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 org.camunda.bpm.debugger.server.netty.staticresource; import static io.netty.handler.codec.http.HttpHeaders.Names.CACHE_CONTROL; import static io.netty.handler.codec.http.HttpHeaders.Names.CONNECTION; import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_TYPE; import static io.netty.handler.codec.http.HttpHeaders.Names.DATE; import static io.netty.handler.codec.http.HttpHeaders.Names.EXPIRES; import static io.netty.handler.codec.http.HttpHeaders.Names.IF_MODIFIED_SINCE; import static io.netty.handler.codec.http.HttpHeaders.Names.LAST_MODIFIED; import static io.netty.handler.codec.http.HttpMethod.GET; import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST; import static io.netty.handler.codec.http.HttpResponseStatus.FORBIDDEN; import static io.netty.handler.codec.http.HttpResponseStatus.INTERNAL_SERVER_ERROR; import static io.netty.handler.codec.http.HttpResponseStatus.METHOD_NOT_ALLOWED; import static io.netty.handler.codec.http.HttpResponseStatus.NOT_FOUND; import static io.netty.handler.codec.http.HttpResponseStatus.NOT_MODIFIED; import static io.netty.handler.codec.http.HttpResponseStatus.OK; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; 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.HttpHeaders; 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.stream.ChunkedStream; import io.netty.util.CharsetUtil; import java.io.InputStream; import java.io.UnsupportedEncodingException; import java.lang.management.ManagementFactory; 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 javax.activation.MimetypesFileTypeMap; public class HttpClasspathServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> { public static final String HTTP_DATE_FORMAT = "EEE, dd MMM yyyy HH:mm:ss zzz"; public static final String HTTP_DATE_GMT_TIMEZONE = "GMT"; public static final int HTTP_CACHE_SECONDS = 60; @Override public void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception { if (!request.getDecoderResult().isSuccess()) { sendError(ctx, BAD_REQUEST); return; } if (request.getMethod() != GET) { sendError(ctx, METHOD_NOT_ALLOWED); return; } final String uri = request.getUri(); final String path = sanitizeUri(uri); if (path == null) { sendError(ctx, FORBIDDEN); return; } // Cache Validation String ifModifiedSince = request.headers().get(IF_MODIFIED_SINCE); if (ifModifiedSince != null && !ifModifiedSince.isEmpty()) { SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US); Date ifModifiedSinceDate = dateFormatter.parse(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; // we use the start time of the JVM as last modified date long lastModifiedSeconds = ManagementFactory.getRuntimeMXBean().getStartTime(); if (ifModifiedSinceDateSeconds == lastModifiedSeconds) { sendNotModified(ctx); return; } } ClassLoader classLoader = HttpClasspathServerHandler.class.getClassLoader(); InputStream stream = classLoader.getResourceAsStream(path); if (stream == null) { sendError(ctx, NOT_FOUND); return; } HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK); HttpHeaders.setContentLength(response, stream.available()); setContentTypeHeader(response, path); setDateAndCacheHeaders(response); if (HttpHeaders.isKeepAlive(request)) { response.headers().set(CONNECTION, HttpHeaders.Values.KEEP_ALIVE); } // Write the initial line and the header. ctx.write(response); // Write the content. ChannelFuture sendFileFuture = ctx.write(new ChunkedStream(stream), ctx.newProgressivePromise()); // Write the end marker. ChannelFuture lastContentFuture = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT); // Decide whether to close the connection or not. if (!HttpHeaders.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) != '/') { return null; } if (uri.equals("/")) { return "index.html"; } else { // remove leading '/' return uri.substring(1); } } 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(CONTENT_TYPE, "text/plain; charset=UTF-8"); // Close the connection as soon as the error message is sent. ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE); } /** * When file timestamp is the same as what the browser is sending up, send a "304 Not Modified" * * @param ctx * Context */ private static void sendNotModified(ChannelHandlerContext ctx) { FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, NOT_MODIFIED); setDateHeader(response); // Close the connection as soon as the error message is sent. ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE); } /** * Sets the Date header for the HTTP response * * @param response * HTTP response */ private static void setDateHeader(FullHttpResponse response) { SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US); dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE)); Calendar time = new GregorianCalendar(); response.headers().set(DATE, dateFormatter.format(time.getTime())); } /** * 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) { 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(DATE, dateFormatter.format(time.getTime())); // Add cache headers time.add(Calendar.SECOND, HTTP_CACHE_SECONDS); response.headers().set(EXPIRES, dateFormatter.format(time.getTime())); response.headers().set(CACHE_CONTROL, "private, max-age=" + HTTP_CACHE_SECONDS); response.headers().set(LAST_MODIFIED, dateFormatter.format(new Date(ManagementFactory.getRuntimeMXBean().getStartTime()))); } /** * 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, String path) { String contentType = null; if (path.endsWith(".css")) { contentType = "text/css"; } else if (path.endsWith(".js")) { contentType = "application/javascript"; } else if (path.endsWith(".html")) { contentType = "text/html"; } else { MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap(); contentType = mimeTypesMap.getContentType(path); } response.headers().set(CONTENT_TYPE, contentType); } }