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【.Net Core】使用SQL本地化的ASP.NET CORE

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本文为Google翻译的 原文地址

本文介绍如何使用SQL数据库在ASP.NET Core中使用SQL本地化。 演示中的SQL本地化使用Entity Framework Core访问SQLite数据库。 可以将其配置为使用任何EF核心提供程序。

使用SQL本地化

要使用SQL本地化，需要将该库添加到project.json文件中的依赖项。 该库称为Localization.SqlLocalizer。

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"dependencies": {
    "Localization.SqlLocalizer": "2.0.0"
}

然后可以将其添加到Startup类的ConfigureServices方法中。 AddSqlLocalization方法要求在实体框架服务扩展中配置LocalizationModelContext类。 在此示例中，SQLite用作LocalizationModelContext上下文类的提供程序。 其余的本地化可以根据需要进行配置。 该示例支持en-US，de-CH，fr-CH，it-CH。

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public void ConfigureServices(IServiceCollection services)
{
    // services.AddLocalization(options => options.ResourcesPath = "Resources");
 
    // init database for localization
    var sqlConnectionString = Configuration["DbStringLocalizer:ConnectionString"];
 
    services.AddDbContext<LocalizationModelContext>(options =>
        options.UseSqlite(
            sqlConnectionString, 
            b => b.MigrationsAssembly("AspNet5Localization")
        )
    );
 
    // Requires that LocalizationModelContext is defined
    // services.AddSqlLocalization(options =>  options.UseTypeFullNames = true);
    services.AddSqlLocalization();
 
    services.AddMvc()
        .AddViewLocalization()
        .AddDataAnnotationsLocalization();
 
    services.AddScoped<LanguageActionFilter>();
 
    services.Configure<RequestLocalizationOptions>(
        options =>
            {
                var supportedCultures = new List<CultureInfo>
                {
                    new CultureInfo("en-US"),
                    new CultureInfo("de-CH"),
                    new CultureInfo("fr-CH"),
                    new CultureInfo("it-CH")
                };
 
                options.DefaultRequestCulture = new RequestCulture(culture: "en-US", uiCulture: "en-US");
                options.SupportedCultures = supportedCultures;
                options.SupportedUICultures = supportedCultures;
            });
}

还需要在Configure方法中添加本地化。

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public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    loggerFactory.AddConsole();
    loggerFactory.AddDebug();
 
    var locOptions = app.ApplicationServices.GetService<IOptions<RequestLocalizationOptions>>();
    app.UseRequestLocalization(locOptions.Value);
 
    app.UseStaticFiles();
 
    app.UseMvc();
}

现在需要创建数据库。 如果使用SQLite，则在 SqliteCreateLocalizationRecord.sql 文件中 提供创建sql脚本 。 如果使用其他数据库，则需要创建该数据库。 我没有提供迁移脚本。 可以使用SQLite Manager在Firefox中执行SQLite脚本。

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CREATE TABLE "LocalizationRecords" (
    "Id" INTEGER NOT NULL CONSTRAINT "PK_DataEventRecord" PRIMARY KEY AUTOINCREMENT,
    "Key" TEXT,
    "ResourceKey" TEXT,
    "Text" TEXT,
    "LocalizationCulture" TEXT,
    "UpdatedTimestamp" TEXT NOT NULL
)

该数据库现在应该存在。 我添加了一些基本的演示行。

SQL Localization的默认配置使用资源名称，然后使用资源密钥（如果遵循Microsoft的建议，则可能是默认语言文本），然后使用区域性。 这些属性中的每个属性在数据库中都有一个单独的字段。 如果找不到本地化，则返回搜索到的关键字。 这是一个未找到并返回到UI的本地化示例。

ASP.NET Core MVC控制器：

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using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Localization;
 
namespace AspNet5Localization.Controllers
{
 
    [ServiceFilter(typeof(LanguageActionFilter))]
    [Route("api/{culture}/[controller]")]
    public class AboutWithCultureInRouteController : Controller
    {
        // http://localhost:5000/api/it-CH/AboutWithCultureInRoute
        // http://localhost:5000/api/fr-CH/AboutWithCultureInRoute
 
        private readonly IStringLocalizer<SharedResource> _localizer;
 
 
        public AboutWithCultureInRouteController(IStringLocalizer<SharedResource> localizer)
        {
            _localizer = localizer;
        }
 
        [HttpGet]
        public string Get()
        {
            return _localizer["Name"];
        }
    }
}

使用的网址：

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http://localhost:5000/api/fr-CH/AboutWithCultureInRoute

结果：ResoureKey：SharedResource，Key：名称，本地化文化：fr-CH

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SharedResource.Name.fr-CH

这应该使查找和添加缺失的本地化变得容易。

配置SQL本地化

还可以将SQL Localization配置为使用不同的键在数据库中搜索本地化。 可以使用services.AddSqlLocalization并添加options参数在Startup类中进行配置。

SqlLocalizationOptions具有两个属性，UseTypeFullNames和UseOnlyPropertyNames。 如果UseOnlyPropertyNames为true，则在数据库中仅将属性名称用作带有ResourceKey全局键的键。 您还可以通过设置UseTypeFullNames将其配置为使用FullNames作为键。 如果设置了此名称，则数据库的ResourceKey属性中需要完整的类型名称。

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public class SqlLocalizationOptions
{
    /// <summary>
    /// If UseOnlyPropertyNames is false, this property can be used to define keys with full type names or just the name of the class
    /// </summary>
    public bool UseTypeFullNames { get; set; }
 
    /// <summary>
    /// This can be used to use only property names to find the keys
    /// </summary>
    public bool UseOnlyPropertyNames { get; set; }
}

在Startup类中使用选项的示例：

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var sqlConnectionString = Configuration["DbStringLocalizer:ConnectionString"];
 
services.AddEntityFramework()
     .AddSqlite()
     .AddDbContext<LocalizationModelContext>(
         options => options.UseSqlite(sqlConnectionString));
 
// Requires that LocalizationModelContext is defined
services.AddSqlLocalization(options =>  options.UseTypeFullNames = true);

用于HTTP请求的Controller：

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using System.Globalization;
using System.Threading;
 
namespace AspNet5Localization.Controllers
{
    using Microsoft.AspNetCore.Mvc;
    using Microsoft.AspNetCore.Mvc.Localization;
    using Microsoft.Extensions.Localization;
 
    [Route("api/[controller]")]
    public class AboutController : Controller
    {
        private readonly IStringLocalizer<SharedResource> _localizer;
        private readonly IStringLocalizer<AboutController> _aboutLocalizerizer;
 
        public AboutController(IStringLocalizer<SharedResource> localizer, IStringLocalizer<AboutController> aboutLocalizerizer)
        {
            _localizer = localizer;
            _aboutLocalizerizer = aboutLocalizerizer;
        }
 
        [HttpGet]
        public string Get()
        {
            // _localizer["Name"] 
            return _aboutLocalizerizer["AboutTitle"];
        }
    }
}

网址：

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http://localhost:5000/api/about?culture=it-CH

结果：从结果中可以看到，SQL本地化使用FullName搜索了本地化。 ResoureKey：AspNet5Localization.Controllers.AboutController，键：AboutTitle，LocalizationCulture：it-CH

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AspNet5Localization.Controllers.AboutController.AboutTitle.it-CH

SQL本地化详细

SQL本地化库使用扩展方法来提供其服务，该服务可在应用程序的Startup类中使用。 该库取决于Entity Framework Core。 任何数据库提供程序都可以用于此目的。

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using System;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Microsoft.Extensions.Localization;
 
namespace Microsoft.Extensions.DependencyInjection
{
    using global::Localization.SqlLocalizer;
    using global::Localization.SqlLocalizer.DbStringLocalizer;
 
    /// <summary>
    /// Extension methods for adding localization servics to the DI container.
    /// </summary>
    public static class SqlLocalizationServiceCollectionExtensions
    {
        /// <summary>
        /// Adds services required for application localization.
        /// </summary>
        /// <param name="services">The <see cref="IServiceCollection"/> to add the services to.</param>
        /// <returns>The <see cref="IServiceCollection"/>.</returns>
        public static IServiceCollection AddSqlLocalization(this IServiceCollection services)
        {
            if (services == null)
            {
                throw new ArgumentNullException(nameof(services));
            }
 
            return AddSqlLocalization(services, setupAction: null);
        }
 
        /// <summary>
        /// Adds services required for application localization.
        /// </summary>
        /// <param name="services">The <see cref="IServiceCollection"/> to add the services to.</param>
        /// <param name="setupAction">An action to configure the <see cref="LocalizationOptions"/>.</param>
        /// <returns>The <see cref="IServiceCollection"/>.</returns>
        public static IServiceCollection AddSqlLocalization(
            this IServiceCollection services,
            Action<SqlLocalizationOptions> setupAction)
        {
            if (services == null)
            {
                throw new ArgumentNullException(nameof(services));
            }
 
            services.TryAdd(new ServiceDescriptor(
                typeof(IStringLocalizerFactory),
                typeof(SqlStringLocalizerFactory),
                ServiceLifetime.Singleton));
            services.TryAdd(new ServiceDescriptor(
                typeof(IStringLocalizer),
                typeof(SqlStringLocalizer),
                ServiceLifetime.Singleton));
 
            if (setupAction != null)
            {
                services.Configure(setupAction);
            }
            return services;
        }
    }
}

SqlStringLocalizerFactory类实现IStringLocalizerFactory，该对象负责数据库访问。 该数据库仅用于每个资源的第一个请求。 这意味着此后会有更好的性能，但是新的翻译仅 在 应用程序重新启动后 才能读取 。

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namespace Localization.SqlLocalizer.DbStringLocalizer
{
    using System;
    using System.Collections.Concurrent;
    using System.Collections.Generic;
    using System.Linq;
    using Microsoft.Extensions.Localization;
    using Microsoft.Extensions.Options;
    using Microsoft.Extensions.PlatformAbstractions;
 
    public class SqlStringLocalizerFactory : IStringLocalizerFactory
    {
        private readonly LocalizationModelContext _context;
        private readonly ConcurrentDictionary<string, IStringLocalizer> _resourceLocalizations = new ConcurrentDictionary<string, IStringLocalizer>();
        private readonly IOptions<SqlLocalizationOptions> _options;
        private const string Global = "global";
 
        public SqlStringLocalizerFactory(
           LocalizationModelContext context,
           IApplicationEnvironment applicationEnvironment,
           IOptions<SqlLocalizationOptions> localizationOptions)
        {
            if (context == null)
            {
                throw new ArgumentNullException(nameof(LocalizationModelContext));
            }
 
            if (applicationEnvironment == null)
            {
                throw new ArgumentNullException(nameof(applicationEnvironment));
            }
 
            if (localizationOptions == null)
            {
                throw new ArgumentNullException(nameof(localizationOptions));
            }
 
            _options = localizationOptions;
            _context = context;
        }
 
        public IStringLocalizer Create(Type resourceSource)
        {
            SqlStringLocalizer sqlStringLocalizer;
 
            if (_options.Value.UseOnlyPropertyNames)
            {
                if (_resourceLocalizations.Keys.Contains(Global))
                {
                    return _resourceLocalizations[Global];
                }
 
                sqlStringLocalizer = new SqlStringLocalizer(GetAllFromDatabaseForResource(Global), Global);
                return _resourceLocalizations.GetOrAdd(Global, sqlStringLocalizer);
                 
            }
 
            if (_options.Value.UseTypeFullNames)
            {
                if (_resourceLocalizations.Keys.Contains(resourceSource.FullName))
                {
                    return _resourceLocalizations[resourceSource.FullName];
                }
 
                sqlStringLocalizer = new SqlStringLocalizer(GetAllFromDatabaseForResource(resourceSource.FullName), resourceSource.FullName);
                _resourceLocalizations.GetOrAdd(resourceSource.FullName, sqlStringLocalizer);
            }
 
 
            if (_resourceLocalizations.Keys.Contains(resourceSource.Name))
            {
                return _resourceLocalizations[resourceSource.Name];
            }
 
            sqlStringLocalizer = new SqlStringLocalizer(GetAllFromDatabaseForResource(resourceSource.Name), resourceSource.Name);
            return _resourceLocalizations.GetOrAdd(resourceSource.Name, sqlStringLocalizer);
        }
 
        public IStringLocalizer Create(string baseName, string location)
        {
            if (_resourceLocalizations.Keys.Contains(baseName + location))
            {
                return _resourceLocalizations[baseName + location];
            }
 
            var sqlStringLocalizer = new SqlStringLocalizer(GetAllFromDatabaseForResource(baseName + location), baseName + location);
            return _resourceLocalizations.GetOrAdd(baseName + location, sqlStringLocalizer);
        }
 
        private Dictionary<string, string> GetAllFromDatabaseForResource(string resourceKey)
        {
            return _context.LocalizationRecords.Where(data => data.ResourceKey == resourceKey).ToDictionary(kvp => (kvp.Key + "." + kvp.LocalizationCulture), kvp => kvp.Text);
        }
    }
}

SqlStringLocalizer实现IStringLocalizer。 因为它只是GET资源，所以用作应用程序的单例。

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namespace Localization.SqlLocalizer.DbStringLocalizer
{
    using System;
    using System.Collections.Generic;
    using System.Globalization;
    using Microsoft.Extensions.Localization;
 
    public class SqlStringLocalizer : IStringLocalizer
    {
        private readonly Dictionary<string, string> _localizations;
 
        private readonly string _resourceKey;
        public SqlStringLocalizer(Dictionary<string, string> localizations, string resourceKey)
        {
            _localizations = localizations;
            _resourceKey = resourceKey;
        }
        public LocalizedString this[string name]
        {
            get
            {
                return new LocalizedString(name, GetText(name));
            }
        }
 
        public LocalizedString this[string name, params object[] arguments]
        {
            get
            {
                return new LocalizedString(name, GetText(name));
            }
        }
 
        public IEnumerable<LocalizedString> GetAllStrings(bool includeParentCultures)
        {
            throw new NotImplementedException();
        }
 
        public IStringLocalizer WithCulture(CultureInfo culture)
        {
            throw new NotImplementedException();
        }
 
        private string GetText(string key)
        {
 
#if NET451
            var culture = System.Threading.Thread.CurrentThread.CurrentCulture.ToString();
#elif NET46
            var culture = System.Threading.Thread.CurrentThread.CurrentCulture.ToString();
#else
            var culture = CultureInfo.CurrentCulture.ToString();
#endif
            string computedKey = $"{key}.{culture}";
 
            string result;
            if (_localizations.TryGetValue(computedKey, out result))
            {
                return result;
            }
            else
            {
                return _resourceKey + "." + computedKey;
            }
        }
    }
}

LocalizationModelContext类是实体框架核心DbContext实现。 这使用LocalizationRecord模型类进行数据访问。 影子属性用于数据库UpdatedTimestamp，在使用本地化数据库导入进行更新时将使用该属性。

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namespace Localization.SqlLocalizer.DbStringLocalizer
{
    using System;
    using System.Linq;
 
    using Microsoft.EntityFrameworkCore;
 
    // >dotnet ef migrations add LocalizationMigration
    public class LocalizationModelContext : DbContext
    {
        public LocalizationModelContext(DbContextOptions<LocalizationModelContext> options) :base(options)
        { }
 
        public DbSet<LocalizationRecord> LocalizationRecords { get; set; }
 
        protected override void OnModelCreating(ModelBuilder builder)
        {
            builder.Entity<LocalizationRecord>().HasKey(m => m.Id);
            //builder.Entity<LocalizationRecord>().HasKey(m => m.LocalizationCulture + m.Key);
 
            // shadow properties
            builder.Entity<LocalizationRecord>().Property<DateTime>("UpdatedTimestamp");
 
            base.OnModelCreating(builder);
        }
 
        public override int SaveChanges()
        {
            ChangeTracker.DetectChanges();
            updateUpdatedProperty<LocalizationRecord>();
            return base.SaveChanges();
        }
 
        private void updateUpdatedProperty<T>() where T : class
        {
            var modifiedSourceInfo =
                ChangeTracker.Entries<T>()
                    .Where(e => e.State == EntityState.Added || e.State == EntityState.Modified);
 
            foreach (var entry in modifiedSourceInfo)
            {
                entry.Property("UpdatedTimestamp").CurrentValue = DateTime.UtcNow;
            }
        }
    }
}

下一步

该应用程序可以打包为NuGet并添加到NuGet服务器。 该数据库可以优化。 我还可以添加一些额外的配置选项。 我想为SPA json文件以及可以由外部公司翻译的csv文件实现导入，导出功能。

我很乐意提供反馈，非常感谢您提供改进方法的提示。 也许可以将其添加到ASP.NET Core中。