PrecompressedArtifactFilter.java

/*
 * #%L
 * BroadleafCommerce Common Libraries
 * %%
 * Copyright (C) 2009 - 2016 Broadleaf Commerce
 * %%
 * Licensed under the Broadleaf Fair Use License Agreement, Version 1.0
 * (the "Fair Use License" located  at http://license.broadleafcommerce.org/fair_use_license-1.0.txt)
 * unless the restrictions on use therein are violated and require payment to Broadleaf in which case
 * the Broadleaf End User License Agreement (EULA), Version 1.1
 * (the "Commercial License" located at http://license.broadleafcommerce.org/commercial_license-1.1.txt)
 * shall apply.
 *
 * Alternatively, the Commercial License may be replaced with a mutually agreed upon license (the "Custom License")
 * between you and Broadleaf Commerce. You may not use this file except in compliance with the applicable license.
 * #L%
 */
package org.broadleafcommerce.common.web.util;

import org.apache.commons.lang.ArrayUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.core.env.Environment;
import org.springframework.web.filter.GenericFilterBean;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.MalformedURLException;
import java.util.Enumeration;
import java.util.List;

import javax.annotation.Resource;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author Jeff Fischer
 */
public class PrecompressedArtifactFilter extends GenericFilterBean {

    private boolean useWhileInDefaultEnvironment = true;

    @Autowired
    @Qualifier("blPrecompressedArtifactFileExtensionWhitelist")
    List<String> fileExtensionWhitelist;

    @Resource
    Environment environment;

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        checkOutput: {
            if (ArrayUtils.isNotEmpty(environment.getActiveProfiles()) || useWhileInDefaultEnvironment) {
                String path = getResourcePath(request);
                String gzipPath = path + ".gz";
                if (useGzipCompression(request, response, path, gzipPath)) {
                    File output = new File(getServletContext().getRealPath(gzipPath));
                    if (output.exists()) {
                        response.addHeader("Content-Encoding", "gzip");
                        ServletOutputStream sos = servletResponse.getOutputStream();
                        BufferedInputStream bis = null;
                        try {
                            bis = new BufferedInputStream(new FileInputStream(output));
                            boolean eof = false;
                            while (!eof) {
                                int temp = bis.read();
                                if (temp < 0) {
                                    eof = true;
                                } else {
                                    sos.write(temp);
                                }
                            }
                        } finally {
                            sos.flush();
                            try {
                                if (bis != null) {
                                    bis.close();
                                }
                            } catch (Exception e) {
                                //do nothing
                            }
                        }
                        break checkOutput;
                    }
                }
            }
            chain.doFilter(request, response);
        }
    }

    /**
     * Copied from Tomcat
     *
     * Return the page resource path from the request. For example:
     * <pre class="codeHtml">
     * <span class="blue">http://www.mycorp.com/banking/secure/login.htm</span>  ->  <span class="red">/secure/login.htm</span> </pre>
     *
     * @param request the page servlet request
     * @return the page resource path from the request
     */
    public String getResourcePath(HttpServletRequest request) {
        // Adapted from VelocityViewServlet.handleRequest() method:

        // If we get here from RequestDispatcher.include(), getServletPath()
        // will return the original (wrong) URI requested.  The following
        // special attribute holds the correct path.  See section 8.3 of the
        // Servlet 2.3 specification.

        String path = (String)
            request.getAttribute("javax.servlet.include.servlet_path");

        // Also take into account the PathInfo stated on
        // SRV.4.4 Request Path Elements.
        String info = (String)
            request.getAttribute("javax.servlet.include.path_info");

        if (path == null) {
            path = request.getServletPath();
            info = request.getPathInfo();
        }

        if (info != null) {
            path += info;
        }

        return path;
    }

    /**
     * Copied from Tomcat
     *
     * Return true if the response should be GZIP compressed.
     *
     * @param request the request to test
     * @param response the response to test
     * @param path the request path to test
     * @return true if the response should be GZIP compressed
     */
    protected boolean useGzipCompression(HttpServletRequest request, HttpServletResponse response, String path, String gzipPath) throws MalformedURLException {
        if (gzipPath == null) {
            return false;
        }

        String temp = path.toLowerCase();

        if (!fileExtensionInWhitelist(temp)) {
            return false;
        }

        if (getServletContext().getResource(gzipPath) == null) {
            return false;
        }

        // If Content-Encoding header is already set on response, skip compression
        if (response.containsHeader("Content-Encoding")) {
            return false;
        }

        // Are we allowed to compress ?
        String s = request.getParameter("gzip");
        if ("false".equals(s)) {
            return false;
        }

        Enumeration<?> e = request.getHeaders("Accept-Encoding");

        while (e.hasMoreElements()) {
            String name = (String) e.nextElement();
            if (name.contains("gzip")) {
                return true;
            }
        }

        return true;
    }

    protected boolean fileExtensionInWhitelist(String path) {
        if (path == null || !path.contains(".")) {
            return false;
        }

        path = path.toLowerCase();
        boolean inWhitelist = false;

        for (String validFileExtension : fileExtensionWhitelist) {
            if (path.endsWith(validFileExtension)) {
                inWhitelist = true;
                break;
            }
        }

        return inWhitelist;
    }

    public boolean isUseWhileInDefaultEnvironment() {
        return useWhileInDefaultEnvironment;
    }

    public void setUseWhileInDefaultEnvironment(boolean useWhileInDefaultEnvironment) {
        this.useWhileInDefaultEnvironment = useWhileInDefaultEnvironment;
    }

}