content: package act.controller.builtin;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2017 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.ActionContext;
  import act.app.App;
  import act.app.event.SysEventId;
  import org.osgl.cache.CacheService;
  import org.osgl.http.H;
  import org.osgl.inject.annotation.Configuration;
  import org.osgl.mvc.result.Result;
  import org.osgl.mvc.result.TooManyRequests;
  import org.osgl.util.E;
  import org.osgl.util.S;
  
  import javax.inject.Singleton;
  
  @Singleton
  public class ThrottleFilter {
  
      public static final String CACHE_NAME = "act.throttle";
  
      private CacheService cache;
  
      @Configuration("act.req.throttle")
      private int throttle;
  
      @Configuration("req.throttle.expire.scale.enabled")
      private boolean expireScale;
  
      public ThrottleFilter() {
          final App app = Act.app();
          app.jobManager().on(SysEventId.CLASS_LOADER_INITIALIZED, "ThrottleFilter:initCache", new Runnable() {
              @Override
              public void run() {
                  cache = app.cache(CACHE_NAME);
              }
          }, true);
      }
  
      public ThrottleFilter(int throttle, boolean expireScale) {
          E.illegalArgumentIf(throttle < 1);
          this.throttle = throttle;
          this.expireScale = expireScale;
          final App app = Act.app();
          app.jobManager().on(SysEventId.CLASS_LOADER_INITIALIZED, "ThrottleFilter:initCache", new Runnable() {
              @Override
              public void run() {
                  cache = app.cache(CACHE_NAME);
              }
          }, true);
      }
  
      public Result handle(ActionContext actionContext) {
          String key = cacheKey(actionContext);
          if (!expireScale) {
              if (throttle <= cache.incr(key, 1)) {
                  return TooManyRequests.get();
              }
          } else {
              Integer curReqCnt = cache.get(key);
              if (null == curReqCnt) {
                  curReqCnt = 0;
              }
              int timeout = curReqCnt + 1;
              cache.incr(key, timeout);
              if (curReqCnt >= throttle) {
                  return TooManyRequests.get();
              }
          }
          return null;
      }
  
      private String cacheKey(ActionContext context) {
          H.Request req = context.req();
          return S.concat(req.method(), req.url(), req.ip());
      }
  }
  