About load supported cultures from DB in .NET CORE - database

Question

I have a Language entity with all supported languages in my db, each language has a culture string attribute. I want to load supported cultures from DB.
In my service initializer I have it:
public void ConfigureServices(IServiceCollection services)
{
// ... previous configuration not shown
services.Configure<RequestLocalizationOptions>(
opts =>
{
var supportedCultures = new List<CultureInfo>
{
new CultureInfo("en-GB"),
new CultureInfo("en-US"),
new CultureInfo("en"),
new CultureInfo("fr-FR"),
new CultureInfo("fr"),
};
opts.DefaultRequestCulture = new RequestCulture("en-GB");
// Formatting numbers, dates, etc.
opts.SupportedCultures = supportedCultures;
// UI strings that we have localized.
opts.SupportedUICultures = supportedCultures;
});
}
How I can access my DB context inside it?
There is any other better way to do it?

Answer 1

I don't think there's an out of the box solution for this.
However, you can implement your own middleware that achieves this by using ASP.Net's RequestLocalizationMiddleware:
public class CustomRequestLocalizationMiddleware
{
private readonly RequestDelegate next;
private readonly ILoggerFactory loggerFactory;
public CustomRequestLocalizationMiddleware(RequestDelegate next, ILoggerFactory loggerFactory)
{
this.next = next;
this.loggerFactory = loggerFactory;
}
public async Task Invoke(HttpContext context /* You can inject services here, such as DbContext or IDbConnection*/)
{
// You can search your database for your supported and/or default languages here
// This query will execute for all requests, so consider using caching
var cultures = await Task.FromResult(new[] { "en" });
var defaultCulture = await Task.FromResult("en");
// You can configure the options here as you would do by calling services.Configure<RequestLocalizationOptions>()
var options = new RequestLocalizationOptions()
.AddSupportedCultures(cultures)
.AddSupportedUICultures(cultures)
.SetDefaultCulture(defaultCulture);
// Finally, we instantiate ASP.Net's default RequestLocalizationMiddleware and call it
var defaultImplementation = new RequestLocalizationMiddleware(next, Options.Create(options), loggerFactory);
await defaultImplementation.Invoke(context);
}
}
Then, we inject the required services and use the custom middleware in Startup.cs or Program.cs as follows:
services.AddLocalization()
/* ... */
app.UseMiddleware<CustomRequestLocalizationMiddleware>()
Do not call app.UseRequestLocalization(), because this would call ASP.Net's RequestLocalizationMiddleware again with the default options, and override the culture that has been resolved previously.