Asp.net Core localization with json files

Question

I'm trying to find a good tutorial about asp.net localization. In the official documentation, the explanation are about .resx files and I want to use json files.

If someone have a good tutorial on how to write the middleware to do that.

Thanks

Answer 1

Nuget Package

https://www.nuget.org/packages/Askmethat.Aspnet.JsonLocalizer/

Solution

After some investigations, I finally find an example in Asp/Localization GitHub.

I provide here for people that want to use a flat JSON without breaking default culture provider.

Data :

The flat JSON:

[
  {
    "Key": "Hello",
    "LocalizedValue" : {
      "fr-FR": "Bonjour",
      "en-US": "Hello"
    }
  }
]

The C# model:

class JsonLocalization
{
    public string Key { get; set; }
    public Dictionary<string, string> LocalizedValue = new Dictionary<string, string>();
}

The Middleware

The Factory

This is just to have access to the CultureInfo is the StringLocalizer.

 public class JsonStringLocalizerFactory : IStringLocalizerFactory
 {
    public IStringLocalizer Create(Type resourceSource)
    {
        return new JsonStringLocalizer();
    }

    public IStringLocalizer Create(string baseName, string location)
    {
        return new JsonStringLocalizer();
    }
 }

The Localizer

The logic to get the data from the JSON file

public class JsonStringLocalizer : IStringLocalizer
{
    List<JsonLocalization> localization = new List<JsonLocalization>();

    public JsonStringLocalizer()
    {
        //read all json file
        JsonSerializer serializer = new JsonSerializer();
        localization = JsonConvert.DeserializeObject<List<JsonLocalization>>(File.ReadAllText(@"localization.json"));
    }

    public LocalizedString this[string name]
    {
        get
        {
            var value = GetString(name);
            return new LocalizedString(name, value ?? name, resourceNotFound: value == null);
        }
    }

    public LocalizedString this[string name, params object[] arguments]
    {
        get
        {
            var format = GetString(name);
            var value = string.Format(format ?? name, arguments);
            return new LocalizedString(name, value, resourceNotFound: format == null);
        }
    }

    public IEnumerable<LocalizedString> GetAllStrings(bool includeParentCultures)
    {
        return localization.Where(l => l.LocalizedValue.Keys.Any(lv => lv == CultureInfo.CurrentCulture.Name)).Select(l => new LocalizedString(l.Key, l.LocalizedValue[CultureInfo.CurrentCulture.Name], true));
    }

    public IStringLocalizer WithCulture(CultureInfo culture)
    {
        return new JsonStringLocalizer();
    }

    private string GetString(string name)
    {
        var query = localization.Where(l => l.LocalizedValue.Keys.Any(lv => lv == CultureInfo.CurrentCulture.Name));
        var value = query.FirstOrDefault(l => l.Key == name);
        return value.LocalizedValue[CultureInfo.CurrentCulture.Name];
    }
}

With this solution you are able to use the basic IStringLocalizer in your Views and Controllers.

Of course if you have a big json file, you can use IMemoryCache or IDistributedMemoryCache to improve performance.

EDIT :

In the application Startup add this lines to use your own implementation :

services.AddSingleton<IStringLocalizerFactory, JsonStringLocalizerFactory>();
services.AddSingleton<IStringLocalizer, JsonStringLocalizer>();
services.AddLocalization(options => options.ResourcesPath = "Resources");

After that you can configure as you want your globalization preferences.