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feat:使用魔数来进行协议嗅探->TCP = 0xAABBCCDD,HTTP/2 = 0x50524920
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Lines changed: 131 additions & 3 deletions

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‎rpc-transport-netty/src/main/java/com/xiaoyu/rpc/core/protocol/ProtocolDetectHandler.java‎

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package com.xiaoyu.rpc.core.protocol;
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import com.xiaoyu.rpc.core.server.NettyRpcHandler;
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import io.netty.buffer.ByteBuf;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.handler.codec.ByteToMessageDecoder;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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import java.util.List;
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/**
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* 协议嗅探器 —— 服务端自动识别多种协议
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* <p>
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* 原理：连接建立后，偷看（peek）入站数据的前几个字节，根据特征判断协议类型：
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* <ul>
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* <li>0xAABBCCDD → TCP 私有协议（NettyProtocol）</li>
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* <li>0x50524920 ("PRI ") → HTTP/2 Connection Preface（Http2Protocol 或
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* GrpcProtocol）</li>
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* <li>HTTP 方法名（GET / POST / PUT / HEAD / DELETE / OPTIONS / PATCH）→
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* HTTP/1.1（HttpProtocol）</li>
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* </ul>
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* 识别后动态配置 pipeline 并移除自身，后续按确定的协议处理。
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* <p>
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* 注意：gRPC 底层也是 HTTP/2 传输，无法在字节层面与普通 HTTP/2 区分。
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* 通过构造函数的 {@code http2ProtocolName} 参数控制 HTTP/2 连接的处理方式。
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*/
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public class ProtocolDetectHandler extends ByteToMessageDecoder {
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private static final Logger log = LoggerFactory.getLogger(ProtocolDetectHandler.class);
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/** TCP 私有协议魔数，与 NettyRpcEncoder/NettyRpcDecoder 一致 */
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private static final int NETTY_MAGIC = 0xAABBCCDD;
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/** HTTP/2 Connection Preface 前 4 字节: "PRI " = 0x50524920 */
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private static final int HTTP2_MAGIC = 0x50524920;
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// 常见 HTTP/1.1 方法的首字母 ASCII 码
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private static final byte BYTE_G = 'G'; // GET
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private static final byte BYTE_P = 'P'; // POST, PUT, PATCH
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private static final byte BYTE_D = 'D'; // DELETE
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private static final byte BYTE_H = 'H'; // HEAD
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private static final byte BYTE_O = 'O'; // OPTIONS
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private static final byte BYTE_T = 'T'; // TRACE
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private static final byte BYTE_C = 'C'; // CONNECT
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/**
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* 当检测到 HTTP/2 Connection Preface 时使用的协议名。
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* 因为 gRPC 底层也是 HTTP/2，无法在字节层面区分，
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* 所以通过这个参数指定：可以是 "http2" 或 "grpc"。
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* 默认为 "http2"。
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*/
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private final String http2ProtocolName;
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/**
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* 默认构造函数，HTTP/2 连接使用 Http2Protocol 处理
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*/
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public ProtocolDetectHandler() {
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this("http2");
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}
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/**
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* 指定 HTTP/2 连接的处理协议
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*
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* @param http2ProtocolName HTTP/2 连接使用的协议名（"http2" 或 "grpc"）
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*/
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public ProtocolDetectHandler(String http2ProtocolName) {
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this.http2ProtocolName = http2ProtocolName;
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}
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@Override
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protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
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// 至少需要 4 字节才能判断协议类型
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if (in.readableBytes() < 4) {
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return;
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}
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// 偷看前 4 字节，不消费（不移动 readerIndex）
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int magic = in.getInt(in.readerIndex());
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byte firstByte = in.getByte(in.readerIndex());
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if (magic == NETTY_MAGIC) {
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log.info("检测到 TCP 私有协议连接, 远程地址: {}", ctx.channel().remoteAddress());
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configProtocol(ctx, "netty");
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} else if (magic == HTTP2_MAGIC) {
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log.info("检测到 HTTP/2 协议连接 (使用 {} 处理), 远程地址: {}",
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http2ProtocolName, ctx.channel().remoteAddress());
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configProtocol(ctx, http2ProtocolName);
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} else if (isHttpMethod(firstByte)) {
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log.info("检测到 HTTP/1.1 协议连接, 远程地址: {}", ctx.channel().remoteAddress());
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configProtocol(ctx, "http");
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} else {
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log.warn("未知协议, 首字节: 0x{}, 关闭连接, 远程地址: {}",
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Integer.toHexString(magic), ctx.channel().remoteAddress());
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in.clear();
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ctx.close();
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}
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}
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/**
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* 判断首字节是否可能是 HTTP/1.1 方法名的开头
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*/
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private boolean isHttpMethod(byte firstByte) {
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return firstByte == BYTE_G // GET
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|| firstByte == BYTE_P // POST, PUT, PATCH
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|| firstByte == BYTE_D // DELETE
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|| firstByte == BYTE_H // HEAD
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|| firstByte == BYTE_O // OPTIONS
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|| firstByte == BYTE_T // TRACE
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|| firstByte == BYTE_C; // CONNECT
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}
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/**
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* 根据协议名动态配置 pipeline，然后移除自身
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*/
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private void configProtocol(ChannelHandlerContext ctx, String protocolName) {
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Protocol protocol = ProtocolFactory.getProtocol(protocolName);
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// 先移除自身，再配置协议的编解码器和 Handler
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ctx.pipeline().remove(this);
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protocol.config(ctx.pipeline(), true, new NettyRpcHandler());
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}
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}

‎rpc-transport-netty/src/main/java/com/xiaoyu/rpc/core/transport/netty/NettyTransportServer.java‎

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import com.xiaoyu.rpc.core.config.RpcConfig;
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import com.xiaoyu.rpc.core.protocol.Protocol;
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import com.xiaoyu.rpc.core.protocol.ProtocolDetectHandler;
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import com.xiaoyu.rpc.core.protocol.ProtocolFactory;
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import com.xiaoyu.rpc.core.server.NettyRpcHandler;
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import com.xiaoyu.rpc.core.transport.TransportServer;
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.childHandler(new ChannelInitializer<SocketChannel>() {
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@Override
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protected void initChannel(SocketChannel ch) {
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// 协议实现通过配置切换，服务端业务处理统一复用 NettyRpcHandler
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String protocolName = RpcConfig.getInstance().getProtocol();
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Protocol protocol = ProtocolFactory.getProtocol(protocolName);
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protocol.config(ch.pipeline(), true, new NettyRpcHandler());
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if ("auto".equalsIgnoreCase(protocolName)) {
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// 自动嗅探模式：先放嗅探器，连接建立后根据首字节判断协议
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ch.pipeline().addLast(new ProtocolDetectHandler());
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} else {
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// 指定协议模式：保持原有行为
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Protocol protocol = ProtocolFactory.getProtocol(protocolName);
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protocol.config(ch.pipeline(), true, new NettyRpcHandler());
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}
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}
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});
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