org.springframework.web.servlet.resource

Class VersionResourceResolver

java.lang.Object

org.springframework.web.servlet.resource.AbstractResourceResolver

org.springframework.web.servlet.resource.VersionResourceResolver

All Implemented Interfaces:

ResourceResolver

public class VersionResourceResolver
extends AbstractResourceResolver

Resolves request paths containing a version string that can be used as part of an HTTP caching strategy in which a resource is cached with a date in the distant future (e.g. 1 year) and cached until the version, and therefore the URL, is changed.

Different versioning strategies exist, and this resolver must be configured with one or more such strategies along with path mappings to indicate which strategy applies to which resources.

ContentVersionStrategy is a good default choice except in cases where it cannot be used. Most notably the ContentVersionStrategy cannot be combined with JavaScript module loaders. For such cases the FixedVersionStrategy is a better choice.

Note that using this resolver to serve CSS files means that the CssLinkResourceTransformer should also be used in order to modify links within CSS files to also contain the appropriate versions generated by this resolver.

Since:

4.1

Author:

Brian Clozel, Rossen Stoyanchev

See Also:

VersionStrategy

Field Summary

Fields inherited from class org.springframework.web.servlet.resource.AbstractResourceResolver

logger

Constructor Summary

Constructors

Constructor and Description
VersionResourceResolver()

Method Summary

Modifier and Type	Method and Description
VersionResourceResolver	addContentVersionStrategy(String... pathPatterns) Insert a content-based version in resource URLs that match the given path patterns.
VersionResourceResolver	addFixedVersionStrategy(String version, String... pathPatterns) Insert a fixed, prefix-based version in resource URLs that match the given path patterns, for example: "{version}/js/main.js".
VersionResourceResolver	addVersionStrategy(VersionStrategy strategy, String... pathPatterns) Register a custom VersionStrategy to apply to resource URLs that match the given path patterns.
protected VersionStrategy	getStrategyForPath(String requestPath) Find a VersionStrategy for the request path of the requested resource.
Map<String,VersionStrategy>	getStrategyMap() Return the map with version strategies keyed by path pattern.
protected Resource	resolveResourceInternal(HttpServletRequest request, String requestPath, List<? extends Resource> locations, ResourceResolverChain chain)
protected String	resolveUrlPathInternal(String resourceUrlPath, List<? extends Resource> locations, ResourceResolverChain chain)
void	setStrategyMap(Map<String,VersionStrategy> map) Set a Map with URL paths as keys and VersionStrategy as values.

Methods inherited from class org.springframework.web.servlet.resource.AbstractResourceResolver

resolveResource, resolveUrlPath

Methods inherited from class java.lang.Object

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

Constructor Detail

VersionResourceResolver

public VersionResourceResolver()

Method Detail

setStrategyMap

public void setStrategyMap(Map<String,VersionStrategy> map)

Set a Map with URL paths as keys and VersionStrategy as values.

Supports direct URL matches and Ant-style pattern matches. For syntax details, see the AntPathMatcher javadoc.

Parameters:

map - a map with URLs as keys and version strategies as values

getStrategyMap

public Map<String,VersionStrategy> getStrategyMap()

Return the map with version strategies keyed by path pattern.

addContentVersionStrategy

public VersionResourceResolver addContentVersionStrategy(String... pathPatterns)

Insert a content-based version in resource URLs that match the given path patterns. The version is computed from the content of the file, e.g. "css/main-e36d2e05253c6c7085a91522ce43a0b4.css". This is a good default strategy to use except when it cannot be, for example when using JavaScript module loaders, use addFixedVersionStrategy(java.lang.String, java.lang.String...) instead for serving JavaScript files.

Parameters:

pathPatterns - one or more resource URL path patterns, relative to the pattern configured with the resource handler

Returns:

the current instance for chained method invocation

See Also:

ContentVersionStrategy

addFixedVersionStrategy

public VersionResourceResolver addFixedVersionStrategy(String version,
                                                       String... pathPatterns)

Insert a fixed, prefix-based version in resource URLs that match the given path patterns, for example: "{version}/js/main.js". This is useful (vs. content-based versions) when using JavaScript module loaders.

The version may be a random number, the current date, or a value fetched from a git commit sha, a property file, or environment variable and set with SpEL expressions in the configuration (e.g. see @Value in Java config).

If not done already, variants of the given pathPatterns, prefixed with the version will be also configured. For example, adding a "/js/**" path pattern will also configure automatically a "/v1.0.0/js/**" with "v1.0.0" the version String given as an argument.

Parameters:

version - a version string

pathPatterns - one or more resource URL path patterns, relative to the pattern configured with the resource handler

Returns:

the current instance for chained method invocation

See Also:

FixedVersionStrategy

addVersionStrategy

public VersionResourceResolver addVersionStrategy(VersionStrategy strategy,
                                                  String... pathPatterns)

Register a custom VersionStrategy to apply to resource URLs that match the given path patterns.

Parameters:

strategy - the custom strategy

pathPatterns - one or more resource URL path patterns, relative to the pattern configured with the resource handler

Returns:

the current instance for chained method invocation

See Also:

VersionStrategy

resolveResourceInternal

protected Resource resolveResourceInternal(@Nullable
                                           HttpServletRequest request,
                                           String requestPath,
                                           List<? extends Resource> locations,
                                           ResourceResolverChain chain)

Specified by:

resolveResourceInternal in class AbstractResourceResolver

resolveUrlPathInternal

protected String resolveUrlPathInternal(String resourceUrlPath,
                                        List<? extends Resource> locations,
                                        ResourceResolverChain chain)

Specified by:

resolveUrlPathInternal in class AbstractResourceResolver

getStrategyForPath

@Nullable
protected VersionStrategy getStrategyForPath(String requestPath)

Find a VersionStrategy for the request path of the requested resource.

Returns:

an instance of a VersionStrategy or null if none matches that request path