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.accept;
018
019import java.util.Map;
020
021import org.springframework.http.MediaType;
022import org.springframework.lang.Nullable;
023import org.springframework.util.Assert;
024import org.springframework.web.context.request.NativeWebRequest;
025
026/**
027 * Strategy that resolves the requested content type from a query parameter.
028 * The default query parameter name is {@literal "format"}.
029 *
030 * <p>You can register static mappings between keys (i.e. the expected value of
031 * the query parameter) and MediaType's via {@link #addMapping(String, MediaType)}.
032 * As of 5.0 this strategy also supports dynamic lookups of keys via
033 * {@link org.springframework.http.MediaTypeFactory#getMediaType}.
034 *
035 * @author Rossen Stoyanchev
036 * @since 3.2
037 */
038public class ParameterContentNegotiationStrategy extends AbstractMappingContentNegotiationStrategy {
039
040        private String parameterName = "format";
041
042
043        /**
044         * Create an instance with the given map of file extensions and media types.
045         */
046        public ParameterContentNegotiationStrategy(Map<String, MediaType> mediaTypes) {
047                super(mediaTypes);
048        }
049
050
051        /**
052         * Set the name of the parameter to use to determine requested media types.
053         * <p>By default this is set to {@code "format"}.
054         */
055        public void setParameterName(String parameterName) {
056                Assert.notNull(parameterName, "'parameterName' is required");
057                this.parameterName = parameterName;
058        }
059
060        public String getParameterName() {
061                return this.parameterName;
062        }
063
064
065        @Override
066        @Nullable
067        protected String getMediaTypeKey(NativeWebRequest request) {
068                return request.getParameter(getParameterName());
069        }
070
071}