wecom-ai-assistant/backend/app/routers/wecom.py

"""企业微信回调：GET 校验 + POST 消息回调（验签、解密、echo 回复、会话入库）。"""
import time
import logging
import random
import string
from fastapi import APIRouter, Request, Query, Depends
from fastapi.responses import PlainTextResponse
from sqlalchemy.ext.asyncio import AsyncSession

from app.database import get_db
from app.services.session_service import get_or_create_session, add_message
from app.services.wecom_crypto import (
    verify_and_decrypt_echostr,
    verify_signature,
    parse_encrypted_body,
    decrypt,
    parse_decrypted_xml,
    build_reply_xml,
    encrypt,
    make_reply_signature,
    build_encrypted_response,
)
from app.logging_config import get_trace_id

logger = logging.getLogger(__name__)
router = APIRouter()


@router.get("/callback")
def wecom_verify(
    request: Request,
    signature: str = Query(None, alias="signature"),
    msg_signature: str = Query(None, alias="msg_signature"),
    timestamp: str = Query(..., alias="timestamp"),
    nonce: str = Query(..., alias="nonce"),
    echostr: str = Query(..., alias="echostr"),
):
    """企业微信 GET 验签：校验签名并解密 echostr，原样返回明文。
    兼容 signature 和 msg_signature 两种参数名。
    """
    trace_id = get_trace_id()
    # 兼容 signature 和 msg_signature 两种参数名
    sig = msg_signature or signature
    if not sig:
        logger.warning(
            "wecom verify missing signature",
            extra={"trace_id": trace_id, "query_params": dict(request.query_params)},
        )
        return PlainTextResponse("", status_code=400)
    plain = verify_and_decrypt_echostr(sig, timestamp, nonce, echostr)
    if plain is None:
        logger.warning(
            "wecom verify failed",
            extra={"trace_id": trace_id, "timestamp": timestamp, "nonce": nonce},
        )
        return PlainTextResponse("", status_code=400)
    logger.info(
        "wecom verify success",
        extra={"trace_id": trace_id, "echostr_length": len(echostr)},
    )
    return PlainTextResponse(plain)


@router.post("/callback")
async def wecom_callback(
    request: Request,
    signature: str = Query(None, alias="signature"),
    msg_signature: str = Query(None, alias="msg_signature"),
    timestamp: str = Query(..., alias="timestamp"),
    nonce: str = Query(..., alias="nonce"),
    db: AsyncSession = Depends(get_db),
):
    """POST 消息回调：验签、解密、会话与消息入库、文本 echo 回复。
    兼容 signature 和 msg_signature 两种参数名。
    """
    trace_id = get_trace_id()
    # 兼容 signature 和 msg_signature 两种参数名
    sig = msg_signature or signature
    if not sig:
        logger.warning(
            "wecom post missing signature",
            extra={"trace_id": trace_id, "query_params": dict(request.query_params)},
        )
        return PlainTextResponse("", status_code=400)
    body = await request.body()
    encrypt_raw, err = parse_encrypted_body(body)
    if err:
        logger.warning(
            "wecom post parse error",
            extra={"trace_id": trace_id, "error": err},
        )
        return PlainTextResponse("", status_code=400)
    if not verify_signature(sig, timestamp, nonce, encrypt_raw):
        logger.warning(
            "wecom post verify failed",
            extra={"trace_id": trace_id, "timestamp": timestamp},
        )
        return PlainTextResponse("", status_code=400)
    try:
        plain_xml = decrypt(encrypt_raw)
    except Exception as e:
        logger.warning(
            "wecom decrypt error",
            extra={"trace_id": trace_id, "error": str(e)},
        )
        return PlainTextResponse("", status_code=400)
    msg = parse_decrypted_xml(plain_xml)
    if not msg:
        logger.warning(
            "wecom xml parse failed",
            extra={"trace_id": trace_id},
        )
        return PlainTextResponse("", status_code=400)
    to_user = msg.get("ToUserName", "")
    from_user = msg.get("FromUserName", "")  # external_userid
    msg_id = msg.get("MsgId", "")
    msg_type = msg.get("MsgType", "")
    content = (msg.get("Content") or "").strip()
    content_summary = content[:50] + "..." if len(content) > 50 else content
    
    # 记录日志：trace_id + external_userid + msgid + 内容摘要
    logger.info(
        "wecom message received",
        extra={
            "trace_id": trace_id,
            "external_userid": from_user,
            "msgid": msg_id,
            "msg_type": msg_type,
            "content_summary": content_summary or "(empty)",
        },
    )
    
    # 会话入库：external_user_id = from_user（客户）
    session = await get_or_create_session(db, from_user, msg.get("Contact"))
    await add_message(db, session.id, "user", content or "(非文本消息)")
    
    # Echo 文本：回复"已收到：{用户消息}"
    if msg_type == "text" and content:
        reply_content = f"已收到：{content}"
    else:
        reply_content = "已收到"
    
    await add_message(db, session.id, "assistant", reply_content)
    
    # 回复给客户（被动回复 XML）
    reply_xml = build_reply_xml(from_user, to_user, reply_content)
    enc = encrypt(reply_xml)
    ts = str(int(time.time()))
    reply_nonce = "".join(random.choices(string.ascii_letters + string.digits, k=16))
    sig = make_reply_signature(enc, ts, reply_nonce)
    resp_xml = build_encrypted_response(enc, sig, ts, reply_nonce)
    
    logger.info(
        "wecom reply sent",
        extra={
            "trace_id": trace_id,
            "external_userid": from_user,
            "msgid": msg_id,
            "reply_summary": reply_content[:50] + "..." if len(reply_content) > 50 else reply_content,
        },
    )
    
    return PlainTextResponse(resp_xml, media_type="application/xml")