com.eincs.decanter.handler.StaticFileHandler.java Source code

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Here is the source code for com.eincs.decanter.handler.StaticFileHandler.java

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/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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 com.eincs.decanter.handler;

import static org.jboss.netty.handler.codec.http.HttpHeaders.Names.CACHE_CONTROL;
import static org.jboss.netty.handler.codec.http.HttpHeaders.Names.CONTENT_LENGTH;
import static org.jboss.netty.handler.codec.http.HttpHeaders.Names.CONTENT_TYPE;
import static org.jboss.netty.handler.codec.http.HttpHeaders.Names.DATE;
import static org.jboss.netty.handler.codec.http.HttpHeaders.Names.EXPIRES;
import static org.jboss.netty.handler.codec.http.HttpHeaders.Names.IF_MODIFIED_SINCE;
import static org.jboss.netty.handler.codec.http.HttpHeaders.Names.LAST_MODIFIED;
import static org.jboss.netty.handler.codec.http.HttpMethod.GET;
import static org.jboss.netty.handler.codec.http.HttpResponseStatus.FORBIDDEN;
import static org.jboss.netty.handler.codec.http.HttpResponseStatus.METHOD_NOT_ALLOWED;
import static org.jboss.netty.handler.codec.http.HttpResponseStatus.NOT_FOUND;
import static org.jboss.netty.handler.codec.http.HttpResponseStatus.OK;
import static org.jboss.netty.handler.codec.http.HttpVersion.HTTP_1_1;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.Date;

import org.apache.commons.io.FilenameUtils;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.ChannelFutureProgressListener;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.DefaultFileRegion;
import org.jboss.netty.channel.FileRegion;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
import org.jboss.netty.handler.codec.http.DefaultHttpResponse;
import org.jboss.netty.handler.codec.http.HttpResponse;
import org.jboss.netty.handler.ssl.SslHandler;
import org.jboss.netty.handler.stream.ChunkedFile;

import com.eincs.decanter.handler.codec.http.HttpHeaderValues;
import com.eincs.decanter.message.DecanterChannels;
import com.eincs.decanter.message.DecanterContentType;
import com.eincs.decanter.message.DecanterRequest;

/**
 * A simple handler that serves incoming HTTP requests to send their respective
 * HTTP responses. It also implements {@code 'If-Modified-Since'} header to take
 * advantage of browser cache, as described in <a
 * href="http://tools.ietf.org/html/rfc2616#section-14.25">RFC 2616</a>.
 * 
 * <h3>How Browser Caching Works</h3>
 * 
 * Web browser caching works with HTTP headers as illustrated by the following
 * sample:
 * <ol>
 * <li>Request #1 returns the content of <code>/file1.txt</code>.</li>
 * <li>Contents of <code>/file1.txt</code> is cached by the browser.</li>
 * <li>Request #2 for <code>/file1.txt</code> does return the contents of the
 * file again. Rather, a 304 Not Modified is returned. This tells the browser to
 * use the contents stored in its cache.</li>
 * <li>The server knows the file has not been modified because the
 * <code>If-Modified-Since</code> date is the same as the file's last modified
 * date.</li>
 * </ol>
 * 
 * <pre>
 * Request #1 Headers
 * ===================
 * GET /file1.txt HTTP/1.1
 * 
 * Response #1 Headers
 * ===================
 * HTTP/1.1 200 OK
 * Date:               Tue, 01 Mar 2011 22:44:26 GMT
 * Last-Modified:      Wed, 30 Jun 2010 21:36:48 GMT
 * Expires:            Tue, 01 Mar 2012 22:44:26 GMT
 * Cache-Control:      private, max-age=31536000
 * 
 * Request #2 Headers
 * ===================
 * GET /file1.txt HTTP/1.1
 * If-Modified-Since:  Wed, 30 Jun 2010 21:36:48 GMT
 * 
 * Response #2 Headers
 * ===================
 * HTTP/1.1 304 Not Modified
 * Date:               Tue, 01 Mar 2011 22:44:28 GMT
 * 
 * </pre>
 */
public class StaticFileHandler extends SimpleChannelUpstreamHandler {

    public static final int HTTP_CACHE_SECONDS = 60;

    private final String path;
    private final File directory;

    /**
     * 
     * @param path
     * @param directory
     */
    public StaticFileHandler(String path, String directory) {
        this.path = path;
        this.directory = new File(directory);
        this.directory.mkdirs();
    }

    @Override
    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {

        if (!(e.getMessage() instanceof DecanterRequest)) {
            super.messageReceived(ctx, e);
            return;
        }

        final DecanterRequest request = (DecanterRequest) e.getMessage();
        final String path = request.getPath();
        if (!path.startsWith(this.path)) {
            super.messageReceived(ctx, e);
            return;
        }

        if (request.getMethod() != GET) {
            DecanterChannels.writeError(ctx, request, METHOD_NOT_ALLOWED);
            return;
        }

        final String subPath = path.substring(this.path.length());
        final String filePath = sanitizeUri(directory, subPath);
        if (filePath == null) {
            DecanterChannels.writeError(ctx, request, FORBIDDEN);
            return;
        }

        final File file = new File(filePath);
        if (file.isHidden() || !file.exists()) {
            DecanterChannels.writeError(ctx, request, NOT_FOUND);
            return;
        }

        if (!file.isFile()) {
            DecanterChannels.writeError(ctx, request, FORBIDDEN);
            return;
        }

        // Cache Validation
        String ifModifiedSince = request.getHeaders().get(IF_MODIFIED_SINCE);
        if (ifModifiedSince != null && ifModifiedSince.length() != 0) {
            Date ifModifiedSinceDate = HttpHeaderValues.parseDate(ifModifiedSince);

            // Only compare up to the second because the datetime format we send
            // to the client does
            // not have milliseconds
            long ifModifiedSinceDateSeconds = ifModifiedSinceDate.getTime() / 1000;
            long fileLastModifiedSeconds = file.lastModified() / 1000;
            if (ifModifiedSinceDateSeconds == fileLastModifiedSeconds) {
                DecanterChannels.writeNotModified(ctx, request);
                return;
            }
        }

        RandomAccessFile raf;
        try {
            raf = new RandomAccessFile(file, "r");
        } catch (FileNotFoundException fnfe) {
            DecanterChannels.writeError(ctx, request, NOT_FOUND);
            return;
        }
        long fileLength = raf.length();

        // Add cache headers
        long timeMillis = System.currentTimeMillis();
        long expireMillis = timeMillis + HTTP_CACHE_SECONDS * 1000;
        HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
        response.setHeader(CONTENT_TYPE, DecanterContentType.create(file));
        response.setHeader(CONTENT_LENGTH, String.valueOf(fileLength));
        response.setHeader(DATE, HttpHeaderValues.getCurrentDate());
        response.setHeader(EXPIRES, HttpHeaderValues.getDateString(expireMillis));
        response.setHeader(CACHE_CONTROL, "private, max-age=" + HTTP_CACHE_SECONDS);
        response.setHeader(LAST_MODIFIED, HttpHeaderValues.getDateString(file.lastModified()));

        Channel ch = e.getChannel();

        // Write the initial line and the header.
        ch.write(response);

        // Write the content.
        ChannelFuture writeFuture;
        if (ch.getPipeline().get(SslHandler.class) != null) {
            // Cannot use zero-copy with HTTPS.
            writeFuture = ch.write(new ChunkedFile(raf, 0, fileLength, 8192));
        } else {
            // No encryption - use zero-copy.
            final FileRegion region = new DefaultFileRegion(raf.getChannel(), 0, fileLength);
            writeFuture = ch.write(region);
            writeFuture.addListener(new ChannelFutureProgressListener() {
                public void operationComplete(ChannelFuture future) {
                    region.releaseExternalResources();
                }

                public void operationProgressed(ChannelFuture future, long amount, long current, long total) {
                    System.out.printf("%s: %d / %d (+%d)%n", filePath, current, total, amount);
                }
            });
        }
    }

    private static String sanitizeUri(File directory, String uri) {
        // Decode the path.
        try {
            uri = URLDecoder.decode(uri, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            try {
                uri = URLDecoder.decode(uri, "ISO-8859-1");
            } catch (UnsupportedEncodingException e1) {
                throw new Error();
            }
        }

        // Convert file separators.
        uri = uri.replace('/', File.separatorChar);

        // Simplistic dumb security check.
        // You will have to do something serious in the production environment.
        if (uri.contains(File.separator + '.') || uri.contains('.' + File.separator) || uri.startsWith(".")
                || uri.endsWith(".")) {
            return null;
        }

        // Convert to absolute path.
        String filePath = new File(directory, uri).getAbsolutePath();
        return FilenameUtils.normalize(filePath);
    }
}