Spring/spring-framework
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Polish static resource handling

Browse Source
This commit is contained in:
Rossen Stoyanchev
2016-03-04 11:51:30 -05:00
parent 5067f00228
commit 1a76f7e9c2
2 changed files with 57 additions and 69 deletions
Download Patch File Download Diff File Expand all files Collapse all files

61
spring-webmvc/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java
View File

@@ -57,40 +57,35 @@ import org.springframework.web.servlet.HandlerMapping;
import org.springframework.web.servlet.support.WebContentGenerator;
/**
* {@link HttpRequestHandler} that serves static resources optimized for superior browser performance
* (according to the guidelines of Page Speed, YSlow, etc.) by allowing for flexible cache settings
* ({@linkplain #setCacheSeconds "cacheSeconds" property}, last-modified support).
* {@code HttpRequestHandler} that serves static resources in an optimized way
* according to the guidelines of Page Speed, YSlow, etc.
*
* <p>The {@linkplain #setLocations "locations" property} takes a list of Spring {@link Resource}
* locations from which static resources are allowed to be served by this handler. For a given request,
* the list of locations will be consulted in order for the presence of the requested resource, and the
* first found match will be written to the response, with a HTTP Caching headers
* set as configured. The handler also properly evaluates the {@code Last-Modified} header
* (if present) so that a {@code 304} status code will be returned as appropriate, avoiding unnecessary
* overhead for resources that are already cached by the client. The use of {@code Resource} locations
* allows resource requests to easily be mapped to locations other than the web application root.
* For example, resources could be served from a classpath location such as
* "classpath:/META-INF/public-web-resources/", allowing convenient packaging and serving of resources
* such as a JavaScript library from within jar files.
* <p>The {@linkplain #setLocations "locations"} property takes a list of Spring
* {@link Resource} locations from which static resources are allowed to
* be served by this handler. Resources could be served from a classpath location,
* e.g. "classpath:/META-INF/public-web-resources/", allowing convenient packaging
* and serving of resources such as .js, .css, and others in jar files.
*
* <p>To ensure that users with a primed browser cache get the latest changes to application-specific
* resources upon deployment of new versions of the application, it is recommended that a version
* string is used in the URL mapping pattern that selects this handler. Such patterns can be easily
* parameterized using Spring EL. See the reference manual for further examples of this approach.
* <p>This request handler may also be configured with a
* {@link #setResourceResolvers(List) resourcesResolver} and
* {@link #setResourceTransformers(List) resourceTransformer} chains to support
* arbitrary resolution and transformation of resources being served. By default a
* {@link PathResourceResolver} simply finds resources based on the configured
* "locations". An application can configure additional resolvers and
* transformers such as the {@link VersionResourceResolver} which can resolve
* and prepare URLs for resources with a version in the URL.
*
* <p>For various front-end needs &mdash; such as ensuring that users with a primed browser cache
* get the latest changes, or serving variations of resources (e.g., minified versions) &mdash;
* {@link org.springframework.web.servlet.resource.ResourceResolver}s can be configured.
*
* <p>This handler can be configured through use of a
* {@link org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry}
* or the {@code <mvc:resources/>} XML configuration element.
* <p>This handler also properly evaluates the {@code Last-Modified} header (if
* present) so that a {@code 304} status code will be returned as appropriate,
* avoiding unnecessary overhead for resources that are already cached by the
* client.
*
* @author Keith Donald
* @author Jeremy Grelle
* @author Juergen Hoeller
* @author Arjen Poutsma
* @author Brian Clozel
* @author Rossen Stoyanchev
* @since 3.0.4
*/
public class ResourceHttpRequestHandler extends WebContentGenerator
@@ -113,7 +108,6 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
public ResourceHttpRequestHandler() {
super(HttpMethod.GET.name(), HttpMethod.HEAD.name());
this.resourceResolvers.add(new PathResourceResolver());
}
@@ -168,6 +162,10 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
return this.resourceTransformers;
}
/**
* Specify the CORS configuration for resources served by this handler.
* <p>By default this is not set in which allows cross-origin requests.
*/
public void setCorsConfiguration(CorsConfiguration corsConfiguration) {
this.corsConfiguration = corsConfiguration;
}
@@ -184,15 +182,16 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
logger.warn("Locations list is empty. No resources will be served unless a " +
"custom ResourceResolver is configured as an alternative to PathResourceResolver.");
}
if (this.resourceResolvers.isEmpty()) {
this.resourceResolvers.add(new PathResourceResolver());
}
initAllowedLocations();
}
/**
* Look for a {@link org.springframework.web.servlet.resource.PathResourceResolver}
* among the {@link #getResourceResolvers() resource resolvers} and configure
* its {@code "allowedLocations"} to match the value of the
* {@link #setLocations(java.util.List) locations} property unless the "allowed
* locations" of the {@code PathResourceResolver} is non-empty.
* Look for a {@code PathResourceResolver} among the configured resource
* resolvers and set its {@code allowedLocations} property (if empty) to
* match the {@link #setLocations locations} configured on this class.
*/
protected void initAllowedLocations() {
if (CollectionUtils.isEmpty(this.locations)) {