/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.shindig.gadgets.render;
import org.apache.shindig.gadgets.Gadget;
import org.apache.shindig.gadgets.GadgetException;
import org.apache.shindig.gadgets.parse.GadgetHtmlParser;
import org.apache.shindig.gadgets.preload.PreloadedData;
import org.apache.shindig.gadgets.preload.PreloaderService;
import org.apache.shindig.gadgets.rewrite.GadgetRewriter;
import org.apache.shindig.gadgets.rewrite.MutableContent;
import org.apache.shindig.gadgets.rewrite.RewritingException;
import org.apache.shindig.gadgets.spec.View;
import java.util.Collection;
import java.util.List;
import com.google.inject.Inject;
/**
* Handles producing output markup for a gadget based on the provided context.
*/
public class HtmlRenderer {
public static final String PATH_PARAM = "path";
private final PreloaderService preloader;
private final ProxyRenderer proxyRenderer;
private final List<GadgetRewriter> gadgetRewriters;
private final GadgetHtmlParser htmlParser;
/**
* @param requestPipeline Used for performing the proxy request. Always ignores caching because
* we want to skip preloading when the object is in the cache.
* @param httpCache The shared http cache. Used before checking the request pipeline to determine
* whether to perform the preload / fetch cycle.
*/
@Inject
public HtmlRenderer(PreloaderService preloader,
ProxyRenderer proxyRenderer,
List<GadgetRewriter> gadgetRewriters,
GadgetHtmlParser htmlParser) {
this.preloader = preloader;
this.proxyRenderer = proxyRenderer;
this.gadgetRewriters = gadgetRewriters;
this.htmlParser = htmlParser;
}
/**
* Render the gadget into a string by performing the following steps:
*
* - Retrieve gadget specification information (GadgetSpec, MessageBundle, etc.)
*
* - Fetch any preloaded data needed to handle the request, as handled by Preloader.
*
* - Perform rewriting operations on the output content, handled by Rewriter.
*
* @param gadget The gadget for the rendering operation.
* @return The rendered gadget content
* @throws RenderingException if any issues arise that prevent rendering.
*/
public String render(Gadget gadget) throws RenderingException {
try {
View view = gadget.getCurrentView();
// We always execute these preloads, they have nothing to do with the cache output.
Collection<PreloadedData> preloads = preloader.preload(gadget);
gadget.setPreloads(preloads);
String content;
if (view.getHref() == null) {
content = view.getContent();
} else {
content = proxyRenderer.render(gadget);
}
MutableContent mc = new MutableContent(htmlParser, content);
for (GadgetRewriter rewriter : gadgetRewriters) {
rewriter.rewrite(gadget, mc);
}
return mc.getContent();
} catch (GadgetException e) {
throw new RenderingException(e.getMessage(), e);
} catch (RewritingException e) {
throw new RenderingException(e.getMessage(), e);
}
}
}