tencent-ad-server/server/src/main/java/com/tzld/rta/controller/rta/RtaController.java

package com.tzld.rta.controller.rta;

import com.tzld.rta.codec.RtaProtobufCodec;
import com.tzld.rta.model.RtaRequestModel;
import com.tzld.rta.model.RtaResponseModel;
import com.tzld.rta.service.RtaService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import javax.servlet.http.HttpServletRequest;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;

/**
 * 腾讯RTA接入Controller
 * <p>
 * 协议要求:
 * - HTTP/1.1 长连接（Keep-Alive）
 * - POST 方法，Content-Type: application/x-protobuf
 * - 响应始终返回 HTTP 200（异常时也需 200）
 * - 超时时间: 60ms（含网络传输）
 * - 超时率/错误率需低于 2%
 * <p>
 * 接口地址: POST /rta/bid
 */
@Slf4j
@RestController
@RequestMapping("/rta")
public class RtaController {

    private static final String CONTENT_TYPE_PROTOBUF = "application/x-protobuf";

    @Autowired
    private RtaService rtaService;

    /**
     * RTA 竞价接口
     * 腾讯广告系统通过此接口实时查询设备是否参竞
     *
     * @param httpRequest HTTP请求
     * @return protobuf 格式响应
     */
    @PostMapping(
            value = "/bid",
            consumes = {CONTENT_TYPE_PROTOBUF, MediaType.APPLICATION_OCTET_STREAM_VALUE, MediaType.ALL_VALUE},
            produces = CONTENT_TYPE_PROTOBUF
    )
    public ResponseEntity<byte[]> bid(HttpServletRequest httpRequest) {
        long startTime = System.currentTimeMillis();
        try {
            // 1. 读取请求体
            byte[] requestBytes = readRequestBody(httpRequest);
            if (requestBytes == null || requestBytes.length == 0) {
                return buildEmptyResponse();
            }
            // 2. 解码 protobuf 请求
            RtaRequestModel request = RtaProtobufCodec.decodeRequest(requestBytes);
            // 3. 业务处理
            RtaResponseModel response = rtaService.process(request);
            // 4. 编码 protobuf 响应
            byte[] responseBytes = RtaProtobufCodec.encodeResponse(response);
            return ResponseEntity.ok()
                    .header("Content-Type", CONTENT_TYPE_PROTOBUF)
                    .header("Connection", "keep-alive")
                    .header("Content-Length", String.valueOf(responseBytes.length))
                    .body(responseBytes);
        } catch (Exception e) {
            log.error("[RTA] bid error, cost={}ms", System.currentTimeMillis() - startTime, e);
            // 出错时也要返回 200，返回空 protobuf（视为参竞，符合RTA规范）
            return buildEmptyResponse();
        }
    }

    /**
     * 读取请求体字节
     */
    private byte[] readRequestBody(HttpServletRequest request) throws Exception {
        try (InputStream is = request.getInputStream()) {
            ByteArrayOutputStream buffer = new ByteArrayOutputStream();
            byte[] chunk = new byte[4096];
            int n;
            while ((n = is.read(chunk)) != -1) {
                buffer.write(chunk, 0, n);
            }
            return buffer.toByteArray();
        }
    }

    /**
     * 构建空的成功响应（空protobuf body = code:0）
     */
    private ResponseEntity<byte[]> buildEmptyResponse() {
        try {
            byte[] emptyResponse = RtaProtobufCodec.encodeResponse(
                    RtaResponseModel.builder().code(0).build()
            );
            return ResponseEntity.ok()
                    .header("Content-Type", CONTENT_TYPE_PROTOBUF)
                    .header("Connection", "keep-alive")
                    .header("Content-Length", String.valueOf(emptyResponse.length))
                    .body(emptyResponse);
        } catch (Exception ex) {
            // 兜底，返回纯空body
            return ResponseEntity.ok()
                    .header("Content-Type", CONTENT_TYPE_PROTOBUF)
                    .header("Connection", "keep-alive")
                    .body(new byte[0]);
        }
    }
}