目录
HTTP/HTTPS Proxy Server
直接上代码：HttpProxyServer
import io.netty.bootstrap.Bootstrap; import io.netty.bootstrap.ServerBootstrap; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.*; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.SocketChannel; import io.netty.channel.socket.nio.NioServerSocketChannel; import io.netty.handler.logging.LogLevel; import io.netty.handler.logging.LoggingHandler; /** * HTTP/HTTPS代理服务器 * 三个角色：真实客户端，代理客户端，目标主机 * * 数据流向： * * ------->> 代理客户端--------->> * 真实客户端 目标主机 * <<-------- 代理客户端<<-------- * */ public class HttpProxyServer { int port; public HttpProxyServer(int port) { this.port = port; } public static void main(String[] args) throws Exception { new HttpProxyServer(8443).run(); } public void run() throws Exception { EventLoopGroup bossGroup = new NioEventLoopGroup(1); EventLoopGroup workerGroup = new NioEventLoopGroup(); try { ServerBootstrap b = new ServerBootstrap(); b.group(bossGroup, workerGroup) .channel(NioServerSocketChannel.class) .handler(new LoggingHandler(LogLevel.INFO)) .childHandler(new ChannelInitializer<SocketChannel>() { @Override public void initChannel(SocketChannel ch) throws Exception { ch.pipeline().addLast( new LoggingHandler(LogLevel.DEBUG), new HttpProxyClientHandler()); } }) .bind(port).sync().channel().closeFuture().sync(); } catch (InterruptedException e) { e.printStackTrace(); } finally { bossGroup.shutdownGracefully(); workerGroup.shutdownGracefully(); } } /** * 代理客户端去请求目标主机 */ private static class HttpProxyClientHandler extends ChannelInboundHandlerAdapter { /*代理服务端channel*/ private Channel clientChannel; /*目标主机channel*/ private Channel remoteChannel; /*解析真实客户端的header*/ private HttpProxyClientHeader header = new HttpProxyClientHeader(); @Override public void channelActive(ChannelHandlerContext ctx) { clientChannel = ctx.channel(); } /** * 注意在真实客户端请求一个页面的时候，此方法不止调用一次， * 这是TCP底层决定的（拆包/粘包） */ @Override public void channelRead(ChannelHandlerContext ctx, Object msg) { if (header.isComplete()) { /*如果在真实客户端的本次请求中已经解析过header了， 说明代理客户端已经在目标主机建立了连接，直接将真实客户端的数据写给目标主机*/ remoteChannel.writeAndFlush(msg); // just forward return; } ByteBuf in = (ByteBuf) msg; header.digest(in);/*解析目标主机信息*/ if (!header.isComplete()) { /*如果解析过一次header之后未完成解析，直接返回，释放buf*/ in.release(); return; } // disable AutoRead until remote connection is ready clientChannel.config().setAutoRead(false); if (header.isHttps()) { // if https, respond 200 to create tunnel clientChannel.writeAndFlush(Unpooled.wrappedBuffer("HTTP/1.1 200 Connection Established\r\n\r\n".getBytes())); } /** * * 下面为真实客户端第一次来到的时候，代理客户端向目标客户端发起连接 */ Bootstrap b = new Bootstrap(); b.group(clientChannel.eventLoop()) // use the same EventLoop .channel(clientChannel.getClass()) .handler(new HttpProxyRemoteHandler(clientChannel)); ChannelFuture f = b.connect(header.getHost(), header.getPort()); remoteChannel = f.channel(); f.addListener((ChannelFutureListener) future -> { if (future.isSuccess()) { // connection is ready, enable AutoRead clientChannel.config().setAutoRead(true); // forward header and remaining bytes if (!header.isHttps()) { //in读取一次缓冲区就没有了，header.byteBuf里面存了一份 remoteChannel.writeAndFlush(header.getByteBuf()); } } else { in.release(); clientChannel.close(); } }); } @Override public void channelInactive(ChannelHandlerContext ctx) { flushAndClose(remoteChannel); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable e) { e.printStackTrace(); flushAndClose(clientChannel); } private void flushAndClose(Channel ch) { if (ch != null && ch.isActive()) { ch.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE); } } } /** * 代理客户端请求目标主机处理器 */ private static class HttpProxyRemoteHandler extends ChannelInboundHandlerAdapter { private Channel clientChannel; private Channel remoteChannel; public HttpProxyRemoteHandler(Channel clientChannel) { this.clientChannel = clientChannel; } @Override public void channelActive(ChannelHandlerContext ctx) { this.remoteChannel = ctx.channel(); } @Override public void channelRead(ChannelHandlerContext ctx, Object msg) { clientChannel.writeAndFlush(msg); // just forward } @Override public void channelInactive(ChannelHandlerContext ctx) { flushAndClose(clientChannel); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable e) { e.printStackTrace(); flushAndClose(remoteChannel); } private void flushAndClose(Channel ch) { if (ch != null && ch.isActive()) { ch.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE); } } } /** * 真实主机的请求头信息 */ private static class HttpProxyClientHeader { private String method;//请求类型 private String host;//目标主机 private int port;//目标主机端口 private boolean https;//是否是https private boolean complete;//是否完成解析 private ByteBuf byteBuf = Unpooled.buffer(); private final StringBuilder lineBuf = new StringBuilder(); public String getMethod() { return method; } public String getHost() { return host; } public int getPort() { return port; } public boolean isHttps() { return https; } public boolean isComplete() { return complete; } public ByteBuf getByteBuf() { return byteBuf; } /** * 解析header信息，建立连接 HTTP 请求头如下 GETHTTP/1.1 Host: www.baidu.com User-Agent: curl/7.69.1 Accept: *//* Proxy-Connection:Keep-Alive HTTPS请求头如下 CONNECT www.baidu.com:443 HTTP/1.1 Host: www.baidu.com:443 User-Agent: curl/7.69.1 Proxy-Connection: Keep-Alive * @param in */ public void digest(ByteBuf in) { while (in.isReadable()) { if (complete) { throw new IllegalStateException("already complete"); } String line = readLine(in); System.out.println(line); if (line == null) { return; } if (method == null) { method = line.split(" ")[0]; // the first word is http method name https = method.equalsIgnoreCase("CONNECT"); // method CONNECT means https } if (line.startsWith("Host: ")) { String[] arr = line.split(":"); host = arr[1].trim(); if (arr.length == 3) { port = Integer.parseInt(arr[2]); } else if (https) { port = 443; // https } else { port = 80; // http } } if (line.isEmpty()) { if (host == null || port == 0) { throw new IllegalStateException("cannot find header \Host\"); } byteBuf = byteBuf.asReadOnly(); complete = true; break; } } System.out.println(this); System.out.println("--------------------------------------------------------------------------------"); } private String readLine(ByteBuf in) { while (in.isReadable()) { byte b = in.readByte(); byteBuf.writeByte(b); lineBuf.append((char) b); int len = lineBuf.length(); if (len >= 2 && lineBuf.substring(len - 2).equals("\r\n")) { String line = lineBuf.substring(0, len - 2); lineBuf.delete(0, len); return line; } } return null; } @Override public String toString() { return "HttpProxyClientHeader{" + "method=" + method + \ + ", host=" + host + \ + ", port=" + port + ", https=" + https + ", complete=" + complete + }; } } public static String convertByteBufToString(ByteBuf buf) { String str; if (buf.hasArray()) { // 处理堆缓冲区 str = new String(buf.array(), buf.arrayOffset() + buf.readerIndex(), buf.readableBytes()); } else { // 处理直接缓冲区以及复合缓冲区 byte[] bytes = new byte[buf.readableBytes()]; buf.getBytes(buf.readerIndex(), bytes); str = new String(bytes, 0, buf.readableBytes()); } return str; } }使用步骤
运行代理java HttpProxyServer即可在本机8443端口开启HTTP/HTTPS代理测试HTTP请求 curl -v -x 127.0.0.1 8443 测试HTTPS请求curl -v -x 127.0.0.1 8443 https://www.baidu.comHTTP和HTTPS的代理请求过程差异是比较大的