/*
 * Copyright 2002-2021 the original author or authors.
 *
 * 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
 *
 *      https://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.springframework.web.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

import org.springframework.http.server.RequestPath;
import org.springframework.web.util.ServletRequestPathUtils;

A Filter to parse and cache a RequestPath for further access throughout the filter chain. This is useful when parsed PathPatterns are in use anywhere in an application instead of String pattern matching with PathMatcher. 
Note that in Spring MVC, the DispatcherServlet will also parse and cache the RequestPath if it detects that parsed PathPatterns are enabled for any HandlerMapping but it will skip doing that if it finds the ServletRequestPathUtils.PATH_ATTRIBUTE already exists. 
Author:
Rossen Stoyanchev
Since:
5.3/**
 * A {@code Filter} to {@link ServletRequestPathUtils#parseAndCache parse}
 * and cache a {@link org.springframework.http.server.RequestPath} for further
 * {@link ServletRequestPathUtils#getParsedRequestPath access} throughout the
 * filter chain. This is useful when parsed
 * {@link org.springframework.web.util.pattern.PathPattern}s are in use anywhere
 * in an application instead of String pattern matching with
 * {@link org.springframework.util.PathMatcher}.
 * <p>Note that in Spring MVC, the {@code DispatcherServlet} will also parse and
 * cache the {@code RequestPath} if it detects that parsed {@code PathPatterns}
 * are enabled for any {@code HandlerMapping} but it will skip doing that if it
 * finds the {@link ServletRequestPathUtils#PATH_ATTRIBUTE} already exists.
 *
 * @author Rossen Stoyanchev
 * @since 5.3
 */
public class ServletRequestPathFilter implements Filter {

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {

		RequestPath previousRequestPath = (RequestPath) request.getAttribute(ServletRequestPathUtils.PATH_ATTRIBUTE);
		ServletRequestPathUtils.parseAndCache((HttpServletRequest) request);
		try {
			chain.doFilter(request, response);
		}
		finally {
			ServletRequestPathUtils.setParsedRequestPath(previousRequestPath, request);
		}
	}

}