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Thymeleaf implementation of Dandelion that provides a Thymeleaf dialect.
/*
* [The "BSD licence"]
* Copyright (c) 2013-2015 Dandelion
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Dandelion nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.github.dandelion.thymeleaf.web.handler.impl;
import java.io.UnsupportedEncodingException;
import java.util.Calendar;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.WebContext;
import com.github.dandelion.core.DandelionException;
import com.github.dandelion.core.asset.Asset;
import com.github.dandelion.core.cache.Cache;
import com.github.dandelion.core.util.AssetUtils;
import com.github.dandelion.core.util.StringUtils;
import com.github.dandelion.core.web.RequestFlashData;
import com.github.dandelion.core.web.handler.AbstractHandlerChain;
import com.github.dandelion.core.web.handler.HandlerContext;
import com.github.dandelion.core.web.handler.cache.HttpHeader;
import com.github.dandelion.core.web.handler.cache.HttpHeaderUtils;
import com.github.dandelion.thymeleaf.resourceresolver.JsResourceResolver;
import com.github.dandelion.thymeleaf.templatemode.DandelionTemplateModeHandlers;
import com.github.dandelion.thymeleaf.templateresolver.JsTemplateResolver;
/**
*
* Post-filtering request handler in charge of processing external Javascript
* assets with Thymeleaf expressions.
*
*
* Only applies on "user assets" (i.e. non vendor).
*
*
* @author Thibault Duchateau
* @since 1.0.0
*/
public class ProcessJsPostHandler extends AbstractHandlerChain {
private static final Logger LOG = LoggerFactory.getLogger(ProcessJsPostHandler.class);
/**
* Thymeleaf template engine.
*/
private static TemplateEngine templateEngine;
private static Set compatibleMimeTypes;
/**
* Initialisation of the template engine with the custom template mode.
*/
static {
JsTemplateResolver templateResolver = new JsTemplateResolver();
templateResolver.setTemplateMode(DandelionTemplateModeHandlers.TEMPLATEMODE_DANDELION_JS);
templateResolver.setCacheable(false);
templateEngine = new TemplateEngine();
templateEngine.addTemplateModeHandler(DandelionTemplateModeHandlers.DANDELION_JS);
templateEngine.setTemplateResolver(templateResolver);
compatibleMimeTypes = new HashSet();
compatibleMimeTypes.add("application/x-javascript");
compatibleMimeTypes.add("application/javascript");
compatibleMimeTypes.add("text/javascript");
compatibleMimeTypes.add("text/ecmascript");
compatibleMimeTypes.add("application/ecmascript");
compatibleMimeTypes.add("text/jscript");
}
@Override
protected Logger getLogger() {
return LOG;
}
@Override
public boolean isAfterChaining() {
return true;
}
@Override
public int getRank() {
return 2;
}
@Override
public boolean isApplicable(HandlerContext handlerContext) {
// Retrieves the content type from the filtered response and remove
// charset if present
String mimeType = handlerContext.getResponse().getContentType();
boolean compatibleMimeType = StringUtils.isNotBlank(mimeType) && compatibleMimeTypes.contains(mimeType.split(";")[0]);
String servletUrlPattern = handlerContext.getContext().getConfiguration().getAssetUrlPattern()
.replaceAll("/\\*", "");
boolean matchesServletName = handlerContext.getRequest().getRequestURL().toString().contains(servletUrlPattern);
LOG.trace("compatibleMimeType: {}, matchesServletName: {}", compatibleMimeType, matchesServletName);
boolean isJsProcessingEnabled = handlerContext.getContext().getConfiguration().isAssetJsProcessingEnabled();
return isJsProcessingEnabled && compatibleMimeType && matchesServletName;
}
@Override
public boolean handle(HandlerContext handlerContext) {
// Get the asset content thanks to the cache key
String cacheKey = AssetUtils.extractCacheKeyFromRequest(handlerContext.getRequest());
Asset asset = handlerContext.getContext().getAssetStorage().get(cacheKey).getAsset();
// Update the current context with additional attributes
WebContext ctx = new WebContext(handlerContext.getRequest(), handlerContext.getResponse(), handlerContext
.getRequest().getServletContext(), handlerContext.getRequest().getLocale());
// Retrieve the cached request attributes from cache
String requestKey = AssetUtils.extractRequestKeyFromRequest(handlerContext.getRequest());
RequestFlashData requestData = handlerContext.getContext().getRequestFlashDataCache().get(requestKey);
if (requestData != null) {
ctx.setVariables(requestData.getAttributes());
}
// Process the Javascript asset
String processed = templateEngine.process(asset.getName(), ctx);
// Housecleaning
processed = processed.replace(JsResourceResolver.BLOCK_WRAP_CDATA_START, "");
processed = processed.replace(JsResourceResolver.BLOCK_WRAP_CDATA_END, "");
String configuredEncoding = handlerContext.getContext().getConfiguration().getEncoding();
// Update HTTP headers so that this asset is never cached
handlerContext.getResponse().setHeader(HttpHeader.CACHE_CONTROL.getName(), "no-cache, no-store");
handlerContext.getResponse().setHeader(HttpHeader.ETAG.getName(),
HttpHeaderUtils.computeETag(handlerContext.getResponseAsBytes(), handlerContext));
Calendar past = Calendar.getInstance();
past.add(Calendar.YEAR, -1);
handlerContext.getResponse().setDateHeader(HttpHeader.EXPIRES.getName(), past.getTimeInMillis());
handlerContext.getResponse().setHeader(HttpHeader.VARY.getName(), "Accept-Encoding");
// Clean flash data cache
Cache cache = handlerContext.getContext().getRequestFlashDataCache();
Iterator iterator = cache.keySet().iterator();
while (iterator.hasNext()) {
String key = iterator.next();
if (cache.get(key).isExpired()) {
iterator.remove();
}
}
// Override the response with the processed Javascript
try {
handlerContext.setResponseAsBytes(processed.getBytes(configuredEncoding));
}
catch (UnsupportedEncodingException e) {
throw new DandelionException("Unable to encode the HTML page using the '" + configuredEncoding
+ "', which doesn't seem to be supported", e);
}
return false;
}
}