content: package act.util;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2019 ActFramework
   * %%
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   * #L%
   */
  
  import act.Act;
  import act.app.event.SysEventId;
  import act.inject.util.LoadResource;
  import act.job.Cron;
  import act.job.OnAppStart;
  import okhttp3.OkHttpClient;
  import okhttp3.Request;
  import okhttp3.Response;
  import org.osgl.util.IO;
  
  import javax.annotation.PostConstruct;
  import javax.inject.Singleton;
  import java.net.UnknownHostException;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  /**
   * Download top level domain list from http://data.iana.org/TLD/tlds-alpha-by-domain.txt.
   *
   * If it cannot be download then use the built in one in resource/tld.list
   */
  @Singleton
  public class TopLevelDomainList extends LogSupport {
  
      public static final String CRON_TLD_RELOAD = "cron.act.tld-reload";
  
      @LoadResource("tld.list")
      private List<String> list;
      private Set<String> quickLookup;
  
      public TopLevelDomainList() {
      }
  
      /**
       * Check if a string is top level domain
       * @param s the string to be checked
       * @return `true` if `s` is top level domain or `false` otherwise
       */
      public boolean isTld(String s) {
          return quickLookup.contains(s.toUpperCase());
      }
  
      /**
       * Strip the first comment line from the tld.list and build quick lookup
       */
      @PostConstruct
      public void filter() {
          doFilter();
      }
  
      private void doFilter() {
          if (list.get(0).startsWith("#")) {
              list.remove(0);
          }
          quickLookup = new HashSet<>(list);
      }
  
      /**
       * Reload list from http://data.iana.org/TLD/tlds-alpha-by-domain.txt
       *
       * This method is scheduled to be executed at the time setup in `cron.act.tld-reload`
       * the default value is 0 2 * * * *, i.e. 2am every day.
       */
      @Cron(CRON_TLD_RELOAD)
      public void refresh() {
          if (!Act.app().isStarted()) {
              // in very rare case that cron job running while app is hot-reloading
              Act.app().jobManager().on(SysEventId.POST_STARTED, new Runnable() {
                  @Override
                  public void run() {
                      refresh();
                  }
              });
              return;
          }
          try {
              downloadTld();
          } catch (UnknownHostException e) {
              // ignore - refer to https://github.com/actframework/actframework/issues/1265
          } catch (Exception e) {
              warn(e, "error download TLD list file");
          }
      }
  
      private void downloadTld() throws Exception {
          OkHttpClient http = new OkHttpClient.Builder().build();
          Request req = new Request.Builder().url("http://data.iana.org/TLD/tlds-alpha-by-domain.txt").get().build();
          Response resp = http.newCall(req).execute();
          List<String> newList = IO.read(resp.body().charStream()).toLines();
          resp.close();
          list = newList;
          filter();
      }
  
      public static void main(String[] args) throws Exception {
          TopLevelDomainList list = new TopLevelDomainList();
          list.downloadTld();
          System.out.println(list.list);
      }
  
  }
  