org.springframework.web.accept.PathExtensionContentNegotiationStrategy Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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.util.Locale;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import org.springframework.core.io.Resource;
import org.springframework.http.MediaType;
import org.springframework.http.MediaTypeFactory;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
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 {@link MediaTypeFactory} is used as a fallback
* mechanism.
*
* @author Rossen Stoyanchev
* @since 3.2
*/
public class PathExtensionContentNegotiationStrategy extends AbstractMappingContentNegotiationStrategy {
private UrlPathHelper urlPathHelper = new UrlPathHelper();
/**
* 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(@Nullable Map mediaTypes) {
super(mediaTypes);
setUseRegisteredExtensionsOnly(false);
setIgnoreUnknownExtensions(true);
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;
}
/**
* Indicate whether to use the Java Activation Framework as a fallback option
* to map from file extensions to media types.
* @deprecated as of 5.0, in favor of {@link #setUseRegisteredExtensionsOnly(boolean)}.
*/
@Deprecated
public void setUseJaf(boolean useJaf) {
setUseRegisteredExtensionsOnly(!useJaf);
}
@Override
@Nullable
protected String getMediaTypeKey(NativeWebRequest webRequest) {
HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class);
if (request == null) {
return null;
}
String path = this.urlPathHelper.getLookupPathForRequest(request);
String extension = UriUtils.extractFileExtension(path);
return (StringUtils.hasText(extension) ? extension.toLowerCase(Locale.ENGLISH) : null);
}
/**
* 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 {@link MediaTypeFactory} if available.
* @param resource the resource to look up
* @return the MediaType for the extension, or {@code null} if none found
* @since 4.3
*/
@Nullable
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) {
mediaType = MediaTypeFactory.getMediaType(filename).orElse(null);
}
return mediaType;
}
}