content: /*
   *
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.bookkeeper.http.servlet;
  
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  import java.io.IOException;
  import java.io.Writer;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import org.apache.bookkeeper.http.AbstractHttpHandlerFactory;
  import org.apache.bookkeeper.http.HttpRouter;
  import org.apache.bookkeeper.http.HttpServer;
  import org.apache.bookkeeper.http.HttpServer.ApiType;
  import org.apache.bookkeeper.http.HttpServiceProvider;
  import org.apache.bookkeeper.http.service.HttpEndpointService;
  import org.apache.bookkeeper.http.service.HttpServiceRequest;
  import org.apache.bookkeeper.http.service.HttpServiceResponse;
  import org.apache.commons.io.IOUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Bookie http service servlet.
   *
   **/
  public class BookieHttpServiceServlet extends HttpServlet {
    static final Logger LOG = LoggerFactory.getLogger(BookieHttpServiceServlet.class);
  
    // url to api
    private final Map<String/*url*/, ApiType/*api*/> mappings = new ConcurrentHashMap<>();
  
    public BookieHttpServiceServlet(){
      HttpRouter<ApiType> router = new HttpRouter<HttpServer.ApiType>(
        new AbstractHttpHandlerFactory<ApiType>(BookieServletHttpServer.getBookieHttpServiceProvider()) {
          @Override
          public HttpServer.ApiType newHandler(HttpServer.ApiType apiType) {
            return apiType;
          }
        }) {
        @Override
        public void bindHandler(String endpoint, HttpServer.ApiType mapping) {
          mappings.put(endpoint, mapping);
        }
      };
      router.bindAll();
    }
  
    @Override
    @SuppressFBWarnings("RCN_REDUNDANT_NULLCHECK_WOULD_HAVE_BEEN_A_NPE")
    protected void service(HttpServletRequest httpRequest, HttpServletResponse httpResponse) throws IOException {
      HttpServiceRequest request = new HttpServiceRequest()
                                  .setMethod(httpServerMethod(httpRequest))
                                  .setParams(httpServletParams(httpRequest))
                                  .setBody(IOUtils.toString(httpRequest.getInputStream(), "UTF-8"));
      String uri = httpRequest.getRequestURI();
      HttpServiceResponse response;
      try {
        HttpServer.ApiType apiType = mappings.get(uri);
        HttpServiceProvider bookie = BookieServletHttpServer.getBookieHttpServiceProvider();
        if (bookie == null) {
          httpResponse.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
          return;
        }
        HttpEndpointService httpEndpointService = bookie.provideHttpEndpointService(apiType);
        if (httpEndpointService == null) {
          httpResponse.sendError(HttpServletResponse.SC_NOT_FOUND);
          return;
        }
        response = httpEndpointService.handle(request);
        httpResponse.setStatus(response.getStatusCode());
        try (Writer out = httpResponse.getWriter()) {
          out.write(response.getBody());
        }
      } catch (Throwable e) {
        LOG.error("Error while service Bookie API request {}", uri, e);
        httpResponse.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
      }
    }
  
  
    /**
     * Convert http request parameters to a map.
     */
    @SuppressWarnings("unchecked")
    Map<String, String> httpServletParams(HttpServletRequest request) {
      Map<String, String> map = new HashMap<>();
      for (Enumeration<String> param = request.getParameterNames();
           param.hasMoreElements();) {
        String pName = param.nextElement();
        map.put(pName, request.getParameter(pName));
      }
      return map;
    }
  
    /**
     * Get servlet request method and convert to the method that can be recognized by HttpServer.
     */
    HttpServer.Method httpServerMethod(HttpServletRequest request) {
      switch (request.getMethod()) {
        case "POST":
          return HttpServer.Method.POST;
        case "DELETE":
          return HttpServer.Method.DELETE;
        case "PUT":
          return HttpServer.Method.PUT;
        case "GET":
          return HttpServer.Method.GET;
        default:
          throw new UnsupportedOperationException("Unsupported http method");
      }
    }
  }
  