178 lines
6.7 KiB
Python
178 lines
6.7 KiB
Python
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# =============================================================================
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# 企微IT智能服务台 — 百度语音识别（ASR）API
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# =============================================================================
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# 说明：接收前端上传的 PCM 音频数据，调用百度 ASR API 转换为文字
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# 1. POST /api/voice/asr — 语音转文字（上传PCM音频，返回识别文字）
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#
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# 音频格式要求：PCM, 16kHz, 16-bit, 单声道
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# 百度ASR凭证通过环境变量配置（BAIDU_ASR_APP_ID/API_KEY/SECRET_KEY）
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# access_token 缓存在 Redis（key=baidu:asr:token，TTL=30天）
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# =============================================================================
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import logging
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from typing import Optional
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import httpx
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from fastapi import APIRouter, File, HTTPException, UploadFile
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from app.config import settings
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from app.utils.response import success_response, error_response
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router = APIRouter(prefix="/voice", tags=["语音识别"])
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logger = logging.getLogger(__name__)
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# --------------------------------------------------------------------------
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# 百度 ASR 配置常量
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# --------------------------------------------------------------------------
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# 百度 ASR 极速版 API 端点（raw binary POST 方式）
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BAIDU_ASR_API_URL = "https://vop.baidu.com/pro_api"
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# 百度 OAuth2 token 获取端点
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BAIDU_TOKEN_URL = "https://aip.baidubce.com/oauth/2.0/token"
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# dev_pid=80001 表示普通话极速版
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BAIDU_ASR_DEV_PID = "80001"
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# Redis 缓存 key
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BAIDU_TOKEN_CACHE_KEY = "baidu:asr:token"
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# token 缓存 TTL（30天，秒）— 与百度 token有效期一致
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BAIDU_TOKEN_TTL = 2592000
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async def get_baidu_token() -> str:
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"""获取百度 ASR access_token，带 Redis 缓存。
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优先从 Redis 读取缓存的 token（TTL 30天）；
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缓存不存在时调用百度 OAuth2 接口获取新 token 并缓存。
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Returns:
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str: 百度 ASR access_token
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Raises:
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HTTPException: 获取 token 失败时抛出 500 错误
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"""
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redis = settings.create_redis_client()
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try:
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# 1. 尝试从 Redis 缓存读取 token
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cached_token: Optional[str] = await redis.get(BAIDU_TOKEN_CACHE_KEY)
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if cached_token:
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logger.debug("[BaiduASR] 使用缓存的 access_token")
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return cached_token
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# 2. 缓存不存在，调用百度 OAuth2 获取新 token
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logger.info("[BaiduASR] 缓存未命中，请求新 access_token")
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async with httpx.AsyncClient(timeout=10) as client:
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resp = await client.post(
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BAIDU_TOKEN_URL,
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params={
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"grant_type": "client_credentials",
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"client_id": settings.baidu_asr_api_key,
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"client_secret": settings.baidu_asr_secret_key,
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},
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)
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data = resp.json()
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token = data.get("access_token")
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if not token:
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error_msg = data.get("error_description", "未知错误")
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logger.error(f"[BaiduASR] 获取 access_token 失败: {error_msg}")
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raise HTTPException(
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status_code=500,
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detail=f"获取百度ASR token失败: {error_msg}",
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)
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# 3. 缓存 token 到 Redis（TTL 30天）
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await redis.set(BAIDU_TOKEN_CACHE_KEY, token, ex=BAIDU_TOKEN_TTL)
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logger.info("[BaiduASR] access_token 已缓存到 Redis（TTL=30天）")
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return token
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finally:
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# 关闭 Redis 连接（每次创建新客户端，用完即关）
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await redis.aclose()
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@router.post("/asr")
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async def transcribe_audio(
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audio: UploadFile = File(..., description="PCM 音频数据（16kHz, 16-bit, mono）"),
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):
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"""语音转文字 — 上传 PCM 音频，返回百度 ASR 识别结果。
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处理流程：
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1. 接收前端上传的 PCM 音频数据（multipart/form-data，字段名 audio）
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2. 获取百度 access_token（Redis 缓存，TTL 30天）
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3. 调用百度 ASR API（raw binary POST 方式）
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4. 解析返回结果，返回识别文字
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**请求格式**: multipart/form-data
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**字段**: audio — PCM 音频文件（16kHz, 16-bit, 单声道）
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**成功响应**: {code: 0, data: {text: "识别的文字"}, message: "success"}
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**错误响应**: {code: 3001, data: null, message: "百度ASR错误: xxx"}
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Args:
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audio: FastAPI UploadFile 对象，包含 PCM 音频数据
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Returns:
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Dict: 统一响应格式
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"""
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# 1. 读取 PCM 音频数据
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pcm_data = await audio.read()
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if not pcm_data:
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raise HTTPException(status_code=400, detail="未收到音频数据")
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logger.info(
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f"[BaiduASR] 收到音频数据: {len(pcm_data)} bytes, "
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f"filename={audio.filename}"
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)
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# 2. 获取百度 access_token
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try:
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token = await get_baidu_token()
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except HTTPException:
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raise
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except Exception as e:
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logger.error(f"[BaiduASR] 获取 token 异常: {e}")
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return error_response(code=3001, message=f"获取百度ASR token失败: {str(e)}")
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# 3. 调用百度 ASR API（raw binary POST）
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try:
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async with httpx.AsyncClient(timeout=30) as client:
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resp = await client.post(
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BAIDU_ASR_API_URL,
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params={
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"dev_pid": BAIDU_ASR_DEV_PID,
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"cuid": settings.baidu_asr_app_id,
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"token": token,
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},
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content=pcm_data,
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headers={"Content-Type": "audio/pcm;rate=16000"},
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)
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result = resp.json()
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# 4. 解析返回结果
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# 百度 ASR 返回格式: {"err_no": 0, "result": ["识别的文字"]}
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# err_no=0 表示成功，非0表示错误
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if result.get("err_no") != 0:
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err_msg = result.get("err_msg", "未知错误")
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err_no = result.get("err_no", -1)
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logger.error(f"[BaiduASR] 识别失败: err_no={err_no}, err_msg={err_msg}")
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return error_response(
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code=3001,
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message=f"百度ASR错误: {err_msg}",
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)
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# 成功：提取识别文字
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text_list = result.get("result", [])
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recognized_text = text_list[0] if text_list else ""
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logger.info(
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f"[BaiduASR] 识别成功: text='{recognized_text[:50]}...' "
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f"(len={len(recognized_text)})"
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)
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return success_response(data={"text": recognized_text})
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except httpx.TimeoutException:
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logger.error("[BaiduASR] 调用百度 ASR API 超时（30秒）")
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return error_response(code=3001, message="百度ASR识别超时，请重试")
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except Exception as e:
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logger.error(f"[BaiduASR] 调用百度 ASR API 异常: {e}")
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return error_response(
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code=3001,
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message=f"语音识别失败: {str(e)}",
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)
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