001/*
002 * Copyright 2002-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.filter;
018
019import java.io.IOException;
020import java.io.InputStream;
021import java.nio.charset.Charset;
022import java.util.ArrayList;
023import java.util.Arrays;
024import java.util.Collections;
025import java.util.Enumeration;
026import java.util.LinkedHashMap;
027import java.util.LinkedHashSet;
028import java.util.List;
029import java.util.Map;
030import java.util.Set;
031
032import javax.servlet.FilterChain;
033import javax.servlet.ServletException;
034import javax.servlet.http.HttpServletRequest;
035import javax.servlet.http.HttpServletRequestWrapper;
036import javax.servlet.http.HttpServletResponse;
037
038import org.springframework.http.HttpInputMessage;
039import org.springframework.http.MediaType;
040import org.springframework.http.converter.FormHttpMessageConverter;
041import org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter;
042import org.springframework.http.server.ServletServerHttpRequest;
043import org.springframework.lang.Nullable;
044import org.springframework.util.Assert;
045import org.springframework.util.CollectionUtils;
046import org.springframework.util.MultiValueMap;
047import org.springframework.util.StringUtils;
048
049/**
050 * {@code Filter} that parses form data for HTTP PUT, PATCH, and DELETE requests
051 * and exposes it as Servlet request parameters. By default the Servlet spec
052 * only requires this for HTTP POST.
053 *
054 * @author Rossen Stoyanchev
055 * @since 5.1
056 */
057public class FormContentFilter extends OncePerRequestFilter {
058
059        private static final List<String> HTTP_METHODS = Arrays.asList("PUT", "PATCH", "DELETE");
060
061        private FormHttpMessageConverter formConverter = new AllEncompassingFormHttpMessageConverter();
062
063
064        /**
065         * Set the converter to use for parsing form content.
066         * <p>By default this is an instance of {@link AllEncompassingFormHttpMessageConverter}.
067         */
068        public void setFormConverter(FormHttpMessageConverter converter) {
069                Assert.notNull(converter, "FormHttpMessageConverter is required");
070                this.formConverter = converter;
071        }
072
073        /**
074         * The default character set to use for reading form data.
075         * This is a shortcut for:<br>
076         * {@code getFormConverter.setCharset(charset)}.
077         */
078        public void setCharset(Charset charset) {
079                this.formConverter.setCharset(charset);
080        }
081
082
083        @Override
084        protected void doFilterInternal(
085                        HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
086                        throws ServletException, IOException {
087
088                MultiValueMap<String, String> params = parseIfNecessary(request);
089                if (!CollectionUtils.isEmpty(params)) {
090                        filterChain.doFilter(new FormContentRequestWrapper(request, params), response);
091                }
092                else {
093                        filterChain.doFilter(request, response);
094                }
095        }
096
097        @Nullable
098        private MultiValueMap<String, String> parseIfNecessary(HttpServletRequest request) throws IOException {
099                if (!shouldParse(request)) {
100                        return null;
101                }
102
103                HttpInputMessage inputMessage = new ServletServerHttpRequest(request) {
104                        @Override
105                        public InputStream getBody() throws IOException {
106                                return request.getInputStream();
107                        }
108                };
109                return this.formConverter.read(null, inputMessage);
110        }
111
112        private boolean shouldParse(HttpServletRequest request) {
113                String contentType = request.getContentType();
114                String method = request.getMethod();
115                if (StringUtils.hasLength(contentType) && HTTP_METHODS.contains(method)) {
116                        try {
117                                MediaType mediaType = MediaType.parseMediaType(contentType);
118                                return MediaType.APPLICATION_FORM_URLENCODED.includes(mediaType);
119                        }
120                        catch (IllegalArgumentException ex) {
121                        }
122                }
123                return false;
124        }
125
126
127        private static class FormContentRequestWrapper extends HttpServletRequestWrapper {
128
129                private MultiValueMap<String, String> formParams;
130
131                public FormContentRequestWrapper(HttpServletRequest request, MultiValueMap<String, String> params) {
132                        super(request);
133                        this.formParams = params;
134                }
135
136                @Override
137                @Nullable
138                public String getParameter(String name) {
139                        String queryStringValue = super.getParameter(name);
140                        String formValue = this.formParams.getFirst(name);
141                        return (queryStringValue != null ? queryStringValue : formValue);
142                }
143
144                @Override
145                public Map<String, String[]> getParameterMap() {
146                        Map<String, String[]> result = new LinkedHashMap<>();
147                        Enumeration<String> names = getParameterNames();
148                        while (names.hasMoreElements()) {
149                                String name = names.nextElement();
150                                result.put(name, getParameterValues(name));
151                        }
152                        return result;
153                }
154
155                @Override
156                public Enumeration<String> getParameterNames() {
157                        Set<String> names = new LinkedHashSet<>();
158                        names.addAll(Collections.list(super.getParameterNames()));
159                        names.addAll(this.formParams.keySet());
160                        return Collections.enumeration(names);
161                }
162
163                @Override
164                @Nullable
165                public String[] getParameterValues(String name) {
166                        String[] parameterValues = super.getParameterValues(name);
167                        List<String> formParam = this.formParams.get(name);
168                        if (formParam == null) {
169                                return parameterValues;
170                        }
171                        if (parameterValues == null || getQueryString() == null) {
172                                return StringUtils.toStringArray(formParam);
173                        }
174                        else {
175                                List<String> result = new ArrayList<>(parameterValues.length + formParam.size());
176                                result.addAll(Arrays.asList(parameterValues));
177                                result.addAll(formParam);
178                                return StringUtils.toStringArray(result);
179                        }
180                }
181        }
182
183}