Java tutorial
package cn.heroes.ud.protocol; /* * ==================================================================== * 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. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ import java.io.IOException; import java.io.InterruptedIOException; import java.net.ServerSocket; import java.net.Socket; import org.apache.http.ConnectionClosedException; import org.apache.http.ConnectionReuseStrategy; import org.apache.http.HttpClientConnection; import org.apache.http.HttpException; import org.apache.http.HttpHost; import org.apache.http.HttpRequest; import org.apache.http.HttpRequestInterceptor; import org.apache.http.HttpResponse; import org.apache.http.HttpResponseInterceptor; import org.apache.http.HttpServerConnection; import org.apache.http.impl.DefaultBHttpClientConnection; import org.apache.http.impl.DefaultBHttpServerConnection; import org.apache.http.impl.DefaultConnectionReuseStrategy; import org.apache.http.protocol.BasicHttpContext; import org.apache.http.protocol.HTTP; import org.apache.http.protocol.HttpContext; import org.apache.http.protocol.HttpCoreContext; import org.apache.http.protocol.HttpProcessor; import org.apache.http.protocol.HttpRequestExecutor; import org.apache.http.protocol.HttpRequestHandler; import org.apache.http.protocol.HttpService; import org.apache.http.protocol.ImmutableHttpProcessor; import org.apache.http.protocol.RequestConnControl; import org.apache.http.protocol.RequestContent; import org.apache.http.protocol.RequestExpectContinue; import org.apache.http.protocol.RequestTargetHost; import org.apache.http.protocol.RequestUserAgent; import org.apache.http.protocol.ResponseConnControl; import org.apache.http.protocol.ResponseContent; import org.apache.http.protocol.ResponseDate; import org.apache.http.protocol.ResponseServer; import org.apache.http.protocol.UriHttpRequestHandlerMapper; /** * Elemental HTTP/1.1 reverse proxy. */ public class ElementalReverseProxy { private static final String HTTP_IN_CONN = "http.proxy.in-conn"; private static final String HTTP_OUT_CONN = "http.proxy.out-conn"; private static final String HTTP_CONN_KEEPALIVE = "http.proxy.conn-keepalive"; public static void main(final String[] args) throws Exception { if (args.length < 1) { System.err.println("Please specified target hostname and port"); System.exit(1); } final String hostname = args[0]; int port = 80; if (args.length > 1) { port = Integer.parseInt(args[1]); } final HttpHost target = new HttpHost(hostname, port); final Thread t = new RequestListenerThread(8888, target); t.setDaemon(false); t.start(); } static class ProxyHandler implements HttpRequestHandler { private final HttpHost target; private final HttpProcessor httpproc; private final HttpRequestExecutor httpexecutor; private final ConnectionReuseStrategy connStrategy; public ProxyHandler(final HttpHost target, final HttpProcessor httpproc, final HttpRequestExecutor httpexecutor) { super(); this.target = target; this.httpproc = httpproc; this.httpexecutor = httpexecutor; this.connStrategy = DefaultConnectionReuseStrategy.INSTANCE; } public void handle(final HttpRequest request, final HttpResponse response, final HttpContext context) throws HttpException, IOException { final HttpClientConnection conn = (HttpClientConnection) context.getAttribute(HTTP_OUT_CONN); context.setAttribute(HttpCoreContext.HTTP_CONNECTION, conn); context.setAttribute(HttpCoreContext.HTTP_TARGET_HOST, this.target); System.out.println(">> Request URI: " + request.getRequestLine().getUri()); // Remove hop-by-hop headers request.removeHeaders(HTTP.CONTENT_LEN); request.removeHeaders(HTTP.TRANSFER_ENCODING); request.removeHeaders(HTTP.CONN_DIRECTIVE); request.removeHeaders("Keep-Alive"); request.removeHeaders("Proxy-Authenticate"); request.removeHeaders("TE"); request.removeHeaders("Trailers"); request.removeHeaders("Upgrade"); this.httpexecutor.preProcess(request, this.httpproc, context); final HttpResponse targetResponse = this.httpexecutor.execute(request, conn, context); this.httpexecutor.postProcess(response, this.httpproc, context); // Remove hop-by-hop headers targetResponse.removeHeaders(HTTP.CONTENT_LEN); targetResponse.removeHeaders(HTTP.TRANSFER_ENCODING); targetResponse.removeHeaders(HTTP.CONN_DIRECTIVE); targetResponse.removeHeaders("Keep-Alive"); targetResponse.removeHeaders("TE"); targetResponse.removeHeaders("Trailers"); targetResponse.removeHeaders("Upgrade"); response.setStatusLine(targetResponse.getStatusLine()); response.setHeaders(targetResponse.getAllHeaders()); response.setEntity(targetResponse.getEntity()); System.out.println("<< Response: " + response.getStatusLine()); final boolean keepalive = this.connStrategy.keepAlive(response, context); context.setAttribute(HTTP_CONN_KEEPALIVE, new Boolean(keepalive)); } } static class RequestListenerThread extends Thread { private final HttpHost target; private final ServerSocket serversocket; private final HttpService httpService; public RequestListenerThread(final int port, final HttpHost target) throws IOException { this.target = target; this.serversocket = new ServerSocket(port); // Set up HTTP protocol processor for incoming connections final HttpProcessor inhttpproc = new ImmutableHttpProcessor(new HttpRequestInterceptor[] { new RequestContent(), new RequestTargetHost(), new RequestConnControl(), new RequestUserAgent("Test/1.1"), new RequestExpectContinue(true) }); // Set up HTTP protocol processor for outgoing connections final HttpProcessor outhttpproc = new ImmutableHttpProcessor( new HttpResponseInterceptor[] { new ResponseDate(), new ResponseServer("Test/1.1"), new ResponseContent(), new ResponseConnControl() }); // Set up outgoing request executor final HttpRequestExecutor httpexecutor = new HttpRequestExecutor(); // Set up incoming request handler final UriHttpRequestHandlerMapper reqistry = new UriHttpRequestHandlerMapper(); reqistry.register("*", new ProxyHandler(this.target, outhttpproc, httpexecutor)); // Set up the HTTP service this.httpService = new HttpService(inhttpproc, reqistry); } @Override public void run() { System.out.println("Listening on port " + this.serversocket.getLocalPort()); while (!Thread.interrupted()) { try { final int bufsize = 8 * 1024; // Set up incoming HTTP connection final Socket insocket = this.serversocket.accept(); final DefaultBHttpServerConnection inconn = new DefaultBHttpServerConnection(bufsize); System.out.println("Incoming connection from " + insocket.getInetAddress()); inconn.bind(insocket); // Set up outgoing HTTP connection final Socket outsocket = new Socket(this.target.getHostName(), this.target.getPort()); final DefaultBHttpClientConnection outconn = new DefaultBHttpClientConnection(bufsize); outconn.bind(outsocket); System.out.println("Outgoing connection to " + outsocket.getInetAddress()); // Start worker thread final Thread t = new ProxyThread(this.httpService, inconn, outconn); t.setDaemon(true); t.start(); } catch (final InterruptedIOException ex) { break; } catch (final IOException e) { System.err.println("I/O error initialising connection thread: " + e.getMessage()); break; } } } } static class ProxyThread extends Thread { private final HttpService httpservice; private final HttpServerConnection inconn; private final HttpClientConnection outconn; public ProxyThread(final HttpService httpservice, final HttpServerConnection inconn, final HttpClientConnection outconn) { super(); this.httpservice = httpservice; this.inconn = inconn; this.outconn = outconn; } @Override public void run() { System.out.println("New connection thread"); final HttpContext context = new BasicHttpContext(null); // Bind connection objects to the execution context context.setAttribute(HTTP_IN_CONN, this.inconn); context.setAttribute(HTTP_OUT_CONN, this.outconn); try { while (!Thread.interrupted()) { if (!this.inconn.isOpen()) { this.outconn.close(); break; } this.httpservice.handleRequest(this.inconn, context); final Boolean keepalive = (Boolean) context.getAttribute(HTTP_CONN_KEEPALIVE); if (!Boolean.TRUE.equals(keepalive)) { this.outconn.close(); this.inconn.close(); break; } } } catch (final ConnectionClosedException ex) { System.err.println("Client closed connection"); } catch (final IOException ex) { System.err.println("I/O error: " + ex.getMessage()); } catch (final HttpException ex) { System.err.println("Unrecoverable HTTP protocol violation: " + ex.getMessage()); } finally { try { this.inconn.shutdown(); } catch (final IOException ignore) { } try { this.outconn.shutdown(); } catch (final IOException ignore) { } } } } }