType) as I18nResource;
            if (resource == null)
            {
                continue;
            }
            foreach (var item in resource.GetAllStrings(includeParentCultures))
            {
                yield return item;
            }
        }
        foreach (var resource in _resourceFactory.Resources)
        {
            foreach (var item in resource.GetAllStrings(includeParentCultures))
            {
                yield return item;
            }
        }
    }
    private LocalizedString Find(string name)
    {
        var resourceType = typeof(I18nResource<T>);
        foreach (var serviceType in _resourceFactory.ServiceResources)
        {
            if (!serviceType.IsGenericType && serviceType.GenericTypeArguments[0].Assembly != typeof(T).Assembly)
            {
                continue;
            }
            var resource = _serviceProvider.GetRequiredService(serviceType) as I18nResource;
            if (resource == null)
            {
                continue;
            }
            if (_context.Culture.Name != resource.SupportedCulture.Name)
            {
                continue;
            }
            var result = resource.Get(_context.Culture.Name, name);
            if (result == null || result.ResourceNotFound)
            {
                continue;
            }
            return result;
        }
        foreach (var resource in _resourceFactory.Resources)
        {
            if (_context.Culture.Name != resource.SupportedCulture.Name)
            {
                continue;
            }
            // I18nResource<T>
            if (!resource.GetType().IsGenericType || resource.GetType().GenericTypeArguments[0].Assembly != typeof(T).Assembly)
            {
                continue;
            }
            var result = resource.Get(_context.Culture.Name, name);
            if (result == null || result.ResourceNotFound)
            {
                continue;
            }
            return result;
        }
        // 所有的資源都查找不到時(shí)，使用默認(rèn)值
        return new LocalizedString(name, name);
    }
    private LocalizedString Find(string name, params object[] arguments)
    {
        var resourceType = typeof(I18nResource<T>);
        foreach (var serviceType in _resourceFactory.ServiceResources)
        {
            if (!serviceType.IsGenericType && serviceType.GenericTypeArguments[0].Assembly != typeof(T).Assembly)
            {
                continue;
            }
            var resource = _serviceProvider.GetRequiredService(serviceType) as I18nResource;
            if (resource == null)
            {
                continue;
            }
            if (_context.Culture.Name != resource.SupportedCulture.Name)
            {
                continue;
            }
            var result = resource.Get(_context.Culture.Name, name, arguments);
            if (result == null || result.ResourceNotFound)
            {
                continue;
            }
            return result;
        }
        foreach (var resource in _resourceFactory.Resources)
        {
            if (_context.Culture.Name != resource.SupportedCulture.Name)
            {
                continue;
            }
            // I18nResource<T>
            if (!resource.GetType().IsGenericType || resource.GetType().GenericTypeArguments[0].Assembly != typeof(T).Assembly)
            {
                continue;
            }
            var result = resource.Get(_context.Culture.Name, name, arguments);
            if (result == null || result.ResourceNotFound)
            {
                continue;
            }
            return result;
        }
        // 所有的資源都查找不到時(shí)，使用默認(rèn)值
        return new LocalizedString(name, string.Format(name, arguments));
    }
}

/// <summary>
/// i18n 作用域.
/// </summary>
public class I18nScope : IDisposable
{
    private readonly CultureInfo _defaultCultureInfo;
    /// <summary>
    /// Initializes a new instance of the <see cref="I18nScope"/> class.
    /// </summary>
    /// <param name="language"></param>
    public I18nScope(string language)
    {
        _defaultCultureInfo = CultureInfo.CurrentCulture;
        CultureInfo.CurrentCulture = CultureInfo.CreateSpecificCulture(language);
    }
    /// <inheritdoc/>
    public void Dispose()
    {
        CultureInfo.CurrentCulture = _defaultCultureInfo;
    }
}

/// <summary>
/// 字典存儲(chǔ)多語言文件資源.
/// </summary>
public class DictionaryResource : I18nResource
{
    /// <inheritdoc/>
    public CultureInfo SupportedCulture => _cultureInfo;
    private readonly CultureInfo _cultureInfo;
    private readonly IReadOnlyDictionary<string, LocalizedString> _kvs;
    /// <summary>
    /// Initializes a new instance of the <see cref="DictionaryResource"/> class.
    /// </summary>
    /// <param name="cultureInfo"></param>
    /// <param name="kvs"></param>
    public DictionaryResource(CultureInfo cultureInfo, IReadOnlyDictionary<string, object> kvs)
    {
        _cultureInfo = cultureInfo;
        _kvs = kvs.ToDictionary(x => x.Key, x => new LocalizedString(x.Key, x.Value.ToString()!));
    }
    /// <inheritdoc/>
    public virtual LocalizedString Get(string culture, string name)
    {
        if (culture != _cultureInfo.Name)
        {
            return new LocalizedString(name, name, resourceNotFound: true);
        }
        var value = _kvs.GetValueOrDefault(name);
        if (value == null)
        {
            return new LocalizedString(name, name, resourceNotFound: true);
        }
        return value;
    }
    /// <inheritdoc/>
    public virtual LocalizedString Get(string culture, string name, params object[] arguments)
    {
        if (culture != _cultureInfo.Name)
        {
            return new LocalizedString(name, name, resourceNotFound: true);
        }
        var value = _kvs.GetValueOrDefault(name);
        if (value == null)
        {
            return new LocalizedString(name, name, resourceNotFound: true);
        }
        return new LocalizedString(name, string.Format(value, arguments));
    }
    /// <inheritdoc/>
    public virtual IEnumerable<LocalizedString> GetAllStrings(bool includeParentCultures)
    {
        return _kvs.Values;
    }
}

/// <summary>
/// 字典存儲(chǔ)多語言文件資源.
/// </summary>
/// <typeparam name="TResource">類型.</typeparam>
public class DictionaryResource<TResource> : DictionaryResource, I18nResource<TResource>
{
    private readonly Assembly _assembly;
    /// <summary>
    /// Initializes a new instance of the <see cref="DictionaryResource{TResource}"/> class.
    /// </summary>
    /// <param name="cultureInfo"></param>
    /// <param name="kvs"></param>
    /// <param name="assembly"></param>
    public DictionaryResource(CultureInfo cultureInfo, IReadOnlyDictionary<string, object> kvs, Assembly assembly)
        : base(cultureInfo, kvs)
    {
        _assembly = assembly;
    }
    /// <inheritdoc/>
    public override LocalizedString Get(string culture, string name)
    {
        if (typeof(TResource).Assembly != _assembly)
        {
            return new LocalizedString(name, name, resourceNotFound: true);
        }
        return base.Get(culture, name);
    }
    /// <inheritdoc/>
    public override LocalizedString Get(string culture, string name, params object[] arguments)
    {
        if (typeof(TResource).Assembly != _assembly)
        {
            return new LocalizedString(name, name, resourceNotFound: true);
        }
        return base.Get(culture, name, arguments);
    }
}

/// <summary>
/// Json 多語言文件資源.
/// </summary>
public static class JsonResourceExtensions
{
    /// <summary>
    /// 掃描目錄下的所有子目錄，自動(dòng)區(qū)配對(duì)應(yīng)的項(xiàng)目/程序集下，json 文件名稱會(huì)被動(dòng)作語言名稱.
    /// </summary>
    /// <param name="resourceFactory"></param>
    /// <param name="basePath"></param>
    /// <returns><see cref="I18nResourceFactory"/>.</returns>
    public static I18nResourceFactory ParseDirectory(
        this I18nResourceFactory resourceFactory,
        string basePath)
    {
        var basePathDirectoryInfo = new DirectoryInfo(basePath);
        Queue<DirectoryInfo> directoryInfos = new Queue<DirectoryInfo>();
        var assemblies = AppDomain.CurrentDomain.GetAssemblies();
        var basePathFullName = basePathDirectoryInfo.FullName;
        directoryInfos.Enqueue(basePathDirectoryInfo);
        while (directoryInfos.Count > 0)
        {
            var curDirectory = directoryInfos.Dequeue();
            var lanDir = curDirectory.GetDirectories();
            foreach (var lan in lanDir)
            {
                directoryInfos.Enqueue(lan);
            }
            var files = curDirectory.GetFiles().Where(x => x.Name.EndsWith(".json")).ToArray();
            if (files.Length == 0)
            {
                continue;
            }
            // 移除路徑的前部分
            var curPath = curDirectory.FullName[basePathFullName.Length..].Trim('/', '\\');
            var assembly = assemblies.FirstOrDefault(x => string.Equals(curPath, x.GetName().Name, StringComparison.CurrentCultureIgnoreCase));
            if (assembly == null)
            {
                continue;
            }
            foreach (var file in files)
            {
                var language = Path.GetFileNameWithoutExtension(file.Name);
                var text = File.ReadAllText(file.FullName);
                var dic = ReadJsonHelper.Read(new ReadOnlySequence<byte>(Encoding.UTF8.GetBytes(text)), new JsonReaderOptions { AllowTrailingCommas = true });
                DictionaryResource jsonResource = (Activator.CreateInstance(
                    typeof(DictionaryResource<>).MakeGenericType(assembly.GetTypes()[0]),
                    new object[] { new CultureInfo(language), dic, assembly }) as DictionaryResource)!;
                resourceFactory.Add(jsonResource);
            }
        }
        return resourceFactory;
    }
    /// <summary>
    /// 添加 json 文件資源，json 文件名稱會(huì)被當(dāng)作語言名稱.
    /// </summary>
    /// <param name="resourceFactory"></param>
    /// <param name="basePath">基礎(chǔ)路徑.</param>
    /// <returns><see cref="I18nResourceFactory"/>.</returns>
    public static I18nResourceFactory AddJsonDirectory(
        this I18nResourceFactory resourceFactory,
        string basePath)
    {
        var rootDir = new DirectoryInfo(basePath);
        var files = rootDir.GetFiles().Where(x => x.Name.EndsWith(".json"));
        foreach (var file in files)
        {
            var language = Path.GetFileNameWithoutExtension(file.Name);
            var text = File.ReadAllText(file.FullName);
            var dic = ReadJsonHelper.Read(new ReadOnlySequence<byte>(Encoding.UTF8.GetBytes(text)), new JsonReaderOptions { AllowTrailingCommas = true });
            DictionaryResource jsonResource = new DictionaryResource(new CultureInfo(language), dic);
            resourceFactory.Add(jsonResource);
        }
        return resourceFactory;
    }
    /// <summary>
    /// 添加 json 文件資源，將目錄下的所有 json 文件都?xì)w類到此程序集下，json 文件名稱會(huì)被當(dāng)作語言名稱.
    /// </summary>
    /// <typeparam name="T">類型.</typeparam>
    /// <param name="resourceFactory"></param>
    /// <param name="basePath">基礎(chǔ)路徑.</param>
    /// <returns><see cref="I18nResourceFactory"/>.</returns>
    public static I18nResourceFactory AddJsonDirectory<T>(
        this I18nResourceFactory resourceFactory,
        string basePath)
        where T : class
    {
        var rootDir = new DirectoryInfo(basePath);
        var files = rootDir.GetFiles().Where(x => x.Name.EndsWith(".json"));
        foreach (var file in files)
        {
            var language = Path.GetFileNameWithoutExtension(file.Name);
            var text = File.ReadAllText(file.FullName);
            var dic = ReadJsonHelper.Read(new ReadOnlySequence<byte>(Encoding.UTF8.GetBytes(text)), new JsonReaderOptions { AllowTrailingCommas = true });
            DictionaryResource<T> jsonResource = new DictionaryResource<T>(new CultureInfo(language), dic, typeof(T).Assembly);
            resourceFactory.Add(jsonResource);
        }
        return resourceFactory;
    }
    /// <summary>
    /// 添加 json 文件資源.
    /// </summary>
    /// <param name="resourceFactory"></param>
    /// <param name="language">語言.</param>
    /// <param name="jsonFile">json 文件路徑.</param>
    /// <returns><see cref="I18nResourceFactory"/>.</returns>
    public static I18nResourceFactory AddJsonFile(this I18nResourceFactory resourceFactory, string language, string jsonFile)
    {
        string s = File.ReadAllText(jsonFile);
        Dictionary<string, object> kvs = ReadJsonHelper.Read(new ReadOnlySequence<byte>(Encoding.UTF8.GetBytes(s)), new JsonReaderOptions
        {
            AllowTrailingCommas = true
        });
        DictionaryResource resource = new DictionaryResource(new CultureInfo(language), kvs);
        resourceFactory.Add(resource);
        return resourceFactory;
    }
    /// <summary>
    /// 添加 json 文件資源.
    /// </summary>
    /// <typeparam name="T">類型.</typeparam>
    /// <param name="resourceFactory"></param>
    /// <param name="language">語言.</param>
    /// <param name="jsonFile">json 文件路徑.</param>
    /// <returns><see cref="I18nResourceFactory"/>.</returns>
    public static I18nResourceFactory AddJsonFile<T>(this I18nResourceFactory resourceFactory, string language, string jsonFile)
        where T : class
    {
        string s = File.ReadAllText(jsonFile);
        Dictionary<string, object> kvs = ReadJsonHelper.Read(new ReadOnlySequence<byte>(Encoding.UTF8.GetBytes(s)), new JsonReaderOptions
        {
            AllowTrailingCommas = true
        });
        DictionaryResource<T> resource = new DictionaryResource<T>(new CultureInfo(language), kvs, typeof(T).Assembly);
        resourceFactory.Add(resource);
        return resourceFactory;
    }
}

/// <summary>
/// i18n 語言資源管理器.
/// </summary>
public class InternalI18nResourceFactory : I18nResourceFactory
{
    private readonly List<CultureInfo> _supportedCultures;
    private readonly List<I18nResource> _resources;
    private readonly List<Type> _serviceResources;
    /// <summary>
    /// Initializes a new instance of the <see cref="InternalI18nResourceFactory"/> class.
    /// </summary>
    public InternalI18nResourceFactory()
    {
        _supportedCultures = new();
        _resources = new();
        _serviceResources = new();
    }
    /// <inheritdoc/>
    public IList<CultureInfo> SupportedCultures => _supportedCultures;
    /// <inheritdoc/>
    public IList<I18nResource> Resources => _resources;
    /// <inheritdoc/>
    public IList<Type> ServiceResources => _serviceResources;
    /// <inheritdoc/>
    public I18nResourceFactory Add(I18nResource resource)
    {
        _supportedCultures.Add(resource.SupportedCulture);
        _resources.Add(resource);
        return this;
    }
    /// <inheritdoc/>
    public I18nResourceFactory Add<T>(I18nResource<T> resource)
    {
        _supportedCultures.Add(resource.SupportedCulture);
        _resources.Add(resource);
        return this;
    }
    /// <inheritdoc/>
    public I18nResourceFactory AddServiceType(Type resourceType)
    {
        _serviceResources.Add(resourceType);
        return this;
    }
}

/// <summary>
/// 表示創(chuàng)建<see cref="IStringLocalizer"/> 實(shí)例的工廠.
/// </summary>
public class I18nStringLocalizerFactory : IStringLocalizerFactory
{
    private readonly I18nResourceFactory _i18nResourceFactory;
    private readonly IServiceProvider _serviceProvider;
    /// <summary>
    /// Initializes a new instance of the <see cref="I18nStringLocalizerFactory"/> class.
    /// </summary>
    /// <param name="i18nResourceFactory"></param>
    /// <param name="serviceProvider"></param>
    public I18nStringLocalizerFactory(I18nResourceFactory i18nResourceFactory, IServiceProvider serviceProvider)
    {
        _i18nResourceFactory = i18nResourceFactory;
        _serviceProvider = serviceProvider;
    }
    /// <inheritdoc/>
    public IStringLocalizer Create(Type resourceSource)
    {
        var type = typeof(I18nStringLocalizer<>).MakeGenericType(resourceSource);
        return (_serviceProvider.GetRequiredService(type) as IStringLocalizer)!;
    }
    /// <inheritdoc/>
    public IStringLocalizer Create(string baseName, string location)
    {
        return _serviceProvider.GetRequiredService<IStringLocalizer>();
    }
}

/// <summary>
/// i18n 擴(kuò)展.
/// </summary>
public static class I18nExtensions
{
    /// <summary>
    /// 添加 i18n 支持服務(wù).
    /// </summary>
    /// <param name="services"></param>
    /// <param name="defaultLanguage">默認(rèn)語言.</param>
    public static void AddI18n(this IServiceCollection services, string defaultLanguage = "zh-CN")
    {
        InternalI18nResourceFactory resourceFactory = new InternalI18nResourceFactory();
        // i18n 上下文
        services.AddScoped<I18nContext, DefaultI18nContext>();
        // 注入 i18n 服務(wù)
        services.AddSingleton<I18nResourceFactory>(s => resourceFactory);
        services.AddScoped<IStringLocalizerFactory, I18nStringLocalizerFactory>();
        services.AddScoped<IStringLocalizer, I18nStringLocalizer>();
        services.TryAddEnumerable(new ServiceDescriptor(typeof(IStringLocalizer<>), typeof(I18nStringLocalizer<>), ServiceLifetime.Scoped));
    }
    /// <summary>
    /// 添加 i18n 資源.
    /// </summary>
    /// <param name="services"></param>
    /// <param name="resourceFactory"></param>
    public static void AddI18nResource(this IServiceCollection services, Action<I18nResourceFactory> resourceFactory)
    {
        var service = services.BuildServiceProvider().GetRequiredService<I18nResourceFactory>();
        resourceFactory.Invoke(service);
    }
}

/// <summary>
/// i18n 擴(kuò)展.
/// </summary>
public static class I18nExtensions
{
    /// <summary>
    /// 添加 i18n 支持服務(wù).
    /// </summary>
    /// <param name="services"></param>
    /// <param name="defaultLanguage">默認(rèn)語言.</param>
    public static void AddI18nAspNetCore(this IServiceCollection services, string defaultLanguage = "zh-CN")
    {
        services.AddI18n(defaultLanguage);
        var resourceFactory = services.BuildServiceProvider().GetRequiredService<I18nResourceFactory>();
        // ASP.NET Core 自帶的
        services.AddLocalization();
        // 配置 ASP.NET Core 的本地化服務(wù)
        services.Configure<RequestLocalizationOptions>(options =>
        {
            options.ApplyCurrentCultureToResponseHeaders = true;
            options.DefaultRequestCulture = new RequestCulture(culture: defaultLanguage, uiCulture: defaultLanguage);
            options.SupportedCultures = resourceFactory.SupportedCultures;
            options.SupportedUICultures = resourceFactory.SupportedCultures;
            // 默認(rèn)自帶了三個(gè)請(qǐng)求語言提供器，會(huì)先從這些提供器識(shí)別要使用的語言。
            // QueryStringRequestCultureProvider
            // CookieRequestCultureProvider
            // AcceptLanguageHeaderRequestCultureProvider
            // 自定義請(qǐng)求請(qǐng)求語言提供器
            options.RequestCultureProviders.Add(new InternalRequestCultureProvider(options));
        });
        // i18n 上下文
        services.AddScoped<I18nContext, HttpI18nContext>();
    }
    /// <summary>
    /// i18n 中間件.
    /// </summary>
    /// <param name="app"></param>
    public static void UseI18n(this IApplicationBuilder app)
    {
        var options = app.ApplicationServices.GetRequiredService<IOptions<RequestLocalizationOptions>>();
        app.UseRequestLocalization(options.Value);
    }
}

/// <summary>
/// 模型驗(yàn)證使用多語言.
/// </summary>
public static partial class DataAnnotationsExtensions
{
    /// <summary>
    /// 為 API 模型驗(yàn)證注入 i18n 服務(wù).
    /// </summary>
    /// <param name="builder"></param>
    /// <returns><see cref="IMvcBuilder"/>.</returns>
    public static IMvcBuilder AddI18nDataAnnotation(this IMvcBuilder builder)
    {
        builder
            .AddDataAnnotationsLocalization(options =>
            {
                options.DataAnnotationLocalizerProvider = (modelType, stringLocalizerFactory) =>
                stringLocalizerFactory.Create(modelType);
            });
        return builder;
    }
}

[Fact]
public async Task I18n_Request()
{    
}

using var host = await new HostBuilder()
	.ConfigureWebHost(webBuilder =>
	{
		webBuilder
			.UseTestServer()
			.ConfigureServices(services =>
			{
				services.AddControllers();
				services.AddI18n(defaultLanguage: "zh-CN");
				services.AddI18nResource(option =>
				{
					var basePath = "i18n";
					option.AddJson(basePath);
				});
			})
			.Configure(app =>
			{
				app.UseI18n();
				app.UseRouting();
				app.Use(async (HttpContext context, RequestDelegate next) =>
				{
					var localizer = context.RequestServices.GetRequiredService<IStringLocalizer<Program>>();
					await context.Response.WriteAsync(localizer["購物車:商品名稱"]);
					return;
				});
			});
	})
	.StartAsync();

var httpClient = host.GetTestClient();

httpClient.DefaultRequestHeaders.AcceptLanguage.Clear();
var response = await httpClient.GetStringAsync("/test?culture=en-US&ui-culture=en-US");
Assert.Equal("Product name", response);
response = await httpClient.GetStringAsync("/test?culture=zh-CN&ui-culture=zh-CN");
Assert.Equal("商品名稱", response);
httpClient.DefaultRequestHeaders.Add("Cookie", ".AspNetCore.Culture=c=en-US|uic=en-US");
response = await httpClient.GetStringAsync("/test");
Assert.Equal("Product name", response);
httpClient.DefaultRequestHeaders.Add("Cookie", ".AspNetCore.Culture=c=zh-CN|uic=zh-CN");
response = await httpClient.GetStringAsync("/test");
Assert.Equal("商品名稱", response);
httpClient.DefaultRequestHeaders.Remove("Cookie");
httpClient.DefaultRequestHeaders.AcceptLanguage.Clear();
httpClient.DefaultRequestHeaders.AcceptLanguage.Add(new StringWithQualityHeaderValue("zh-CN"));
httpClient.DefaultRequestHeaders.AcceptLanguage.Add(new StringWithQualityHeaderValue("zh", 0.9));
response = await httpClient.GetStringAsync("/test");
Assert.Equal("商品名稱", response);
httpClient.DefaultRequestHeaders.AcceptLanguage.Clear();
httpClient.DefaultRequestHeaders.AcceptLanguage.Add(new StringWithQualityHeaderValue("en-US"));
httpClient.DefaultRequestHeaders.AcceptLanguage.Add(new StringWithQualityHeaderValue("en", 0.9));
response = await httpClient.GetStringAsync("/test");
Assert.Equal("Product name", response);
httpClient.DefaultRequestHeaders.AcceptLanguage.Clear();
httpClient.DefaultRequestHeaders.AcceptLanguage.Add(new StringWithQualityHeaderValue("sv"));
httpClient.DefaultRequestHeaders.AcceptLanguage.Add(new StringWithQualityHeaderValue("en-US", 0.9));
response = await httpClient.GetStringAsync("/test");
Assert.Equal("Product name", response);

// i18n redis 資源
public class RedisI18nResource : I18nResource
{
	private readonly RedisClient _redisClient;
	private readonly string _pathPrefix;
	internal RedisI18nResource(RedisClient redisClient, string pathPrefix, TimeSpan expired, int capacity = 10)
	{
		_redisClient = redisClient;
		_pathPrefix = pathPrefix;
		// Redis client-side 模式
		redisClient.UseClientSideCaching(new ClientSideCachingOptions
		{
			Capacity = capacity,
			KeyFilter = key => key.StartsWith(pathPrefix),
			CheckExpired = (key, dt) => DateTime.Now.Subtract(dt) > expired
		});
		// FreeRedis 的 client-side 模式，使用 Hash 類型時(shí)，
		// 第一次需要先 HGetAll() ，框架將緩存拉取到本地
		GetAllStrings(default);
	}
	public IReadOnlyList<CultureInfo> SupportedCultures => _redisClient
		.Keys(_pathPrefix)
		.Select(x => new CultureInfo(x.Remove(0, _pathPrefix.Length + 1))).ToList();
	public IReadOnlyList<CultureInfo> SupportedUICultures => _redisClient
		.Keys(_pathPrefix)
		.Select(x => new CultureInfo(x.Remove(0, _pathPrefix.Length + 1))).ToList();
	public LocalizedString Get(string culture, string name)
	{
		var key = $"{_pathPrefix}:{culture}";
		var value = _redisClient.HGet<string>(key, name);
		if (string.IsNullOrEmpty(value)) return new LocalizedString(name, name, resourceNotFound: true);
		return new LocalizedString(name, value);
	}
	public LocalizedString Get(string culture, string name, params object[] arguments)
	{
		var key = $"{_pathPrefix}:{culture}";
		var value = _redisClient.HGet<string>(key, name);
		if (string.IsNullOrEmpty(value)) return new LocalizedString(name, name, resourceNotFound: true);
		var v = string.Format(value, arguments);
		return new LocalizedString(name, v);
	}
	public LocalizedString Get<T>(string culture, string name)
	{
		var key = $"{_pathPrefix}:{culture}";
		var value = _redisClient.HGet<string>(key, name);
		if (string.IsNullOrEmpty(value)) return new LocalizedString(name, name, resourceNotFound: true);
		return new LocalizedString(name, value);
	}
	public LocalizedString Get<T>(string culture, string name, params object[] arguments)
	{
		var key = $"{_pathPrefix}:{culture}";
		var value = _redisClient.HGet<string>(key, name);
		if (string.IsNullOrEmpty(value)) return new LocalizedString(name, name, resourceNotFound: true);
		var v = string.Format(value, arguments);
		return new LocalizedString(name, v);
	}
	public IEnumerable<LocalizedString> GetAllStrings(bool includeParentCultures)
	{
		var keys = _redisClient.Keys(_pathPrefix);
		foreach (var key in keys)
		{
			var vs = _redisClient.HGetAll<string>(key);
			foreach (var item in vs)
			{
				yield return new LocalizedString(item.Key, item.Value);
			}
		}
	}
}

public static class Extensions
{
	// 添加 i18n redis 資源
	public static I18nResourceFactory AddRedis(this I18nResourceFactory resourceFactory,
		RedisClient.DatabaseHook redis,
		string pathPrefix,
		TimeSpan expired,
		int capacity = 10
		)
	{
		redis.UseClientSideCaching(new ClientSideCachingOptions
		{
			Capacity = capacity,
			KeyFilter = key => key.StartsWith(pathPrefix),
			CheckExpired = (key, dt) => DateTime.Now.Subtract(dt) > expired
		});
		var keys = redis.Keys(pathPrefix);
		resourceFactory.Add(new RedisI18nResource(redis, pathPrefix));
		return resourceFactory;
	}
}

WRedisClient cli = new RedisClient("127.0.0.1:6379,defaultDatabase=0");
builder.Services.AddI18n(defaultLanguage: "zh-CN");
builder.Services.AddI18nResource(option =>
{
	option.AddRedis(cli, "language", TimeSpan.FromMinutes(100), 10);
	option.AddJson<Program>("i18n");
});

<ItemGroup>
		<Content Include="i18n\Demo5.Nuget\en-US.json" Pack="true">
			<PackageCopyToOutput>true</PackageCopyToOutput>
			<CopyToOutputDirectory>Always</CopyToOutputDirectory>
			<PackagePath>contentFiles\any\any\i18n\Demo5.Nuget\en-US.json</PackagePath>
		</Content>
		<Content Include="i18n\Demo5.Nuget\zh-CN.json" Pack="true">
			<PackageCopyToOutput>true</PackageCopyToOutput>
			<CopyToOutputDirectory>Always</CopyToOutputDirectory>
			<PackagePath>contentFiles\any\any\i18n\Demo5.Nuget\zh-CN.json</PackagePath>
		</Content>
	</ItemGroup>

<EnableDefaultContentItems>false</EnableDefaultContentItems>