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 com.nitesh.netty.snoop.server; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.codec.http.DefaultFullHttpResponse; import io.netty.handler.codec.http.FullHttpResponse; import io.netty.handler.codec.http.HttpContent; import io.netty.handler.codec.http.HttpHeaders; import io.netty.handler.codec.http.HttpRequest; import io.netty.handler.codec.http.LastHttpContent; import io.netty.util.CharsetUtil; import static io.netty.handler.codec.http.HttpHeaders.Names.CONNECTION; import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_LENGTH; import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_TYPE; import static io.netty.handler.codec.http.HttpHeaders.getHost; import static io.netty.handler.codec.http.HttpHeaders.is100ContinueExpected; import static io.netty.handler.codec.http.HttpHeaders.isKeepAlive; import static io.netty.handler.codec.http.HttpResponseStatus.CONTINUE; import static io.netty.handler.codec.http.HttpResponseStatus.OK; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; public class HttpSnoopServerHandler extends SimpleChannelInboundHandler<Object> { private HttpRequest request; /** Buffer that stores the response content */ private final StringBuilder buf = new StringBuilder(); @Override public void channelReadComplete(ChannelHandlerContext ctx) throws Exception { ctx.flush(); } @Override protected void channelRead0(ChannelHandlerContext ctx, Object msg) { if (msg instanceof HttpRequest) { HttpRequest request = this.request = (HttpRequest) msg; if (is100ContinueExpected(request)) { send100Continue(ctx); } buf.setLength(0); buf.append("Hi\r\n"); } if (msg instanceof HttpContent) { if (msg instanceof LastHttpContent) { writeResponse(ctx); } } } private boolean writeResponse(ChannelHandlerContext ctx) { // Decide whether to close the connection or not. boolean keepAlive = isKeepAlive(request); // Build the response object. FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, Unpooled.copiedBuffer(buf.toString(), CharsetUtil.UTF_8)); response.headers().set(CONTENT_TYPE, "text/plain; charset=UTF-8"); if (keepAlive) { // Add 'Content-Length' header only for a keep-alive connection. response.headers().set(CONTENT_LENGTH, response.content().readableBytes()); // Add keep alive header as per: // - http://www.w3.org/Protocols/HTTP/1.1/draft-ietf-http-v11-spec-01.html#Connection response.headers().set(CONNECTION, HttpHeaders.Values.KEEP_ALIVE); } // Write the response. ctx.write(response); return keepAlive; } private static void send100Continue(ChannelHandlerContext ctx) { FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, CONTINUE); ctx.write(response); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); ctx.close(); } }