/*
* 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.olio.webapp.util;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
*
* @author Binu John
*
* Filter to add caching attributes to various files.
* By default, the filter is not enabled.
*/
public class CacheControlFilter implements Filter {
private FilterConfig config;
private Map<String, String> mimeMap = new HashMap<String, String>();
boolean isWildCardSpecified = false;
private boolean cacheEnabled = true; // Provide a System property based over ride mechanism
Logger logger = Logger.getLogger(CacheControlFilter.class.getName());
public void init(FilterConfig config) throws ServletException {
this.config = config;
// Populate the map.
configureCache();
if (!cacheEnabled) {
logger.info("static content caching is disabled");
return;
} else {
logger.info("static content caching is enabled");
}
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
if (cacheEnabled) {
HttpServletRequest hreq = (HttpServletRequest) request;
String path = hreq.getRequestURI();
String mimeType = config.getServletContext().getMimeType(path);
HttpServletResponse hres = (HttpServletResponse) response;
boolean found = false;
if (mimeType != null) {
if (isWildCardSpecified) {
int index = mimeType.indexOf("/");
if (index != -1) {
String mime = mimeType.substring(0, index + 1);
if (mimeMap.containsKey(mime)) {
hres.addHeader("Cache-Control", mimeMap.get(mime));
found = true;
}
}
}
if (!found && mimeMap.containsKey(mimeType)) {
hres.addHeader("Cache-Control", mimeMap.get(mimeType));
}
}
}
chain.doFilter(request, response);
}
public void destroy() {
}
private void configureCache() {
// Over ride defaults through a properties file
// 1. Check if the System property is set to disable it.
// 2. If caching is enabled, check the file specified by the System property first
// This is an over ride mechanism that allows the deployer to modify the behavior
// 3. Default behavior is taken from the Filter init params (web.xml)
cacheEnabled = !Boolean.getBoolean("disableStaticContentCaching");
if (!cacheEnabled) {
return;
}
// Overwrite the default if specified
String str = System.getProperty("staticContentCachingConfigurationFile");
if (str != null && new File(str).exists()) {
try {
InputStream is = new FileInputStream(str);
if (is != null) {
Properties props = new Properties();
props.load(is);
is.close();
// Parse the properties
Set<String> keys = props.stringPropertyNames();
Iterator<String> iter = keys.iterator();
while (iter.hasNext()) {
String key = iter.next();
processMimeType(key, props.getProperty(key));
}
return;
}
} catch (IOException ex) {
Logger.getLogger(CacheControlFilter.class.getName()).log(Level.SEVERE, null, ex);
}
} else {
Enumeration<String> emimes = config.getInitParameterNames();
while (emimes.hasMoreElements()) {
String mime = emimes.nextElement();
String value = config.getInitParameter(mime);
processMimeType(mime, value);
}
}
}
private void processMimeType(String mime, String value) {
if (value == null) {
return;
}
int index = mime.indexOf("/");
if (index == -1 || mime.length() < 3) // Incorrect mime specification
{
return;
}
// Check for wild cards
if (mime.charAt(mime.length() - 1) == '*') {
String wcard = mime.substring(0, index + 1);
mimeMap.put(wcard, value);
isWildCardSpecified = true;
} else {
mimeMap.put(mime, value);
}
}
}