Java tutorial
/* * 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 fr.kissy.zergling_push.infrastructure; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.DefaultFileRegion; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.codec.http.DefaultFullHttpResponse; import io.netty.handler.codec.http.DefaultHttpResponse; import io.netty.handler.codec.http.FullHttpRequest; import io.netty.handler.codec.http.FullHttpResponse; import io.netty.handler.codec.http.HttpChunkedInput; import io.netty.handler.codec.http.HttpHeaderNames; import io.netty.handler.codec.http.HttpUtil; import io.netty.handler.codec.http.HttpHeaderValues; import io.netty.handler.codec.http.HttpResponse; import io.netty.handler.codec.http.HttpResponseStatus; import io.netty.handler.codec.http.LastHttpContent; import io.netty.handler.ssl.SslHandler; import io.netty.handler.stream.ChunkedFile; import io.netty.util.CharsetUtil; import javax.activation.MimetypesFileTypeMap; import java.io.File; import java.io.FileNotFoundException; import java.io.RandomAccessFile; import java.io.UnsupportedEncodingException; import java.net.URLDecoder; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; import java.util.Locale; import java.util.TimeZone; import static io.netty.handler.codec.http.HttpMethod.*; import static io.netty.handler.codec.http.HttpResponseStatus.*; import static io.netty.handler.codec.http.HttpVersion.*; /** * 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}.</li> * <li>Contents of {@code /file1.txt} is cached by the browser.</li> * <li>Request #2 for {@code /file1.txt} 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} 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 HttpStaticFileServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> { private static final String HTTP_DATE_FORMAT = "EEE, dd MMM yyyy HH:mm:ss zzz"; private static final String HTTP_DATE_GMT_TIMEZONE = "GMT"; @Override public void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception { if (!request.decoderResult().isSuccess()) { sendError(ctx, BAD_REQUEST); return; } if (request.method() != GET) { sendError(ctx, METHOD_NOT_ALLOWED); return; } final String uri = request.uri(); final String path = sanitizeUri(uri); File file = new File(path); if (file.isHidden() || !file.exists()) { sendError(ctx, NOT_FOUND); return; } if (!file.isFile()) { sendError(ctx, FORBIDDEN); return; } RandomAccessFile raf; try { raf = new RandomAccessFile(file, "r"); } catch (FileNotFoundException ignore) { sendError(ctx, NOT_FOUND); return; } long fileLength = raf.length(); HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK); HttpUtil.setContentLength(response, fileLength); setContentTypeHeader(response, file); setDateAndCacheHeaders(response, file); if (HttpUtil.isKeepAlive(request)) { response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE); } // Write the initial line and the header. ctx.write(response); // Write the content. ChannelFuture lastContentFuture; if (ctx.pipeline().get(SslHandler.class) == null) { ctx.write(new DefaultFileRegion(raf.getChannel(), 0, fileLength), ctx.newProgressivePromise()); lastContentFuture = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT); } else { lastContentFuture = ctx.writeAndFlush(new HttpChunkedInput(new ChunkedFile(raf, 0, fileLength, 8192)), ctx.newProgressivePromise()); } // Decide whether to close the connection or not. if (!HttpUtil.isKeepAlive(request)) { // Close the connection when the whole content is written out. lastContentFuture.addListener(ChannelFutureListener.CLOSE); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { cause.printStackTrace(); if (ctx.channel().isActive()) { sendError(ctx, INTERNAL_SERVER_ERROR); } } private static String sanitizeUri(String uri) { // Decode the path. try { uri = URLDecoder.decode(uri, "UTF-8"); } catch (UnsupportedEncodingException e) { throw new Error(e); } if (uri.isEmpty() || uri.charAt(0) != '/' || uri.equals("/")) { uri = "/index.html"; } uri = uri.replace('/', File.separatorChar); return "src" + File.separator + "main" + File.separator + "webapp" + uri; } private static void sendError(ChannelHandlerContext ctx, HttpResponseStatus status) { FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, status, Unpooled.copiedBuffer("Failure: " + status + "\r\n", CharsetUtil.UTF_8)); response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain; charset=UTF-8"); // Close the connection as soon as the error message is sent. ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE); } /** * Sets the Date and Cache headers for the HTTP Response * * @param response * HTTP response * @param fileToCache * file to extract content type */ private static void setDateAndCacheHeaders(HttpResponse response, File fileToCache) { SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US); dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE)); // Date header Calendar time = new GregorianCalendar(); response.headers().set(HttpHeaderNames.DATE, dateFormatter.format(time.getTime())); // Add cache headers response.headers().set(HttpHeaderNames.EXPIRES, dateFormatter.format(time.getTime())); response.headers().set(HttpHeaderNames.CACHE_CONTROL, "no-store"); response.headers().set(HttpHeaderNames.LAST_MODIFIED, dateFormatter.format(new Date(fileToCache.lastModified()))); } /** * Sets the content type header for the HTTP Response * * @param response * HTTP response * @param file * file to extract content type */ private static void setContentTypeHeader(HttpResponse response, File file) { MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap(); response.headers().set(HttpHeaderNames.CONTENT_TYPE, mimeTypesMap.getContentType(file.getPath())); } }