GzipResourceResolver has NullPointerException when used with VersionResourceResolver [SPR-13149]

[spring-projects-issues]

Rakesh opened SPR-13149 and commented

Hi,

I have my Resource Handling config as below

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {

        //Set cachePeriod to 1 year if its not local mode
        Integer cachePeriod = (365*24*60*60);

        VersionResourceResolver versionResolver = new VersionResourceResolver()
                .addContentVersionStrategy("/**");

        registry.addResourceHandler("/**")
                .addResourceLocations("/")
                    .setCachePeriod(cachePeriod)
                        .resourceChain(true)
                            .addResolver(versionResolver)
                                .addResolver(new GzipResourceResolver())
                                .addResolver(new PathResourceResolver())
                                .addTransformer(new AppCacheManifestTransformer())
                                .addTransformer(new CssLinkResourceTransformer());
    }

My thymeleaf based HTML page has the resource as below

<link rel="stylesheet" th:href="@{/resources/css/bundle.min.css}"/>

Now, when this page is loading, the request fails with NullPointerException. Below is the stack trace

Caused by: org.thymeleaf.exceptions.TemplateProcessingException: Error during execution of processor 'org.thymeleaf.spring4.processor.attr.SpringHrefAttrProcessor' (error)
	at org.thymeleaf.processor.AbstractProcessor.process(AbstractProcessor.java:225) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.Node.applyNextProcessor(Node.java:1017) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.Node.processNode(Node.java:972) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.Node.processNode(Node.java:990) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.Node.processNode(Node.java:990) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.Node.processNode(Node.java:990) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.dom.Document.process(Document.java:93) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1155) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1060) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1011) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.spring4.view.ThymeleafView.renderFragment(ThymeleafView.java:335) [thymeleaf-spring4-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.spring4.view.ThymeleafView.render(ThymeleafView.java:190) [thymeleaf-spring4-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1244) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1027) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:971) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	... 140 more
Caused by: java.lang.NullPointerException
	at org.springframework.web.servlet.resource.GzipResourceResolver.isGzipAccepted(GzipResourceResolver.java:69) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.GzipResourceResolver.resolveResourceInternal(GzipResourceResolver.java:51) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.AbstractResourceResolver.resolveResource(AbstractResourceResolver.java:46) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.DefaultResourceResolverChain.resolveResource(DefaultResourceResolverChain.java:57) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.VersionResourceResolver.resolveUrlPathInternal(VersionResourceResolver.java:190) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.AbstractResourceResolver.resolveUrlPath(AbstractResourceResolver.java:60) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.DefaultResourceResolverChain.resolveUrlPath(DefaultResourceResolverChain.java:71) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.CachingResourceResolver.resolveUrlPathInternal(CachingResourceResolver.java:99) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.AbstractResourceResolver.resolveUrlPath(AbstractResourceResolver.java:60) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.DefaultResourceResolverChain.resolveUrlPath(DefaultResourceResolverChain.java:71) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.ResourceUrlProvider.getForLookupPath(ResourceUrlProvider.java:221) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.springframework.web.servlet.resource.ResourceUrlEncodingFilter$ResourceUrlEncodingResponseWrapper.encodeURL(ResourceUrlEncodingFilter.java:78) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
	at org.thymeleaf.standard.expression.LinkExpression.executeLink(LinkExpression.java:378) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.standard.expression.SimpleExpression.executeSimple(SimpleExpression.java:77) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.standard.expression.Expression.execute(Expression.java:103) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.standard.expression.Expression.execute(Expression.java:133) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.standard.expression.Expression.execute(Expression.java:120) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.standard.processor.attr.AbstractStandardSingleAttributeModifierAttrProcessor.getTargetAttributeValue(AbstractStandardSingleAttributeModifierAttrProcessor.java:67) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.spring4.processor.attr.SpringHrefAttrProcessor.getTargetAttributeValue(SpringHrefAttrProcessor.java:68) [thymeleaf-spring4-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.processor.attr.AbstractSingleAttributeModifierAttrProcessor.getModifiedAttributeValues(AbstractSingleAttributeModifierAttrProcessor.java:59) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.processor.attr.AbstractAttributeModifierAttrProcessor.processAttribute(AbstractAttributeModifierAttrProcessor.java:62) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.processor.attr.AbstractAttrProcessor.doProcess(AbstractAttrProcessor.java:87) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.thymeleaf.processor.AbstractProcessor.process(AbstractProcessor.java:212) [thymeleaf-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	... 162 more

This is because VersionResourceResolver passes the request object as null in below code snippet

@Override
protected String resolveUrlPathInternal(String resourceUrlPath, List<? extends Resource> locations, ResourceResolverChain chain) {
	String baseUrl = chain.resolveUrlPath(resourceUrlPath, locations);
	if (StringUtils.hasText(baseUrl)) {
		VersionStrategy versionStrategy = getStrategyForPath(resourceUrlPath);
		if (versionStrategy == null) {
			return null;
		}
		if (logger.isTraceEnabled()) {
			logger.trace("Getting the original resource to determine version");
		}
		Resource resource = chain.resolveResource(null, baseUrl, locations);
		String version = versionStrategy.getResourceVersion(resource);
		if (logger.isTraceEnabled()) {
			logger.trace("Version=" + version);
		}
		return versionStrategy.addVersion(baseUrl, version);
	}
	return baseUrl;
}

---

Affects: 4.1.6

Referenced from: commits b3f0199, 9ada55d

[spring-projects-issues]

Brian Clozel commented

Thanks for this report Rakesh!
This is fixed for 4.2.RC2; I've also backported the fix for 4.1.7.