通过 URL 路径设置请求文化

默认情况下，内置的 Request Localization 中间件仅支持通过 query，cookie 或 Accept-Language 标头设置区域性。这个例子展示了如何创建一个中间件，它允许将文化设置为路径的一部分，就像在/api/en-US/products 中一样。

此示例中间件假定区域设置位于路径的第二个段中。

public class UrlRequestCultureProvider : RequestCultureProvider
{
    private static readonly Regex LocalePattern = new Regex(@"^[a-z]{2}(-[a-z]{2,4})?$",
                                                        RegexOptions.IgnoreCase);

    public override Task<ProviderCultureResult> DetermineProviderCultureResult(HttpContext httpContext)
    {
        if (httpContext == null)
        {
            throw new ArgumentNullException(nameof(httpContext));
        }

        var url = httpContext.Request.Path;

        // Right now it's not possible to use httpContext.GetRouteData()
        // since it uses IRoutingFeature placed in httpContext.Features when
        // Routing Middleware registers. It's not set when the Localization Middleware
        // is called, so this example simply assumes the locale will always 
        // be located in the second segment of a path, like in /api/en-US/products
        var parts = httpContext.Request.Path.Value.Split('/');
        if (parts.Length < 3)
        {
            return Task.FromResult<ProviderCultureResult>(null);
        }

        if (!LocalePattern.IsMatch(parts[2]))
        {
            return Task.FromResult<ProviderCultureResult>(null);
        }

        var culture = parts[2];
        return Task.FromResult(new ProviderCultureResult(culture));
    }
}

中间件注册

var localizationOptions = new RequestLocalizationOptions
{
    SupportedCultures = new List<CultureInfo>
    {
        new CultureInfo("de-DE"),
        new CultureInfo("en-US"),
        new CultureInfo("en-GB")
    },
    SupportedUICultures = new List<CultureInfo>
    {
        new CultureInfo("de-DE"),
        new CultureInfo("en-US"),
        new CultureInfo("en-GB")
    },
    DefaultRequestCulture = new RequestCulture("en-US")
};

// Adding our UrlRequestCultureProvider as first object in the list
localizationOptions.RequestCultureProviders.Insert(0, new UrlRequestCultureProvider
{
    Options = localizationOptions
});

app.UseRequestLocalization(localizationOptions);

自定义路线约束

路径约束示例中显示了添加和创建自定义路径约束。使用约束简化了自定义路径约束的使用。

注册路线

不使用自定义约束注册路由的示例

app.UseMvc(routes => 
{ 
    routes.MapRoute( 
        name: "default", 
        template: "api/{culture::regex(^[a-z]{{2}}-[A-Za-z]{{4}}$)}}/{controller}/{id?}"); 
    routes.MapRoute( 
        name: "default", 
        template: "api/{controller}/{id?}"); 
});