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, EmbeddedValueResolverAware, ServletContextAware, CorsConfigurationSource, HttpRequestHandler

public class ResourceHttpRequestHandler
extends WebContentGenerator
implements HttpRequestHandler, EmbeddedValueResolverAware, 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 configured content negotiation manager.
CorsConfiguration	getCorsConfiguration(HttpServletRequest request) Return the specified CORS configuration.
java.util.List<Resource>	getLocations() Return the configured List of Resource locations.
protected MediaType	getMediaType(HttpServletRequest request, Resource resource) Determine the media type for the given request and the resource matched to it.
protected Resource	getResource(HttpServletRequest request)
ResourceHttpMessageConverter	getResourceHttpMessageConverter() Return the configured resource converter.
ResourceRegionHttpMessageConverter	getResourceRegionHttpMessageConverter() Return the configured resource region converter.
java.util.List<ResourceResolver>	getResourceResolvers() Return the list of configured resource resolvers.
java.util.List<ResourceTransformer>	getResourceTransformers() Return the list of configured resource transformers.
UrlPathHelper	getUrlPathHelper() The configured UrlPathHelper.
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 PathExtensionContentNegotiationStrategy	initContentNegotiationStrategy() Initialize the content negotiation strategy depending on the ContentNegotiationManager setup and the availability of a ServletContext.
protected boolean	isInvalidPath(java.lang.String path) Identifies invalid resource paths.
protected java.lang.String	processPath(java.lang.String path) Process the given resource path.
void	setContentNegotiationManager(ContentNegotiationManager contentNegotiationManager) Configure a ContentNegotiationManager to help determine the media types for resources being served.
void	setCorsConfiguration(CorsConfiguration corsConfiguration) Specify the CORS configuration for resources served by this handler.
void	setEmbeddedValueResolver(StringValueResolver resolver) Set the StringValueResolver to use for resolving embedded definition values.
protected void	setHeaders(HttpServletResponse response, Resource resource, MediaType mediaType) Set headers on the given servlet response.
void	setLocations(java.util.List<Resource> locations) Set the List of Resource locations to use as sources for serving static resources.
void	setLocationValues(java.util.List<java.lang.String> locationValues) An alternative to setLocations(List) that accepts a list of String-based location values, with support for UrlResource's (e.g.
void	setResourceHttpMessageConverter(ResourceHttpMessageConverter messageConverter) Configure the ResourceHttpMessageConverter to use.
void	setResourceRegionHttpMessageConverter(ResourceRegionHttpMessageConverter messageConverter) Configure the ResourceRegionHttpMessageConverter to use.
void	setResourceResolvers(java.util.List<ResourceResolver> resourceResolvers) Configure the list of ResourceResolvers to use.
void	setResourceTransformers(java.util.List<ResourceTransformer> resourceTransformers) Configure the list of ResourceTransformers to use.
void	setUrlPathHelper(UrlPathHelper urlPathHelper) Provide a reference to the UrlPathHelper used to map requests to static resources.
java.lang.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, initServletContext, isContextRequired, setServletContext

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

getApplicationContext, getMessageSourceAccessor, initApplicationContext, obtainApplicationContext, 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

setLocationValues

public void setLocationValues(java.util.List<java.lang.String> locationValues)

An alternative to setLocations(List) that accepts a list of String-based location values, with support for UrlResource's (e.g. files or HTTP URLs) with a special prefix to indicate the charset to use when appending relative paths. For example "[charset=Windows-31J]http://example.org/path".

Since:

4.3.13

setLocations

public void setLocations(java.util.List<Resource> locations)

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

See Also:

setLocationValues(List)

getLocations

public java.util.List<Resource> getLocations()

Return the configured List of Resource locations.

Note that if locationValues are provided, instead of loaded Resource-based locations, this method will return empty until after initialization via afterPropertiesSet().

See Also:

setLocationValues(java.util.List<java.lang.String>), setLocations(java.util.List<org.springframework.core.io.Resource>)

setResourceResolvers

public void setResourceResolvers(@Nullable
                                 java.util.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 java.util.List<ResourceResolver> getResourceResolvers()

Return the list of configured resource resolvers.

setResourceTransformers

public void setResourceTransformers(@Nullable
                                    java.util.List<ResourceTransformer> resourceTransformers)

Configure the list of ResourceTransformers to use.

By default no transformers are configured for use.

getResourceTransformers

public java.util.List<ResourceTransformer> getResourceTransformers()

Return the list of configured resource transformers.

setResourceHttpMessageConverter

public void setResourceHttpMessageConverter(@Nullable
                                            ResourceHttpMessageConverter messageConverter)

Configure the ResourceHttpMessageConverter to use.

By default a ResourceHttpMessageConverter will be configured.

Since:

4.3

getResourceHttpMessageConverter

@Nullable
public ResourceHttpMessageConverter getResourceHttpMessageConverter()

Return the configured resource converter.

Since:

4.3

setResourceRegionHttpMessageConverter

public void setResourceRegionHttpMessageConverter(@Nullable
                                                  ResourceRegionHttpMessageConverter messageConverter)

Configure the ResourceRegionHttpMessageConverter to use.

By default a ResourceRegionHttpMessageConverter will be configured.

Since:

4.3

getResourceRegionHttpMessageConverter

@Nullable
public ResourceRegionHttpMessageConverter getResourceRegionHttpMessageConverter()

Return the configured resource region converter.

Since:

4.3

setContentNegotiationManager

public void setContentNegotiationManager(@Nullable
                                         ContentNegotiationManager contentNegotiationManager)

Configure a ContentNegotiationManager to help determine the media types for resources being served. If the manager contains a path extension strategy it will be checked for registered file extension.

Since:

4.3

getContentNegotiationManager

@Nullable
public ContentNegotiationManager getContentNegotiationManager()

Return the configured 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

@Nullable
public CorsConfiguration getCorsConfiguration(HttpServletRequest request)

Return the specified CORS configuration.

Specified by:

getCorsConfiguration in interface CorsConfigurationSource

Returns:

the associated CorsConfiguration, or null if none

setUrlPathHelper

public void setUrlPathHelper(@Nullable
                             UrlPathHelper urlPathHelper)

Provide a reference to the UrlPathHelper used to map requests to static resources. This helps to derive information about the lookup path such as whether it is decoded or not.

Since:

4.3.13

getUrlPathHelper

@Nullable
public UrlPathHelper getUrlPathHelper()

The configured UrlPathHelper.

Since:

4.3.13

setEmbeddedValueResolver

public void setEmbeddedValueResolver(StringValueResolver resolver)

Description copied from interface: EmbeddedValueResolverAware

Set the StringValueResolver to use for resolving embedded definition values.

Specified by:

setEmbeddedValueResolver in interface EmbeddedValueResolverAware

afterPropertiesSet

public void afterPropertiesSet()
                        throws java.lang.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:

java.lang.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.

initContentNegotiationStrategy

protected PathExtensionContentNegotiationStrategy initContentNegotiationStrategy()

Initialize the content negotiation strategy depending on the ContentNegotiationManager setup and the availability of a ServletContext.

See Also:

ServletPathExtensionContentNegotiationStrategy, PathExtensionContentNegotiationStrategy

handleRequest

public void handleRequest(HttpServletRequest request,
                          HttpServletResponse response)
                   throws ServletException,
                          java.io.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

java.io.IOException - in case of I/O errors

getResource

@Nullable
protected Resource getResource(HttpServletRequest request)
                                  throws java.io.IOException

Throws:

java.io.IOException

processPath

protected java.lang.String processPath(java.lang.String path)

Process the given resource path.

The default implementation replaces:

• Backslash with forward slash.
• Duplicate occurrences of slash with a single slash.
• Any combination of leading slash 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(java.lang.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

Since:

3.0.6

getMediaType

@Nullable
protected MediaType getMediaType(HttpServletRequest request,
                                           Resource resource)

Determine the media type for the given request and the resource matched to it. This implementation tries to determine the MediaType based on the file extension of the Resource via ServletPathExtensionContentNegotiationStrategy.getMediaTypeForResource(org.springframework.core.io.Resource).

Parameters:

request - the current request

resource - the resource to check

Returns:

the corresponding media type, or null if none found

setHeaders

protected void setHeaders(HttpServletResponse response,
                          Resource resource,
                          @Nullable
                          MediaType mediaType)
                   throws java.io.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:

java.io.IOException - in case of errors while setting the headers

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object