001/*
002 * Copyright 2002-2017 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 */
016package org.springframework.web.reactive.accept;
017
018import java.util.ArrayList;
019import java.util.Collections;
020import java.util.List;
021import java.util.Locale;
022import java.util.Map;
023import java.util.concurrent.ConcurrentHashMap;
024
025import org.springframework.http.MediaType;
026import org.springframework.http.MediaTypeFactory;
027import org.springframework.util.Assert;
028import org.springframework.util.StringUtils;
029import org.springframework.web.server.NotAcceptableStatusException;
030import org.springframework.web.server.ServerWebExchange;
031
032/**
033 * Resolver that checks a query parameter and uses it to lookup a matching
034 * MediaType. Lookup keys can be registered or as a fallback
035 * {@link MediaTypeFactory} can be used to perform a lookup.
036 *
037 * @author Rossen Stoyanchev
038 * @since 5.0
039 */
040public class ParameterContentTypeResolver implements RequestedContentTypeResolver {
041
042        /** Primary lookup for media types by key (e.g. "json" -> "application/json") */
043        private final Map<String, MediaType> mediaTypes = new ConcurrentHashMap<>(64);
044
045        private String parameterName = "format";
046
047
048        public ParameterContentTypeResolver(Map<String, MediaType> mediaTypes) {
049                mediaTypes.forEach((key, value) -> this.mediaTypes.put(formatKey(key), value));
050        }
051
052        private static String formatKey(String key) {
053                return key.toLowerCase(Locale.ENGLISH);
054        }
055
056
057        /**
058         * Set the name of the parameter to use to determine requested media types.
059         * <p>By default this is set to {@literal "format"}.
060         */
061        public void setParameterName(String parameterName) {
062                Assert.notNull(parameterName, "'parameterName' is required");
063                this.parameterName = parameterName;
064        }
065
066        public String getParameterName() {
067                return this.parameterName;
068        }
069
070
071        @Override
072        public List<MediaType> resolveMediaTypes(ServerWebExchange exchange) throws NotAcceptableStatusException {
073                String key = exchange.getRequest().getQueryParams().getFirst(getParameterName());
074                if (!StringUtils.hasText(key)) {
075                        return MEDIA_TYPE_ALL_LIST;
076                }
077                key = formatKey(key);
078                MediaType match = this.mediaTypes.get(key);
079                if (match == null) {
080                        match = MediaTypeFactory.getMediaType("filename." + key)
081                                        .orElseThrow(() -> {
082                                                List<MediaType> supported = new ArrayList<>(this.mediaTypes.values());
083                                                return new NotAcceptableStatusException(supported);
084                                        });
085                }
086                this.mediaTypes.putIfAbsent(key, match);
087                return Collections.singletonList(match);
088        }
089
090}