AspNetCore.RequestLocalizationPipeline

A helper project to add route localization in .NET Core Web API projects.

You can use it by adding it as a separate project and reference it in the Web.API project you have, or as a nuget package:

Install-Package AspNetCore.RequestLocalizationPipeline

What is it for ?

This package will help you pass culture through URL like this:

https://mydomain/en/api/myControler
// OR like this:
https://mydomain/en-US/api/myController

The parts before the myController will be considered as [route convention|https://docs.microsoft.com/en-us/aspnet/core/fundamentals/routing?view=aspnetcore-3.0], you can set the culture route key where ever you want in the convention area, so it'll be applied to all your controllers.

notes: the default provider that comes with AspNetCore doesn't do the work.

How to use it:

There're couple of snippets you need to add to your startup.cs before you'll be able to use this package.

1. Specify the route key you want to use for culture:

const string langKey = "lang";

2. Define a route convention as a readonly field in startup:

readonly string ROUTE_CONVENTION = "{" + langKey + "}/api";

Adding a route convention to your controllers, where a convention is a prefix that will be prepended to all the routes in your project.

3. In method ConfigureServices we have to prepare the localization options and add it as a singleton to be used later:

public void ConfigureServices(IServiceCollection services)
{
	// An extension method from Microsoft.Extensions.DependencyInjection to add required services for localization.
	services.AddLocalization(options => options.ResourcesPath = "Resources");

	// An extension method from the package to prepare the options and add the object as Singleton in DI.
	// First parameter is the same route key you defined in step 1.
	// Second parameter is the default culture you want your api to use in case no culture passed through URL.
	services.AddLocalizationOptions(langKey);
}

Notes:

• AddLocalizationOptions will add the RouteDataRequestCultureProvider in index 0 of the list RequestCultureProviders.
• By default the package adds support for two languages (en, ar), if you need to add more you do this by filling this list before calling the method AddLocalizationOptions like this:

   LocalizationOptions.SupportedCultures.Add(new CultureInfo("fr-FR"));
   // and you can add more languages
   services.AddLocalizationOptions(langKey);
  

4. Now we will add the localization pipeline as a global action filter in your project:

services.AddMvc(opts =>
    {
		...
		// Make sure it's set before any other filters ,if you have, if you want to use the culture in them.
        opts.AddLocalizationPipeLine(ROUTE_CONVENTION);
		...
    })

5. In Configure method, we'll add a rewriter to make sure we accept requests that don't have any culutre in the position of the specified culture key:

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
	app.UseDefaultCultureRewrite(ROUTE_CONVENTION);
}

6. In Configure method, we'll add a rewriter to make sure we accept cultures in two letters (not only ISO 3 letters):

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
	app.UseDefaultCultureRewrite(ROUTE_CONVENTION)
		.UseTwoLettersCultureRewrite(ROUTE_CONVENTION);
}

Note:

If you want to make sure if it's working, comment app.UseMvc() in method Configure and add this temporarly:

app.Run(context => context.Response.WriteAsync(
            $"Rewritten or Redirected Url: " +
            $"{context.Request.Path + context.Request.QueryString}"));

At the end, this is my first project on github, I may did something wrong in it, or it's not clean code, please advice and feel free to contribute.