/*
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.servlet.view.groovy;
import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import groovy.text.markup.MarkupTemplateEngine;
import groovy.text.markup.TemplateConfiguration;
import groovy.text.markup.TemplateResolver;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.i18n.LocaleContextHolder;
import org.springframework.core.io.Resource;
import org.springframework.util.StringUtils;
/**
* An extension of Groovy's {@link groovy.text.markup.TemplateConfiguration} and
* an implementation of Spring MVC's {@link GroovyMarkupConfig} for creating
* a {@code MarkupTemplateEngine} for use in a web application. The most basic
* way to configure this class is to set the "resourceLoaderPath". For example:
*
* <pre class="code">
*
* // Add the following to an @Configuration class
*
* @Bean
* public GroovyMarkupConfig groovyMarkupConfigurer() {
* GroovyMarkupConfigurer configurer = new GroovyMarkupConfigurer();
* configurer.setResourceLoaderPath("classpath:/WEB-INF/groovymarkup/");
* return configurer;
* }
* </pre>
*
* By default this bean will create a {@link MarkupTemplateEngine} with:
* <ul>
* <li>a parent ClassLoader for loading Groovy templates with their references
* <li>the default configuration in the base class {@link TemplateConfiguration}
* <li>a {@link groovy.text.markup.TemplateResolver} for resolving template files
* </ul>
*
* You can provide the {@link MarkupTemplateEngine} instance directly to this bean
* in which case all other properties will not be effectively ignored.
*
* <p>This bean must be included in the application context of any application
* using the Spring MVC {@link GroovyMarkupView} for rendering. It exists purely
* for the purpose of configuring Groovy's Markup templates. It is not meant to be
* referenced by application components directly. It implements GroovyMarkupConfig
* to be found by GroovyMarkupView without depending on a bean name. Each
* DispatcherServlet can define its own GroovyMarkupConfigurer if desired.
*
* <p>Note that resource caching is enabled by default in {@link MarkupTemplateEngine}.
* Use the {@link #setCacheTemplates(boolean)} to configure that as necessary.
* <p>Spring's Groovy Markup template support requires Groovy 2.3.1 or higher.
*
* @author Brian Clozel
* @author Rossen Stoyanchev
* @since 4.1
* @see GroovyMarkupView
* @see <a href="http://groovy-lang.org/templating.html#_the_markuptemplateengine">
* Groovy Markup Template engine documentation</a>
*/
public class GroovyMarkupConfigurer extends TemplateConfiguration
implements GroovyMarkupConfig, ApplicationContextAware, InitializingBean {
private String resourceLoaderPath = "classpath:";
private MarkupTemplateEngine templateEngine;
private ApplicationContext applicationContext;
/**
* Set the Groovy Markup Template resource loader path(s) via a Spring resource
* location. Accepts multiple locations as a comma-separated list of paths.
* Standard URLs like "file:" and "classpath:" and pseudo URLs are supported
* as understood by Spring's {@link org.springframework.core.io.ResourceLoader}.
* Relative paths are allowed when running in an ApplicationContext.
*
*/
public void setResourceLoaderPath(String resourceLoaderPath) {
this.resourceLoaderPath = resourceLoaderPath;
}
public String getResourceLoaderPath() {
return this.resourceLoaderPath;
}
/**
* Set a pre-configured MarkupTemplateEngine to use for the Groovy Markup
* Template web configuration.
* <p>Note that this engine instance has to be manually configured, since all
* other bean properties of this configurer will be ignored.
*/
public void setTemplateEngine(MarkupTemplateEngine templateEngine) {
this.templateEngine = templateEngine;
}
public MarkupTemplateEngine getTemplateEngine() {
return templateEngine;
}
@Override
public void setApplicationContext(ApplicationContext applicationContext) {
this.applicationContext = applicationContext;
}
protected ApplicationContext getApplicationContext() {
return this.applicationContext;
}
/**
* This method should not be used, since the considered Locale for resolving
* templates is the Locale for the current HTTP request.
*/
@Override
public void setLocale(Locale locale) {
super.setLocale(locale);
}
@Override
public void afterPropertiesSet() throws Exception {
if (this.templateEngine == null) {
this.templateEngine = createTemplateEngine();
}
}
protected MarkupTemplateEngine createTemplateEngine() throws IOException {
if (this.templateEngine == null) {
ClassLoader templateClassLoader = createTemplateClassLoader();
this.templateEngine = new MarkupTemplateEngine(templateClassLoader, this, new LocaleTemplateResolver());
}
return this.templateEngine;
}
/**
* Create a parent ClassLoader for Groovy to use as parent ClassLoader
* when loading and compiling templates.
*/
protected ClassLoader createTemplateClassLoader() throws IOException {
String[] paths = StringUtils.commaDelimitedListToStringArray(getResourceLoaderPath());
List<URL> urls = new ArrayList<>();
for (String path : paths) {
Resource[] resources = getApplicationContext().getResources(path);
if (resources.length > 0) {
for (Resource resource : resources) {
if (resource.exists()) {
urls.add(resource.getURL());
}
}
}
}
ClassLoader classLoader = getApplicationContext().getClassLoader();
return (urls.size() > 0 ? new URLClassLoader(urls.toArray(new URL[urls.size()]), classLoader) : classLoader);
}
/**
* Resolve a template from the given template path.
* <p>The default implementation uses the Locale associated with the current request,
* as obtained through {@link org.springframework.context.i18n.LocaleContextHolder LocaleContextHolder},
* to find the template file. Effectively the locale configured at the engine level is ignored.
* @see LocaleContextHolder
* @see #setLocale
*/
protected URL resolveTemplate(ClassLoader classLoader, String templatePath) throws IOException {
MarkupTemplateEngine.TemplateResource resource = MarkupTemplateEngine.TemplateResource.parse(templatePath);
Locale locale = LocaleContextHolder.getLocale();
URL url = classLoader.getResource(resource.withLocale(locale.toString().replace("-", "_")).toString());
if (url == null) {
url = classLoader.getResource(resource.withLocale(locale.getLanguage()).toString());
}
if (url == null) {
url = classLoader.getResource(resource.withLocale(null).toString());
}
if (url == null) {
throw new IOException("Unable to load template:" + templatePath);
}
return url;
}
/**
* Custom {@link TemplateResolver template resolver} that simply delegates to
* {@link #resolveTemplate(ClassLoader, String)}..
*/
private class LocaleTemplateResolver implements TemplateResolver {
private ClassLoader classLoader;
@Override
public void configure(ClassLoader templateClassLoader, TemplateConfiguration configuration) {
this.classLoader = templateClassLoader;
}
@Override
public URL resolveTemplate(String templatePath) throws IOException {
return GroovyMarkupConfigurer.this.resolveTemplate(this.classLoader, templatePath);
}
}
}