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 backtype.storm.security.auth;
  
  import java.security.Principal;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  import javax.security.auth.Subject;
  import javax.servlet.http.HttpServletRequest;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import backtype.storm.security.auth.ReqContext;
  
  public class DefaultHttpCredentialsPlugin implements IHttpCredentialsPlugin {
      private static final Logger LOG = LoggerFactory.getLogger(DefaultHttpCredentialsPlugin.class);
  
      /**
       * No-op
       * 
       * @param storm_conf Storm configuration
       */
      @Override
      public void prepare(Map storm_conf) {
          // Do nothing.
      }
  
      /**
       * Gets the user name from the request principal.
       * 
       * @param req the servlet request
       * @return the authenticated user, or null if none is authenticated
       */
      @Override
      public String getUserName(HttpServletRequest req) {
          Principal princ = null;
          if (req != null && (princ = req.getUserPrincipal()) != null) {
              String userName = princ.getName();
              if (userName != null && !userName.isEmpty()) {
                  LOG.debug("HTTP request had user (" + userName + ")");
                  return userName;
              }
          }
          return null;
      }
  
      /**
       * Populates a given context with a new Subject derived from the credentials in a servlet request.
       * 
       * @param context the context to be populated
       * @param req the servlet request
       * @return the context
       */
      @Override
      public ReqContext populateContext(ReqContext context, HttpServletRequest req) {
          String userName = getUserName(req);
  
          String doAsUser = req.getHeader("doAsUser");
          if (doAsUser == null) {
              doAsUser = req.getParameter("doAsUser");
          }
  
          if (doAsUser != null) {
              context.setRealPrincipal(new SingleUserPrincipal(userName));
              userName = doAsUser;
          }
  
          Set<Principal> principals = new HashSet<Principal>();
          if (userName != null) {
              Principal p = new SingleUserPrincipal(userName);
              principals.add(p);
          }
          Subject s = new Subject(true, principals, new HashSet(), new HashSet());
          context.setSubject(s);
  
          return context;
      }
  }
  