/*
* =============================================================================
*
* Copyright (c) 2011-2014, The THYMELEAF team (http://www.thymeleaf.org)
*
* 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.thymeleaf.spring3.view;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.js.ajax.AjaxHandler;
import org.springframework.util.StringUtils;
import org.thymeleaf.Configuration;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.dom.DOMSelector;
import org.thymeleaf.exceptions.ConfigurationException;
import org.thymeleaf.fragment.DOMSelectorFragmentSpec;
import org.thymeleaf.fragment.IFragmentSpec;
import org.thymeleaf.standard.fragment.StandardFragmentSignatureNodeReferenceChecker;
import org.thymeleaf.standard.processor.attr.StandardFragmentAttrProcessor;
/**
* <p>
* Subclass of {@link ThymeleafView} adding compatibility with AJAX events in
* Spring JavaScript (part of Spring WebFlow). This allows this View implementation
* to be able to return only <i>fragments</i> of the page.
* </p>
* <p>
* These rendering of fragments is used, for example, in Spring WebFlow's <render>
* instructions (though not only).
* </p>
* <p>
* This view searches for a comma-separated list of <i>fragment names</i> in a request
* parameter called <kbd>fragments</kbd>, and for each of them:
* </p>
* <ul>
* <li>If it is not a DOM selector, a <kbd>th:fragment</kdb> attribute will be used
* for designing the fragment to be rendered.</li>
* <li>If it is a DOM selector, it will be used for selecting the fragment to be rendered,
* without looking for any attributes. DOM Selectors are specified between brackets,
* like <kbd>[//div[@class='changeit']]</kbd></li>
* </ul>
*
* @author Daniel Fernández
*
* @since 2.0.11
*
*/
public class AjaxThymeleafView extends ThymeleafView implements AjaxEnabledView {
private static final Logger vlogger = LoggerFactory.getLogger(AjaxThymeleafView.class);
private static final String FRAGMENTS_PARAM = "fragments";
private AjaxHandler ajaxHandler = null;
public AjaxThymeleafView() {
super();
}
public AjaxHandler getAjaxHandler() {
return this.ajaxHandler;
}
public void setAjaxHandler(final AjaxHandler ajaxHandler) {
this.ajaxHandler = ajaxHandler;
}
@Override
public void render(
final Map<String, ?> model, final HttpServletRequest request, final HttpServletResponse response)
throws Exception {
final AjaxHandler templateAjaxHandler = getAjaxHandler();
if (templateAjaxHandler == null) {
throw new ConfigurationException("[THYMELEAF] AJAX Handler set into " +
AjaxThymeleafView.class.getSimpleName() + " instance for template " +
getTemplateName() + " is null.");
}
if (templateAjaxHandler.isAjaxRequest(request, response)) {
final String[] fragmentsToRender = getRenderFragments(model, request, response);
if (fragmentsToRender.length == 0) {
vlogger.warn("[THYMELEAF] An Ajax request was detected, but no fragments were specified to be re-rendered. "
+ "Falling back to full page render. This can cause unpredictable results when processing "
+ "the ajax response on the client.");
super.render(model, request, response);
return;
}
if (getTemplateEngine() == null) {
throw new IllegalArgumentException("Property 'templateEngine' is required");
}
final TemplateEngine templateEngine = getTemplateEngine();
final Configuration configuration = templateEngine.getConfiguration();
final String dialectPrefix = getStandardDialectPrefix(configuration);
final String fragmentSignatureAttributeName = StandardFragmentAttrProcessor.ATTR_NAME;
final DOMSelector.INodeReferenceChecker nodeReferenceChecker =
new StandardFragmentSignatureNodeReferenceChecker(configuration, dialectPrefix, fragmentSignatureAttributeName);
for (final String fragmentToRender : fragmentsToRender) {
if (fragmentToRender != null) {
String fragmentSelector = fragmentToRender;
if (fragmentSelector.length() > 3 &&
fragmentSelector.charAt(0) == '[' && fragmentSelector.charAt(fragmentSelector.length() - 1) == ']' &&
fragmentSelector.charAt(fragmentSelector.length() - 2) != '\'') {
// For legacy compatibility reasons, we allow fragment DOM Selector expressions to be specified
// between brackets. Just remove them.
fragmentSelector = fragmentSelector.substring(1, fragmentSelector.length() - 1);
}
final IFragmentSpec fragmentSpec = new DOMSelectorFragmentSpec(fragmentSelector, nodeReferenceChecker);
super.renderFragment(fragmentSpec, model, request, response);
}
}
} else {
super.render(model, request, response);
}
}
@SuppressWarnings({ "rawtypes", "unused" })
protected String[] getRenderFragments(
final Map model, final HttpServletRequest request, final HttpServletResponse response) {
final String fragmentsParam = request.getParameter(FRAGMENTS_PARAM);
final String[] renderFragments = StringUtils.commaDelimitedListToStringArray(fragmentsParam);
return StringUtils.trimArrayElements(renderFragments);
}
}