/*
* Copyright 2002-2012 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.ClassUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.util.UrlPathHelper;
import org.springframework.web.util.WebUtils;
/**
* A ContentNegotiationStrategy that uses the path extension of the URL to
* determine what media types are requested. The path extension is first looked
* up in the map of media types provided to the constructor. If that fails, the
* Java Activation framework is used as a fallback mechanism.
*
* <p>
* The presence of the Java Activation framework is detected and enabled
* automatically but the {@link #setUseJaf(boolean)} property may be used to
* override that setting.
*
* @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 static final UrlPathHelper urlPathHelper = new UrlPathHelper();
static {
urlPathHelper.setUrlDecode(false);
}
private boolean useJaf = JAF_PRESENT;
/**
* Create an instance with the given extension-to-MediaType lookup.
* @throws IllegalArgumentException if a media type string cannot be parsed
*/
public PathExtensionContentNegotiationStrategy(Map<String, MediaType> mediaTypes) {
super(mediaTypes);
}
/**
* 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() {
super(null);
}
/**
* Indicate whether to use the Java Activation Framework to map from file extensions to media types.
* <p>Default is {@code true}, i.e. the Java Activation Framework is used (if available).
*/
public void setUseJaf(boolean useJaf) {
this.useJaf = useJaf;
}
@Override
protected String getMediaTypeKey(NativeWebRequest webRequest) {
HttpServletRequest servletRequest = webRequest.getNativeRequest(HttpServletRequest.class);
if (servletRequest == null) {
logger.warn("An HttpServletRequest is required to determine the media type key");
return null;
}
String path = urlPathHelper.getLookupPathForRequest(servletRequest);
String filename = WebUtils.extractFullFilenameFromUrlPath(path);
String extension = StringUtils.getFilenameExtension(filename);
return (StringUtils.hasText(extension)) ? extension.toLowerCase(Locale.ENGLISH) : null;
}
@Override
protected void handleMatch(String extension, MediaType mediaType) {
}
@Override
protected MediaType handleNoMatch(NativeWebRequest webRequest, String extension) {
if (this.useJaf) {
MediaType jafMediaType = JafMediaTypeFactory.getMediaType("file." + extension);
if (jafMediaType != null && !MediaType.APPLICATION_OCTET_STREAM.equals(jafMediaType)) {
return jafMediaType;
}
}
return null;
}
/**
* Inner class to avoid hard-coded dependency on JAF.
*/
private static class JafMediaTypeFactory {
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 Java Activation Framework 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);
}
}
}