Java tutorial
/* * Copyright 2014 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 io.netty.handler.proxy; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelPipeline; import io.netty.handler.codec.base64.Base64; import io.netty.handler.codec.http.DefaultFullHttpRequest; import io.netty.handler.codec.http.FullHttpRequest; import io.netty.handler.codec.http.HttpClientCodec; import io.netty.handler.codec.http.HttpHeaderNames; import io.netty.handler.codec.http.HttpHeaders; import io.netty.handler.codec.http.HttpMethod; import io.netty.handler.codec.http.HttpResponse; import io.netty.handler.codec.http.HttpResponseStatus; import io.netty.handler.codec.http.HttpUtil; import io.netty.handler.codec.http.HttpVersion; import io.netty.handler.codec.http.LastHttpContent; import io.netty.util.AsciiString; import io.netty.util.CharsetUtil; import io.netty.util.internal.ObjectUtil; import java.net.InetSocketAddress; import java.net.SocketAddress; public final class HttpProxyHandler extends ProxyHandler { private static final String PROTOCOL = "http"; private static final String AUTH_BASIC = "basic"; private final HttpClientCodec codec = new HttpClientCodec(); private final String username; private final String password; private final CharSequence authorization; private final HttpHeaders outboundHeaders; private final boolean ignoreDefaultPortsInConnectHostHeader; private HttpResponseStatus status; private HttpHeaders inboundHeaders; public HttpProxyHandler(SocketAddress proxyAddress) { this(proxyAddress, null); } public HttpProxyHandler(SocketAddress proxyAddress, HttpHeaders headers) { this(proxyAddress, headers, false); } public HttpProxyHandler(SocketAddress proxyAddress, HttpHeaders headers, boolean ignoreDefaultPortsInConnectHostHeader) { super(proxyAddress); username = null; password = null; authorization = null; this.outboundHeaders = headers; this.ignoreDefaultPortsInConnectHostHeader = ignoreDefaultPortsInConnectHostHeader; } public HttpProxyHandler(SocketAddress proxyAddress, String username, String password) { this(proxyAddress, username, password, null); } public HttpProxyHandler(SocketAddress proxyAddress, String username, String password, HttpHeaders headers) { this(proxyAddress, username, password, headers, false); } public HttpProxyHandler(SocketAddress proxyAddress, String username, String password, HttpHeaders headers, boolean ignoreDefaultPortsInConnectHostHeader) { super(proxyAddress); this.username = ObjectUtil.checkNotNull(username, "username"); this.password = ObjectUtil.checkNotNull(password, "password"); ByteBuf authz = Unpooled.copiedBuffer(username + ':' + password, CharsetUtil.UTF_8); ByteBuf authzBase64 = Base64.encode(authz, false); authorization = new AsciiString("Basic " + authzBase64.toString(CharsetUtil.US_ASCII)); authz.release(); authzBase64.release(); this.outboundHeaders = headers; this.ignoreDefaultPortsInConnectHostHeader = ignoreDefaultPortsInConnectHostHeader; } @Override public String protocol() { return PROTOCOL; } @Override public String authScheme() { return authorization != null ? AUTH_BASIC : AUTH_NONE; } public String username() { return username; } public String password() { return password; } @Override protected void addCodec(ChannelHandlerContext ctx) throws Exception { ChannelPipeline p = ctx.pipeline(); String name = ctx.name(); p.addBefore(name, null, codec); } @Override protected void removeEncoder(ChannelHandlerContext ctx) throws Exception { codec.removeOutboundHandler(); } @Override protected void removeDecoder(ChannelHandlerContext ctx) throws Exception { codec.removeInboundHandler(); } @Override protected Object newInitialMessage(ChannelHandlerContext ctx) throws Exception { InetSocketAddress raddr = destinationAddress(); String hostString = HttpUtil.formatHostnameForHttp(raddr); int port = raddr.getPort(); String url = hostString + ":" + port; String hostHeader = (ignoreDefaultPortsInConnectHostHeader && (port == 80 || port == 443)) ? hostString : url; FullHttpRequest req = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.CONNECT, url, Unpooled.EMPTY_BUFFER, false); req.headers().set(HttpHeaderNames.HOST, hostHeader); if (authorization != null) { req.headers().set(HttpHeaderNames.PROXY_AUTHORIZATION, authorization); } if (outboundHeaders != null) { req.headers().add(outboundHeaders); } return req; } @Override protected boolean handleResponse(ChannelHandlerContext ctx, Object response) throws Exception { if (response instanceof HttpResponse) { if (status != null) { throw new HttpProxyConnectException(exceptionMessage("too many responses"), /*headers=*/ null); } HttpResponse res = (HttpResponse) response; status = res.status(); inboundHeaders = res.headers(); } boolean finished = response instanceof LastHttpContent; if (finished) { if (status == null) { throw new HttpProxyConnectException(exceptionMessage("missing response"), inboundHeaders); } if (status.code() != 200) { throw new HttpProxyConnectException(exceptionMessage("status: " + status), inboundHeaders); } } return finished; } /** * Specific case of a connection failure, which may include headers from the proxy. */ public static final class HttpProxyConnectException extends ProxyConnectException { private static final long serialVersionUID = -8824334609292146066L; private final HttpHeaders headers; /** * @param message The failure message. * @param headers Header associated with the connection failure. May be {@code null}. */ public HttpProxyConnectException(String message, HttpHeaders headers) { super(message); this.headers = headers; } /** * Returns headers, if any. May be {@code null}. */ public HttpHeaders headers() { return headers; } } }