com.oculusinfo.tile.CacheConfigModule.java Source code

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Here is the source code for com.oculusinfo.tile.CacheConfigModule.java

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/*
 * Copyright (c) 2014 Oculus Info Inc.
 * http://www.oculusinfo.com/
 *
 * Released under the MIT License.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
    
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
    
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package com.oculusinfo.tile;

import com.google.common.io.Closeables;
import com.google.inject.Singleton;
import com.google.inject.servlet.ServletModule;
import com.oculusinfo.tile.util.ResourceHelper;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.constructs.blocking.LockTimeoutException;
import net.sf.ehcache.constructs.web.AlreadyCommittedException;
import net.sf.ehcache.constructs.web.AlreadyGzippedException;
import net.sf.ehcache.constructs.web.PageInfo;
import net.sf.ehcache.constructs.web.filter.FilterNonReentrantException;
import net.sf.ehcache.constructs.web.filter.SimplePageCachingFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.FilterChain;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;

/**
 * Set up caching
 *
 * @author rharper
 *
 */
public class CacheConfigModule extends ServletModule {

    /**
     * A trivial extension to the ehcache-web that ensures only GET method
     * requests are cached, all others are passed through.
     */
    @Singleton
    private static class CustomPageCachingFilter extends SimplePageCachingFilter {
        @Override
        protected void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
                throws AlreadyGzippedException, AlreadyCommittedException, FilterNonReentrantException,
                LockTimeoutException, Exception {

            if ("GET".equals(request.getMethod())) {
                // Go through cache
                if (response.isCommitted()) {
                    throw new AlreadyCommittedException("Response already committed before doing buildPage.");
                }
                logRequestHeaders(request);
                PageInfo pageInfo = buildPageInfo(request, response, chain);

                // Always write the response. This is necessary if
                // we want the ajax error handler to be able to
                // display exception messages from the server.
                writeResponse(request, response, pageInfo);
            } else {
                // Don't go through cache
                chain.doFilter(request, response);
            }
        }
    };

    final Logger logger = LoggerFactory.getLogger(getClass());

    private final ServletContext context;

    public CacheConfigModule(ServletContext context) {
        this.context = context;
    }

    @Override
    protected void configureServlets() {

        // Read the ehCache property from web.xml or override-web.xml
        String filename = context.getInitParameter("ehcacheConfig");

        try {
            logger.info("Loading ehcache configuration:");

            // Load properties
            InputStream inp = ResourceHelper.getStreamForPath(filename, "res:///ehcache.xml");

            // Create cache manager with provided configuration
            CacheManager.create(inp);

            Closeables.close(inp, false);

        } catch (IOException e) {
            // Failed to load properties, error
            addError(e);
        }

        // Filter all REST calls
        filter("/rest/*").through(CustomPageCachingFilter.class);

    }

}