/*
* This file is part of the Spider Web Framework.
*
* The Spider Web Framework is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* The Spider Web Framework is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the Spider Web Framework. If not, see <http://www.gnu.org/licenses/>.
*/
package com.medallia.spider.sttools;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import org.antlr.stringtemplate.StringTemplate;
import com.medallia.spider.StaticResources.StaticResource;
import com.medallia.spider.StaticResources.StaticResourceLookup;
import com.medallia.tiny.Encoding;
import com.medallia.tiny.Implement;
/**
* Tool that is supposed to add a hash to a link to a static resource
* to handle browser cache invalidation.
* <p>
*
* Note: not yet implemented, simply returns the link unmodified.
*
*/
public class CachedTool implements StTool {
private final StaticResourceLookup srl;
public CachedTool(StaticResourceLookup srl) {
this.srl = srl;
}
@Implement public String render(StringTemplate st) {
String resourceName = String.valueOf(st.getAttribute("it"));
StaticResource sr = srl.findStaticResource(resourceName);
if (sr != null) {
// copy into buffer and calculate md5
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
try {
sr.copyTo(buffer);
} catch (IOException e) {
throw new RuntimeException(e);
}
// create and return link
String md5 = Encoding.md5(buffer.toByteArray());
return resourceName + "?" + md5;
}
throw new RuntimeException("Resource not found: " + resourceName);
}
}