Tomcat example source code file (SSIFilter.java)

This example Tomcat source code file (SSIFilter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

bytearrayoutputstream, bytearrayoutputstream, bytearrayservletoutputstream, http, httpservletrequest, httpservletresponse, io, pattern, printwriter, printwriter, regex, request, response, servlet, servletexception, servletexception, ssifilter, ssiprocessor, string, string

The Tomcat SSIFilter.java source code

/*
 * 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.catalina.ssi;


import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Reader;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

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;

import org.apache.catalina.Globals;
/**
 * Filter to process SSI requests within a webpage. Mapped to a content types
 * from within web.xml.
 * 
 * @author David Becker
 * @version $Revision: 531303 $, $Date: 2007-04-23 02:24:01 +0200 (lun., 23 avr. 2007) $
 * @see org.apache.catalina.ssi.SSIServlet
 */
public class SSIFilter implements Filter {
	protected FilterConfig config = null;
    /** Debug level for this servlet. */
    protected int debug = 0;
    /** Expiration time in seconds for the doc. */
    protected Long expires = null;
    /** virtual path can be webapp-relative */
    protected boolean isVirtualWebappRelative = false;
    /** regex pattern to match when evaluating content types */
	protected Pattern contentTypeRegEx = null;
	/** default pattern for ssi filter content type matching */
	protected Pattern shtmlRegEx =
        Pattern.compile("text/x-server-parsed-html(;.*)?");


    //----------------- Public methods.
    /**
     * Initialize this servlet.
     * 
     * @exception ServletException
     *                if an error occurs
     */
    public void init(FilterConfig config) throws ServletException {
    	this.config = config;
    	
        if (config.getInitParameter("debug") != null) {
            debug = Integer.parseInt(config.getInitParameter("debug"));
        }

        if (config.getInitParameter("contentType") != null) {
            contentTypeRegEx = Pattern.compile(config.getInitParameter("contentType"));
        } else {
            contentTypeRegEx = shtmlRegEx;
        }

        isVirtualWebappRelative = 
            Boolean.parseBoolean(config.getInitParameter("isVirtualWebappRelative"));

        if (config.getInitParameter("expires") != null)
            expires = Long.valueOf(config.getInitParameter("expires"));

        if (debug > 0)
            config.getServletContext().log(
                    "SSIFilter.init() SSI invoker started with 'debug'=" + debug);
    }

    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        // cast once
        HttpServletRequest req = (HttpServletRequest)request;
        HttpServletResponse res = (HttpServletResponse)response;
        
        // indicate that we're in SSI processing
        req.setAttribute(Globals.SSI_FLAG_ATTR, "true");           

        // setup to capture output
        ByteArrayServletOutputStream basos = new ByteArrayServletOutputStream();
        ResponseIncludeWrapper responseIncludeWrapper =
            new ResponseIncludeWrapper(config.getServletContext(),req, res, basos);

        // process remainder of filter chain
        chain.doFilter(req, responseIncludeWrapper);

        // we can't assume the chain flushed its output
        responseIncludeWrapper.flushOutputStreamOrWriter();
        byte[] bytes = basos.toByteArray();

        // get content type
        String contentType = responseIncludeWrapper.getContentType();

        // is this an allowed type for SSI processing?
        if (contentTypeRegEx.matcher(contentType).matches()) {
            String encoding = res.getCharacterEncoding();

            // set up SSI processing 
            SSIExternalResolver ssiExternalResolver =
                new SSIServletExternalResolver(config.getServletContext(), req,
                        res, isVirtualWebappRelative, debug, encoding);
            SSIProcessor ssiProcessor = new SSIProcessor(ssiExternalResolver,
                    debug);
            
            // prepare readers/writers
            Reader reader =
                new InputStreamReader(new ByteArrayInputStream(bytes), encoding);
            ByteArrayOutputStream ssiout = new ByteArrayOutputStream();
            PrintWriter writer =
                new PrintWriter(new OutputStreamWriter(ssiout, encoding));
            
            // do SSI processing  
            long lastModified = ssiProcessor.process(reader,
                    responseIncludeWrapper.getLastModified(), writer);
            
            // set output bytes
            writer.flush();
            bytes = ssiout.toByteArray();
            
            // override headers
            if (expires != null) {
                res.setDateHeader("expires", (new java.util.Date()).getTime()
                        + expires.longValue() * 1000);
            }
            if (lastModified > 0) {
                res.setDateHeader("last-modified", lastModified);
            }
            res.setContentLength(bytes.length);
            
            Matcher shtmlMatcher =
                shtmlRegEx.matcher(responseIncludeWrapper.getContentType());
            if (shtmlMatcher.matches()) {
            	// Convert shtml mime type to ordinary html mime type but preserve
                // encoding, if any.
            	String enc = shtmlMatcher.group(1);
            	res.setContentType("text/html" + ((enc != null) ? enc : ""));
            }
        }

        // write output
        OutputStream out = null;
        try {
            out = res.getOutputStream();
        } catch (IllegalStateException e) {
            // Ignore, will try to use a writer
        }
        if (out == null) {
            res.getWriter().write(new String(bytes));
        } else {
            out.write(bytes);
        }
    }

    public void destroy() {
    }
}