src/main/java/com/example/myproject/controller/TrackerController.java

package com.example.myproject.controller;

import cn.hutool.core.util.HexUtil;

import com.example.myproject.dto.param.AnnounceRequest;
//import com.example.myproject.service.AnnounceService;
//import com.example.myproject.utils.BinaryFieldUtil;
import com.turn.ttorrent.bcodec.BEncoder;
//import com.example.myproject.utils.IPUtils;




import javax.servlet.http.HttpServletRequest;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.client.RestTemplate;

import java.nio.ByteBuffer;
import java.util.List;
import java.util.Map;
import java.util.Optional;

@Slf4j
@RestController
@RequiredArgsConstructor
public class TrackerController {

//    private final AnnounceService announceService;

    private final RestTemplate restTemplate = new RestTemplate();

    @GetMapping("/announce")
    public ResponseEntity<byte[]> announce(HttpServletRequest request,
                                           @ModelAttribute AnnounceRequest announceRequest,
                                           @RequestHeader(name = "User-Agent") String ua,
                                           @RequestHeader(name = "want-digest", required = false) String wantDigest) {

        // 1. 获取请求参数原始字符串（方便解析peerId、infoHash等）
        String queryStrings = request.getQueryString();
        log.info("收到announce汇报：" + queryStrings);
        //收到announce汇报：passkey=1&info_hash=%c8%8e%8ak8%09%97%1b%ab4%3a%a2%c3%bf%c3%22%05%f2j%d1&peer_id=-qB453A-9nl.HBf73dry&port=62128&uploaded=0&downloaded=0&left=1711543&corrupt=0&key=A0B2541D&event=started&numwant=200&compact=1&no_peer_id=1&supportcrypto=1&redundant=0
        //
        // 2. 获取客户端IP
        // 3. 提取peerId和infoHash（二进制字段）
//        byte[] peerId = BinaryFieldUtil.matchPeerId(queryStrings);
//        String peerIdHex = HexUtil.encodeHexStr(peerId);
//        byte[] infoHash = BinaryFieldUtil.matchInfoHash(queryStrings);

//        log.info("peerid：" + peerId);
//        log.info("infohash" + infoHash);

//        String ipAddr = IPUtils.getIpAddr();
//
//
//
//        // 4. 设置AnnounceRequest其他字段
//        announceRequest.setSeeder(announceRequest.getLeft() != null && announceRequest.getLeft().equals(0L));
//        announceRequest.setInfoHash(infoHash);
//        announceRequest.setPeerId(peerId);
//        announceRequest.setPeerIdHex(peerIdHex);
//        announceRequest.setRemoteAddr(ipAddr);
//        announceRequest.setWantDigest(wantDigest);
//        announceRequest.setUserAgent(ua);

//        // 5. 先调用业务层处理，比如记录用户状态
//        announceService.announce(announceRequest);

        // 6. 转发请求到真正tracker(6969端口)

        // 构造转发URL
        String trackerUrl = "http://localhost:6969/announce" + (queryStrings != null ? "?" + queryStrings : "");

        // 使用RestTemplate发起GET请求，直接获取二进制响应（bencode）
        ResponseEntity<byte[]> trackerResponse = restTemplate.getForEntity(trackerUrl, byte[].class);

        // 7. 直接将tracker返回的二进制数据，作为响应返回给客户端
        return ResponseEntity.ok()
                .header("Content-Type", "text/plain") // bencode通常用text/plain，或者 application/x-bittorrent
                .body(trackerResponse.getBody());

    }
}