content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * 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.
   */
  
  package com.alibaba.nacos.client.config.impl;
  
  import com.alibaba.nacos.api.common.Constants;
  import com.alibaba.nacos.api.exception.NacosException;
  import com.alibaba.nacos.client.utils.LogUtils;
  import com.alibaba.nacos.client.utils.ParamUtil;
  import com.alibaba.nacos.common.http.AbstractHttpClientFactory;
  import com.alibaba.nacos.common.http.HttpClientBeanHolder;
  import com.alibaba.nacos.common.http.HttpClientConfig;
  import com.alibaba.nacos.common.http.HttpClientFactory;
  import com.alibaba.nacos.common.http.client.HttpClientRequestInterceptor;
  import com.alibaba.nacos.common.http.client.NacosRestTemplate;
  import com.alibaba.nacos.common.http.client.response.HttpClientResponse;
  import com.alibaba.nacos.common.http.param.Header;
  import com.alibaba.nacos.common.lifecycle.Closeable;
  import com.alibaba.nacos.common.model.RequestHttpEntity;
  import com.alibaba.nacos.common.utils.ExceptionUtil;
  import com.alibaba.nacos.common.utils.JacksonUtils;
  import com.alibaba.nacos.common.utils.MD5Utils;
  import org.slf4j.Logger;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.URI;
  import java.util.List;
  
  import static com.alibaba.nacos.client.utils.LogUtils.NAMING_LOGGER;
  
  /**
   * config http Manager.
   *
   * @author mai.jh
   */
  public class ConfigHttpClientManager implements Closeable {
      
      private static final Logger LOGGER = LogUtils.logger(ConfigHttpClientManager.class);
      
      private static final HttpClientFactory HTTP_CLIENT_FACTORY = new ConfigHttpClientFactory();
      
      private static final int CON_TIME_OUT_MILLIS = ParamUtil.getConnectTimeout();
      
      private static final int READ_TIME_OUT_MILLIS = ParamUtil.getReadTimeout();
      
      private final LimiterHttpClientRequestInterceptor limiterHttpClientRequestInterceptor = new LimiterHttpClientRequestInterceptor();
      
      private static class ConfigHttpClientManagerInstance {
          
          private static final ConfigHttpClientManager INSTANCE = new ConfigHttpClientManager();
      }
      
      public static ConfigHttpClientManager getInstance() {
          return ConfigHttpClientManagerInstance.INSTANCE;
      }
      
      @Override
      public void shutdown() throws NacosException {
          NAMING_LOGGER.info("[ConfigHttpClientManager] Start destroying NacosRestTemplate");
          try {
              HttpClientBeanHolder.shutdownNacosSyncRest(HTTP_CLIENT_FACTORY.getClass().getName());
          } catch (Exception ex) {
              NAMING_LOGGER.error("[ConfigHttpClientManager] An exception occurred when the HTTP client was closed : {}",
                      ExceptionUtil.getStackTrace(ex));
          }
          NAMING_LOGGER.info("[ConfigHttpClientManager] Completed destruction of NacosRestTemplate");
      }
      
      /**
       * get connectTimeout.
       *
       * @param connectTimeout connectTimeout
       * @return int return max timeout
       */
      public int getConnectTimeoutOrDefault(int connectTimeout) {
          return Math.max(CON_TIME_OUT_MILLIS, connectTimeout);
      }
      
      /**
       * get NacosRestTemplate Instance.
       *
       * @return NacosRestTemplate
       */
      public NacosRestTemplate getNacosRestTemplate() {
          NacosRestTemplate nacosRestTemplate = HttpClientBeanHolder.getNacosRestTemplate(HTTP_CLIENT_FACTORY);
          List<HttpClientRequestInterceptor> interceptors = nacosRestTemplate.getInterceptors();
          if (!interceptors.contains(limiterHttpClientRequestInterceptor)) {
              interceptors.add(limiterHttpClientRequestInterceptor);
          }
          return nacosRestTemplate;
      }
      
      /**
       * ConfigHttpClientFactory.
       */
      private static class ConfigHttpClientFactory extends AbstractHttpClientFactory {
          
          @Override
          protected HttpClientConfig buildHttpClientConfig() {
              return HttpClientConfig.builder().setConTimeOutMillis(CON_TIME_OUT_MILLIS)
                      .setReadTimeOutMillis(READ_TIME_OUT_MILLIS).build();
          }
          
          @Override
          protected Logger assignLogger() {
              return LOGGER;
          }
      }
      
      /**
       * config Limiter implement.
       */
      private static class LimiterHttpClientRequestInterceptor implements HttpClientRequestInterceptor {
          
          @Override
          public boolean isIntercept(URI uri, String httpMethod, RequestHttpEntity requestHttpEntity) {
              final String body = requestHttpEntity.isEmptyBody() ? "" : JacksonUtils.toJson(requestHttpEntity.getBody());
              return Limiter.isLimit(MD5Utils.md5Hex(uri + body, Constants.ENCODE));
          }
          
          @Override
          public HttpClientResponse intercept() {
              return new LimitResponse();
          }
      }
      
      /**
       * Limit Interrupt response.
       */
      private static class LimitResponse implements HttpClientResponse {
          
          @Override
          public Header getHeaders() {
              return Header.EMPTY;
          }
          
          @Override
          public InputStream getBody() throws IOException {
              return new ByteArrayInputStream("More than client-side current limit threshold".getBytes());
          }
          
          @Override
          public int getStatusCode() {
              return NacosException.CLIENT_OVER_THRESHOLD;
          }
          
          @Override
          public String getStatusText() {
              return null;
          }
          
          @Override
          public void close() {
          
          }
      }
  }
  