org.springframework.web.servlet.resource

Class ResourceHttpRequestHandler

java.lang.Object

org.springframework.context.support.ApplicationObjectSupport

org.springframework.web.context.support.WebApplicationObjectSupport

org.springframework.web.servlet.support.WebContentGenerator

org.springframework.web.servlet.resource.ResourceHttpRequestHandler

All Implemented Interfaces:

Aware, InitializingBean, ApplicationContextAware, ServletContextAware, CorsConfigurationSource, HttpRequestHandler

public class ResourceHttpRequestHandler
extends WebContentGenerator
implements HttpRequestHandler, InitializingBean, CorsConfigurationSource

HttpRequestHandler that serves static resources in an optimized way according to the guidelines of Page Speed, YSlow, etc.

The "locations" property takes a list of Spring 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.

This request handler may also be configured with a resourcesResolver and resourceTransformer chains to support arbitrary resolution and transformation of resources being served. By default a PathResourceResolver simply finds resources based on the configured "locations". An application can configure additional resolvers and transformers such as the VersionResourceResolver which can resolve and prepare URLs for resources with a version in the URL.

This handler also properly evaluates the Last-Modified header (if present) so that a 304 status code will be returned as appropriate, avoiding unnecessary overhead for resources that are already cached by the client.

Since:

3.0.4

Author:

Keith Donald, Jeremy Grelle, Juergen Hoeller, Arjen Poutsma, Brian Clozel, Rossen Stoyanchev

Field Summary

Fields inherited from class org.springframework.web.servlet.support.WebContentGenerator

HEADER_CACHE_CONTROL, METHOD_GET, METHOD_HEAD, METHOD_POST

Constructor Summary

Constructors

Constructor and Description
ResourceHttpRequestHandler()

Method Summary

Modifier and Type	Method and Description
void	afterPropertiesSet() Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).
ContentNegotiationManager	getContentNegotiationManager() Return the specified content negotiation manager.
CorsConfiguration	getCorsConfiguration(HttpServletRequest request) Return the specified CORS configuration.
List<Resource>	getLocations() Return the List of Resource paths to use as sources for serving static resources.
protected MediaType	getMediaType(HttpServletRequest request, Resource resource) Determine the media type for the given request and the resource matched to it.
protected MediaType	getMediaType(Resource resource) Deprecated. as of 4.3 this method is deprecated; please override getMediaType(HttpServletRequest, Resource) instead.
protected Resource	getResource(HttpServletRequest request)
ResourceHttpMessageConverter	getResourceHttpMessageConverter() Return the list of configured resource converters.
ResourceRegionHttpMessageConverter	getResourceRegionHttpMessageConverter() Return the list of configured resource region converters.
List<ResourceResolver>	getResourceResolvers() Return the list of configured resource resolvers.
List<ResourceTransformer>	getResourceTransformers() Return the list of configured resource transformers.
void	handleRequest(HttpServletRequest request, HttpServletResponse response) Processes a resource request.
protected void	initAllowedLocations() Look for a PathResourceResolver among the configured resource resolvers and set its allowedLocations property (if empty) to match the locations configured on this class.
protected void	initServletContext(ServletContext servletContext) Subclasses may override this for custom initialization based on the ServletContext that this application object runs in.
protected boolean	isInvalidPath(String path) Identifies invalid resource paths.
protected String	processPath(String path) Process the given resource path to be used.
void	setContentNegotiationManager(ContentNegotiationManager contentNegotiationManager) Configure a ContentNegotiationManager to determine the media types for resources being served.
void	setCorsConfiguration(CorsConfiguration corsConfiguration) Specify the CORS configuration for resources served by this handler.
protected void	setHeaders(HttpServletResponse response, Resource resource, MediaType mediaType) Set headers on the given servlet response.
void	setLocations(List<Resource> locations) Set the List of Resource paths to use as sources for serving static resources.
void	setResourceHttpMessageConverter(ResourceHttpMessageConverter resourceHttpMessageConverter) Configure the ResourceHttpMessageConverter to use.
void	setResourceRegionHttpMessageConverter(ResourceRegionHttpMessageConverter resourceRegionHttpMessageConverter) Configure the ResourceRegionHttpMessageConverter to use.
void	setResourceResolvers(List<ResourceResolver> resourceResolvers) Configure the list of ResourceResolvers to use.
void	setResourceTransformers(List<ResourceTransformer> resourceTransformers) Configure the list of ResourceTransformers to use.
String	toString()

Methods inherited from class org.springframework.web.servlet.support.WebContentGenerator

applyCacheControl, applyCacheSeconds, applyCacheSeconds, cacheForSeconds, cacheForSeconds, checkAndPrepare, checkAndPrepare, checkRequest, getAllowHeader, getCacheControl, getCacheSeconds, getSupportedMethods, getVaryByRequestHeaders, isAlwaysMustRevalidate, isRequireSession, isUseCacheControlHeader, isUseCacheControlNoStore, isUseExpiresHeader, prepareResponse, preventCaching, setAlwaysMustRevalidate, setCacheControl, setCacheSeconds, setRequireSession, setSupportedMethods, setUseCacheControlHeader, setUseCacheControlNoStore, setUseExpiresHeader, setVaryByRequestHeaders

Methods inherited from class org.springframework.web.context.support.WebApplicationObjectSupport

getServletContext, getTempDir, getWebApplicationContext, initApplicationContext, isContextRequired, setServletContext

Methods inherited from class org.springframework.context.support.ApplicationObjectSupport

getApplicationContext, getMessageSourceAccessor, initApplicationContext, requiredContextClass, setApplicationContext

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ResourceHttpRequestHandler

public ResourceHttpRequestHandler()

Method Detail

setLocations

public void setLocations(List<Resource> locations)

Set the List of Resource paths to use as sources for serving static resources.

getLocations

public List<Resource> getLocations()

Return the List of Resource paths to use as sources for serving static resources.

setResourceResolvers

public void setResourceResolvers(List<ResourceResolver> resourceResolvers)

Configure the list of ResourceResolvers to use.

By default PathResourceResolver is configured. If using this property, it is recommended to add PathResourceResolver as the last resolver.

getResourceResolvers

public List<ResourceResolver> getResourceResolvers()

Return the list of configured resource resolvers.

setResourceTransformers

public void setResourceTransformers(List<ResourceTransformer> resourceTransformers)

Configure the list of ResourceTransformers to use.

By default no transformers are configured for use.

getResourceTransformers

public List<ResourceTransformer> getResourceTransformers()

Return the list of configured resource transformers.

setResourceHttpMessageConverter

public void setResourceHttpMessageConverter(ResourceHttpMessageConverter resourceHttpMessageConverter)

Configure the ResourceHttpMessageConverter to use.

By default a ResourceHttpMessageConverter will be configured.

Since:

4.3

getResourceHttpMessageConverter

public ResourceHttpMessageConverter getResourceHttpMessageConverter()

Return the list of configured resource converters.

Since:

4.3

setResourceRegionHttpMessageConverter

public void setResourceRegionHttpMessageConverter(ResourceRegionHttpMessageConverter resourceRegionHttpMessageConverter)

Configure the ResourceRegionHttpMessageConverter to use.

By default a ResourceRegionHttpMessageConverter will be configured.

Since:

4.3

getResourceRegionHttpMessageConverter

public ResourceRegionHttpMessageConverter getResourceRegionHttpMessageConverter()

Return the list of configured resource region converters.

Since:

4.3

setContentNegotiationManager

public void setContentNegotiationManager(ContentNegotiationManager contentNegotiationManager)

Configure a ContentNegotiationManager to determine the media types for resources being served. If the manager contains a path extension strategy it will be used to look up the file extension of resources being served via getMediaTypeForResource. If that fails the check is then expanded to use any configured content negotiation strategy against the request.

By default a ContentNegotiationManagerFactoryBean with default settings is used to create the manager. See the Javadoc of ContentNegotiationManagerFactoryBean for details

Parameters:

contentNegotiationManager - the manager to use

Since:

4.3

getContentNegotiationManager

public ContentNegotiationManager getContentNegotiationManager()

Return the specified content negotiation manager.

Since:

4.3

setCorsConfiguration

public void setCorsConfiguration(CorsConfiguration corsConfiguration)

Specify the CORS configuration for resources served by this handler.

By default this is not set in which allows cross-origin requests.

getCorsConfiguration

public CorsConfiguration getCorsConfiguration(HttpServletRequest request)

Return the specified CORS configuration.

Specified by:

getCorsConfiguration in interface CorsConfigurationSource

Returns:

the associated CorsConfiguration, or null if none

initServletContext

protected void initServletContext(ServletContext servletContext)

Description copied from class: WebApplicationObjectSupport

Subclasses may override this for custom initialization based on the ServletContext that this application object runs in.

The default implementation is empty. Called by WebApplicationObjectSupport.initApplicationContext(org.springframework.context.ApplicationContext) as well as WebApplicationObjectSupport.setServletContext(javax.servlet.ServletContext).

Overrides:

initServletContext in class WebApplicationObjectSupport

Parameters:

servletContext - the ServletContext that this application object runs in (never null)

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Description copied from interface: InitializingBean

Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).

This method allows the bean instance to perform initialization only possible when all bean properties have been set and to throw an exception in the event of misconfiguration.

Specified by:

afterPropertiesSet in interface InitializingBean

Throws:

Exception - in the event of misconfiguration (such as failure to set an essential property) or if initialization fails.

initAllowedLocations

protected void initAllowedLocations()

Look for a PathResourceResolver among the configured resource resolvers and set its allowedLocations property (if empty) to match the locations configured on this class.

handleRequest

public void handleRequest(HttpServletRequest request,
                          HttpServletResponse response)
                   throws ServletException,
                          IOException

Processes a resource request.

Checks for the existence of the requested resource in the configured list of locations. If the resource does not exist, a 404 response will be returned to the client. If the resource exists, the request will be checked for the presence of the Last-Modified header, and its value will be compared against the last-modified timestamp of the given resource, returning a 304 status code if the Last-Modified value is greater. If the resource is newer than the Last-Modified value, or the header is not present, the content resource of the resource will be written to the response with caching headers set to expire one year in the future.

Specified by:

handleRequest in interface HttpRequestHandler

Parameters:

request - current HTTP request

response - current HTTP response

Throws:

ServletException - in case of general errors

IOException - in case of I/O errors

getResource

protected Resource getResource(HttpServletRequest request)
                        throws IOException

Throws:

IOException

processPath

protected String processPath(String path)

Process the given resource path to be used.

The default implementation replaces any combination of leading '/' and control characters (00-1F and 7F) with a single "/" or "". For example " // /// //// foo/bar" becomes "/foo/bar".

Since:

3.2.12

isInvalidPath

protected boolean isInvalidPath(String path)

Identifies invalid resource paths. By default rejects:

• Paths that contain "WEB-INF" or "META-INF"
• Paths that contain "../" after a call to StringUtils.cleanPath(java.lang.String).
• Paths that represent a valid URL or would represent one after the leading slash is removed.

Note: this method assumes that leading, duplicate '/' or control characters (e.g. white space) have been trimmed so that the path starts predictably with a single '/' or does not have one.

Parameters:

path - the path to validate

Returns:

true if the path is invalid, false otherwise

getMediaType

protected MediaType getMediaType(HttpServletRequest request,
                                 Resource resource)

Determine the media type for the given request and the resource matched to it. This implementation first tries to determine the MediaType based strictly on the file extension of the Resource via PathExtensionContentNegotiationStrategy.getMediaTypeForResource(org.springframework.core.io.Resource) and then expands to check against the request via ContentNegotiationManager.resolveMediaTypes(org.springframework.web.context.request.NativeWebRequest).

Parameters:

request - the current request

resource - the resource to check

Returns:

the corresponding media type, or null if none found

getMediaType

@Deprecated
protected MediaType getMediaType(Resource resource)

Deprecated. as of 4.3 this method is deprecated; please override getMediaType(HttpServletRequest, Resource) instead.

Determine an appropriate media type for the given resource.

Parameters:

resource - the resource to check

Returns:

the corresponding media type, or null if none found

setHeaders

protected void setHeaders(HttpServletResponse response,
                          Resource resource,
                          MediaType mediaType)
                   throws IOException

Set headers on the given servlet response. Called for GET requests as well as HEAD requests.

Parameters:

response - current servlet response

resource - the identified resource (never null)

mediaType - the resource's media type (never null)

Throws:

IOException - in case of errors while setting the headers

toString

public String toString()

Overrides:

toString in class Object