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/*
 * Copyright 2002-2017 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
 *
 *      http://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.accept;

import java.io.IOException;
import java.io.InputStream;
import java.util.Locale;
import java.util.Map;
import javax.activation.FileTypeMap;
import javax.activation.MimetypesFileTypeMap;
import javax.servlet.http.HttpServletRequest;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.http.MediaType;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.HttpMediaTypeNotAcceptableException;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.util.UriUtils;
import org.springframework.web.util.UrlPathHelper;

/**
 * A {@code ContentNegotiationStrategy} that resolves the file extension in the
 * request path to a key to be used to look up a media type.
 *
 * 

If the file extension is not found in the explicit registrations provided * to the constructor, the Java Activation Framework (JAF) is used as a fallback * mechanism. * *

The presence of the JAF is detected and enabled automatically but the * {@link #setUseJaf(boolean)} property may be set to false. * * @author Rossen Stoyanchev * @since 3.2 */ public class PathExtensionContentNegotiationStrategy extends AbstractMappingContentNegotiationStrategy { private static final boolean JAF_PRESENT = ClassUtils.isPresent("javax.activation.FileTypeMap", PathExtensionContentNegotiationStrategy.class.getClassLoader()); private static final Log logger = LogFactory.getLog(PathExtensionContentNegotiationStrategy.class); private UrlPathHelper urlPathHelper = new UrlPathHelper(); private boolean useJaf = true; private boolean ignoreUnknownExtensions = true; /** * Create an instance without any mappings to start with. Mappings may be added * later on if any extensions are resolved through the Java Activation framework. */ public PathExtensionContentNegotiationStrategy() { this(null); } /** * Create an instance with the given map of file extensions and media types. */ public PathExtensionContentNegotiationStrategy(Map mediaTypes) { super(mediaTypes); this.urlPathHelper.setUrlDecode(false); } /** * Configure a {@code UrlPathHelper} to use in {@link #getMediaTypeKey} * in order to derive the lookup path for a target request URL path. * @since 4.2.8 */ public void setUrlPathHelper(UrlPathHelper urlPathHelper) { this.urlPathHelper = urlPathHelper; } /** * Whether to use the Java Activation Framework to look up file extensions. *

By default this is set to "true" but depends on JAF being present. */ public void setUseJaf(boolean useJaf) { this.useJaf = useJaf; } /** * Whether to ignore requests with unknown file extension. Setting this to * {@code false} results in {@code HttpMediaTypeNotAcceptableException}. *

By default this is set to {@code true}. */ public void setIgnoreUnknownExtensions(boolean ignoreUnknownExtensions) { this.ignoreUnknownExtensions = ignoreUnknownExtensions; } @Override protected String getMediaTypeKey(NativeWebRequest webRequest) { HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class); if (request == null) { logger.warn("An HttpServletRequest is required to determine the media type key"); return null; } String path = this.urlPathHelper.getLookupPathForRequest(request); String extension = UriUtils.extractFileExtension(path); return (StringUtils.hasText(extension) ? extension.toLowerCase(Locale.ENGLISH) : null); } @Override protected MediaType handleNoMatch(NativeWebRequest webRequest, String extension) throws HttpMediaTypeNotAcceptableException { if (this.useJaf && JAF_PRESENT) { MediaType mediaType = ActivationMediaTypeFactory.getMediaType("file." + extension); if (mediaType != null && !MediaType.APPLICATION_OCTET_STREAM.equals(mediaType)) { return mediaType; } } if (this.ignoreUnknownExtensions) { return null; } throw new HttpMediaTypeNotAcceptableException(getAllMediaTypes()); } /** * A public method exposing the knowledge of the path extension strategy to * resolve file extensions to a {@link MediaType} in this case for a given * {@link Resource}. The method first looks up any explicitly registered * file extensions first and then falls back on JAF if available. * @param resource the resource to look up * @return the MediaType for the extension, or {@code null} if none found * @since 4.3 */ public MediaType getMediaTypeForResource(Resource resource) { Assert.notNull(resource, "Resource must not be null"); MediaType mediaType = null; String filename = resource.getFilename(); String extension = StringUtils.getFilenameExtension(filename); if (extension != null) { mediaType = lookupMediaType(extension); } if (mediaType == null && JAF_PRESENT) { mediaType = ActivationMediaTypeFactory.getMediaType(filename); } if (MediaType.APPLICATION_OCTET_STREAM.equals(mediaType)) { mediaType = null; } return mediaType; } /** * Inner class to avoid hard-coded dependency on JAF. */ private static class ActivationMediaTypeFactory { private static final FileTypeMap fileTypeMap; static { fileTypeMap = initFileTypeMap(); } /** * Find extended mime.types from the spring-context-support module. */ private static FileTypeMap initFileTypeMap() { Resource resource = new ClassPathResource("org/springframework/mail/javamail/mime.types"); if (resource.exists()) { if (logger.isTraceEnabled()) { logger.trace("Loading JAF FileTypeMap from " + resource); } InputStream inputStream = null; try { inputStream = resource.getInputStream(); return new MimetypesFileTypeMap(inputStream); } catch (IOException ex) { // ignore } finally { if (inputStream != null) { try { inputStream.close(); } catch (IOException ex) { // ignore } } } } if (logger.isTraceEnabled()) { logger.trace("Loading default Java Activation Framework FileTypeMap"); } return FileTypeMap.getDefaultFileTypeMap(); } public static MediaType getMediaType(String filename) { String mediaType = fileTypeMap.getContentType(filename); return (StringUtils.hasText(mediaType) ? MediaType.parseMediaType(mediaType) : null); } } }





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