001/*
002 * Copyright 2002-2019 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.multipart.support;
018
019import java.util.ArrayList;
020import java.util.Collection;
021import java.util.List;
022
023import javax.servlet.http.HttpServletRequest;
024import javax.servlet.http.Part;
025
026import org.springframework.core.MethodParameter;
027import org.springframework.core.ResolvableType;
028import org.springframework.lang.Nullable;
029import org.springframework.web.context.request.NativeWebRequest;
030import org.springframework.web.multipart.MultipartFile;
031import org.springframework.web.multipart.MultipartHttpServletRequest;
032import org.springframework.web.multipart.MultipartRequest;
033import org.springframework.web.util.WebUtils;
034
035/**
036 * A common delegate for {@code HandlerMethodArgumentResolver} implementations
037 * which need to resolve {@link MultipartFile} and {@link Part} arguments.
038 *
039 * @author Juergen Hoeller
040 * @since 4.3
041 */
042public final class MultipartResolutionDelegate {
043
044        /**
045         * Indicates an unresolvable value.
046         */
047        public static final Object UNRESOLVABLE = new Object();
048
049
050        private MultipartResolutionDelegate() {
051        }
052
053
054        @Nullable
055        public static MultipartRequest resolveMultipartRequest(NativeWebRequest webRequest) {
056                MultipartRequest multipartRequest = webRequest.getNativeRequest(MultipartRequest.class);
057                if (multipartRequest != null) {
058                        return multipartRequest;
059                }
060                HttpServletRequest servletRequest = webRequest.getNativeRequest(HttpServletRequest.class);
061                if (servletRequest != null && isMultipartContent(servletRequest)) {
062                        return new StandardMultipartHttpServletRequest(servletRequest);
063                }
064                return null;
065        }
066
067        public static boolean isMultipartRequest(HttpServletRequest request) {
068                return (WebUtils.getNativeRequest(request, MultipartHttpServletRequest.class) != null ||
069                                isMultipartContent(request));
070        }
071
072        private static boolean isMultipartContent(HttpServletRequest request) {
073                String contentType = request.getContentType();
074                return (contentType != null && contentType.toLowerCase().startsWith("multipart/"));
075        }
076
077        static MultipartHttpServletRequest asMultipartHttpServletRequest(HttpServletRequest request) {
078                MultipartHttpServletRequest unwrapped = WebUtils.getNativeRequest(request, MultipartHttpServletRequest.class);
079                if (unwrapped != null) {
080                        return unwrapped;
081                }
082                return new StandardMultipartHttpServletRequest(request);
083        }
084
085
086        public static boolean isMultipartArgument(MethodParameter parameter) {
087                Class<?> paramType = parameter.getNestedParameterType();
088                return (MultipartFile.class == paramType ||
089                                isMultipartFileCollection(parameter) || isMultipartFileArray(parameter) ||
090                                (Part.class == paramType || isPartCollection(parameter) || isPartArray(parameter)));
091        }
092
093        @Nullable
094        public static Object resolveMultipartArgument(String name, MethodParameter parameter, HttpServletRequest request)
095                        throws Exception {
096
097                MultipartHttpServletRequest multipartRequest =
098                                WebUtils.getNativeRequest(request, MultipartHttpServletRequest.class);
099                boolean isMultipart = (multipartRequest != null || isMultipartContent(request));
100
101                if (MultipartFile.class == parameter.getNestedParameterType()) {
102                        if (multipartRequest == null && isMultipart) {
103                                multipartRequest = new StandardMultipartHttpServletRequest(request);
104                        }
105                        return (multipartRequest != null ? multipartRequest.getFile(name) : null);
106                }
107                else if (isMultipartFileCollection(parameter)) {
108                        if (multipartRequest == null && isMultipart) {
109                                multipartRequest = new StandardMultipartHttpServletRequest(request);
110                        }
111                        return (multipartRequest != null ? multipartRequest.getFiles(name) : null);
112                }
113                else if (isMultipartFileArray(parameter)) {
114                        if (multipartRequest == null && isMultipart) {
115                                multipartRequest = new StandardMultipartHttpServletRequest(request);
116                        }
117                        if (multipartRequest != null) {
118                                List<MultipartFile> multipartFiles = multipartRequest.getFiles(name);
119                                return multipartFiles.toArray(new MultipartFile[0]);
120                        }
121                        else {
122                                return null;
123                        }
124                }
125                else if (Part.class == parameter.getNestedParameterType()) {
126                        return (isMultipart ? request.getPart(name): null);
127                }
128                else if (isPartCollection(parameter)) {
129                        return (isMultipart ? resolvePartList(request, name) : null);
130                }
131                else if (isPartArray(parameter)) {
132                        return (isMultipart ? resolvePartList(request, name).toArray(new Part[0]) : null);
133                }
134                else {
135                        return UNRESOLVABLE;
136                }
137        }
138
139        private static boolean isMultipartFileCollection(MethodParameter methodParam) {
140                return (MultipartFile.class == getCollectionParameterType(methodParam));
141        }
142
143        private static boolean isMultipartFileArray(MethodParameter methodParam) {
144                return (MultipartFile.class == methodParam.getNestedParameterType().getComponentType());
145        }
146
147        private static boolean isPartCollection(MethodParameter methodParam) {
148                return (Part.class == getCollectionParameterType(methodParam));
149        }
150
151        private static boolean isPartArray(MethodParameter methodParam) {
152                return (Part.class == methodParam.getNestedParameterType().getComponentType());
153        }
154
155        @Nullable
156        private static Class<?> getCollectionParameterType(MethodParameter methodParam) {
157                Class<?> paramType = methodParam.getNestedParameterType();
158                if (Collection.class == paramType || List.class.isAssignableFrom(paramType)){
159                        Class<?> valueType = ResolvableType.forMethodParameter(methodParam).asCollection().resolveGeneric();
160                        if (valueType != null) {
161                                return valueType;
162                        }
163                }
164                return null;
165        }
166
167        private static List<Part> resolvePartList(HttpServletRequest request, String name) throws Exception {
168                Collection<Part> parts = request.getParts();
169                List<Part> result = new ArrayList<>(parts.size());
170                for (Part part : parts) {
171                        if (part.getName().equals(name)) {
172                                result.add(part);
173                        }
174                }
175                return result;
176        }
177
178}