Localize request via according to provided route value
By default, ASP.NET has three request culture providers:
- QueryStringRequestCultureProvider
- CookieRequestCultureProivder
- AcceptLanguageHeaderRequestCultureProvider
But there is no RouteValueRequestCultureProvider, so lets create one.
Inside “Utilities” folder, create a new class name it “RouteValueRequestCultureProvider.cs”, and implement IRequestCulture provider interface
/// RouteValueRequestCultureProvider.cs ///
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Localization;
using System.Globalization;
using System.Linq;
using System.Threading.Tasks;
namespace MyTrips.Utilities
{
public class RouteValueRequestCultureProvider : IRequestCultureProvider
{
private readonly CultureInfo[] _cultures;
public RouteValueRequestCultureProvider(CultureInfo[] cultures)
{
_cultures = cultures;
}
/// <summary>
/// get {culture} route value from path string,
/// </summary>
/// <param name="httpContext"></param>
/// <returns>ProviderCultureResult depends on path {culture} route parameter, or default culture</returns>
public Task<ProviderCultureResult> DetermineProviderCultureResult(HttpContext httpContext)
{
var defaultCulture = "en";
var path = httpContext.Request.Path;
if (string.IsNullOrWhiteSpace(path))
{
return Task.FromResult(new ProviderCultureResult(defaultCulture));
}
var routeValues = httpContext.Request.Path.Value.Split('/');
if (routeValues.Count() <= 1)
{
return Task.FromResult(new ProviderCultureResult(defaultCulture));
}
if (!_cultures.Any(x => x.Name.ToLower() == routeValues[1].ToLower()))
{
return Task.FromResult(new ProviderCultureResult(defaultCulture));
}
return Task.FromResult(new ProviderCultureResult(routeValues[1]));
}
}
}
We extracted the first path parameter because we managed our {culture?} route value to be the first parameter in the request path. The return result is ProviderCultureResult, it depends on the route value. If no route value provided default culture “en” will be returned.
Now we need to configure localization options in startup file, so we use our RouteValueRequestCulture provider as the default request localization provider. Under “Utilities” folder create a new class name it “LocalizationExtension.cs” and create an extension method for IServiceCollection:
/// LocalizationExtension.cs ///
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Localization;
using Microsoft.Extensions.DependencyInjection;
using System.Globalization;
using System.Linq;
namespace MyTrips.Utilities
{
public static class LocalizationExtension
{
/// <summary>
/// localize request according to {culture} route value.
/// define supported cultures list,
/// define default culture for fallback,
/// customize culture info e.g.: dat time format, digit shape,...
/// </summary>
/// <param name="services"></param>
public static void ConfigureRequestLocalization(this IServiceCollection services)
{
var cultures = new CultureInfo[]
{
new CultureInfo("en"),
new CultureInfo("tr"),
new CultureInfo("es"),
new CultureInfo("fa"),
new CultureInfo("hi"),
new CultureInfo("ar-SY"),
new CultureInfo("ar") {
/* change calendar to Grgorian */
DateTimeFormat = { Calendar = new GregorianCalendar() },
/* change digit shape */
NumberFormat = { NativeDigits = "0 1 2 3 4 5 6 7 8 9".Split(" ") }
}
};
services.Configure<RequestLocalizationOptions>(ops =>
{
ops.DefaultRequestCulture = new RequestCulture("en");
ops.SupportedCultures = cultures.OrderBy(x=>x.EnglishName).ToList();
ops.SupportedUICultures = cultures.OrderBy(x => x.EnglishName).ToList();
// add RouteValueRequestCultureProvider to the beginning of the providers list.
ops.RequestCultureProviders.Insert(0,
new RouteValueRequestCultureProvider(cultures));
});
}
}
}
We have defined a list of supported cultures (en, tr, es, hi, fa and ar) and defined a default culture "en", you may define your own cultures list as you wish. Then we have inserted our RouteValueRequestCultureProvider at the beginning of the request culture providers list, so in case no route value for culture, the next provider will try to find culture value in query string, cookie or accepted header value.
In “startup.cs” file call the extension method we have created then configure the app to use request localization middlware:
/// startup.cs ///
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using MyTrips.Utilities;
namespace MyTrips
{
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
services.Configure<CookiePolicyOptions>(options =>
{
// This lambda determines whether user consent for non-essential cookies is needed for a given request.
options.CheckConsentNeeded = context => true;
options.MinimumSameSitePolicy = SameSiteMode.None;
});
services.ConfigureRequestLocalization();
services.AddMvc()
.SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
.AddRazorPagesOptions(o => {
o.Conventions.Add(new CultureTemplateRouteModelConvention());
});
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseExceptionHandler("/Error");
app.UseHsts();
}
app.UseRequestLocalization();
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseCookiePolicy();
app.UseMvc();
}
}
}
Next : Creating Language Dropdown Navigation
Demo Project: My trips application
Source code on github: MyTrips