content: /*
   * Copyright 2014 Allan Ditzel
   *
   * 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.allanditzel.springframework.security.web.csrf;
  
  import org.springframework.security.web.csrf.CsrfToken;
  import org.springframework.web.filter.OncePerRequestFilter;
  
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.io.IOException;
  
  /**
   * Binds a {@link org.springframework.security.web.csrf.CsrfToken} to the {@link HttpServletResponse}
   * headers if the Spring {@link org.springframework.security.web.csrf.CsrfFilter} has placed one in the {@link HttpServletRequest}.
   *
   * Based on the work found in: <a href="http://stackoverflow.com/questions/20862299/with-spring-security-3-2-0-release-how-can-i-get-the-csrf-token-in-a-page-that">Stack Overflow</a>
   *
   * @author Allan Ditzel
   * @since 1.0
   */
  public class CsrfTokenResponseHeaderBindingFilter extends OncePerRequestFilter {
      protected static final String REQUEST_ATTRIBUTE_NAME = "_csrf";
      protected static final String RESPONSE_HEADER_NAME = "X-CSRF-HEADER";
      protected static final String RESPONSE_PARAM_NAME = "X-CSRF-PARAM";
      protected static final String RESPONSE_TOKEN_NAME = "X-CSRF-TOKEN";
  
      @Override
      protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, javax.servlet.FilterChain filterChain) throws ServletException, IOException {
          CsrfToken token = (CsrfToken) request.getAttribute(REQUEST_ATTRIBUTE_NAME);
  
          if (token != null) {
              response.setHeader(RESPONSE_HEADER_NAME, token.getHeaderName());
              response.setHeader(RESPONSE_PARAM_NAME, token.getParameterName());
              response.setHeader(RESPONSE_TOKEN_NAME , token.getToken());
          }
  
          filterChain.doFilter(request, response);
      }
  }
  