AcceptLanguageLocaleResolver.java

package com.github.aesteve.vertx.nubes.i18n.impl;

import com.github.aesteve.vertx.nubes.i18n.LocaleResolver;
import io.vertx.ext.web.RoutingContext;

import java.util.List;
import java.util.Locale;
import java.util.Locale.LanguageRange;

import static io.vertx.core.http.HttpHeaders.ACCEPT_LANGUAGE;

public class AcceptLanguageLocaleResolver implements LocaleResolver {

  @Override
  public Locale resolve(RoutingContext context, List<Locale> availableLocales) {
    String accept = context.request().getHeader(ACCEPT_LANGUAGE.toString());
    if (accept == null) {
      return null;
    }
    List<LanguageRange> ranges = LanguageRange.parse(accept);
    if (ranges.isEmpty()) {
      return null;
    }
    return Locale.lookup(ranges, availableLocales);
  }

}