112 lines
3.6 KiB
Python
112 lines
3.6 KiB
Python
"""
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微信公众号 FastAPI 应用
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GET /wechat - 微信服务器验证（签名校验 + 返回 echostr）
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POST /wechat - 接收微信推送的消息和事件
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"""
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import hashlib
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import time
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import xml.etree.ElementTree as ET
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from fastapi import FastAPI, Request, Query, HTTPException
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from fastapi.responses import PlainTextResponse
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from config import WECHAT_TOKEN
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app = FastAPI(title="WeChat API", version="0.1.0")
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def verify_signature(signature: str, timestamp: str, nonce: str) -> bool:
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"""
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微信签名验证:
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1. 将 token、timestamp、nonce 三个参数字典序排序
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2. 拼成一个字符串
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3. sha1 加密
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4. 和 signature 对比
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"""
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if not WECHAT_TOKEN:
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return False
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items = sorted([WECHAT_TOKEN, timestamp, nonce])
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sha1 = hashlib.sha1("".join(items).encode()).hexdigest()
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return sha1 == signature
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@app.get("/wechat")
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async def wechat_verify(
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signature: str = Query(...),
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timestamp: str = Query(...),
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nonce: str = Query(...),
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echostr: str = Query(...),
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):
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"""GET: 微信服务器验证回调地址有效性"""
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if not verify_signature(signature, timestamp, nonce):
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raise HTTPException(status_code=403, detail="Invalid signature")
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# 验证通过，原样返回 echostr
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return PlainTextResponse(content=echostr)
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@app.post("/wechat")
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async def wechat_message(
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request: Request,
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signature: str = Query(...),
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timestamp: str = Query(...),
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nonce: str = Query(...),
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openid: str = Query(...),
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):
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"""POST: 接收微信推送的消息和事件"""
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# 验证签名
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if not verify_signature(signature, timestamp, nonce):
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raise HTTPException(status_code=403, detail="Invalid signature")
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# 解析 XML 消息体
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body = await request.body()
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root = ET.fromstring(body)
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msg_type = root.findtext("MsgType", "")
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from_user = root.findtext("FromUserName", "") # 发送方（用户 openid）
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to_user = root.findtext("ToUserName", "") # 接收方（公众号）
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content = root.findtext("Content", "")
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event = root.findtext("Event", "")
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event_key = root.findtext("EventKey", "")
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print(f"[WeChat] type={msg_type} from={from_user} event={event} content={content} key={event_key}")
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# 处理事件推送
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if msg_type == "event":
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if event == "subscribe":
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# 用户关注
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return _reply_text(from_user, to_user, "欢迎关注！")
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elif event == "unsubscribe":
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# 用户取关
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print(f"[WeChat] 用户取关: {from_user}")
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return PlainTextResponse(content="success")
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elif event == "SCAN":
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# 已关注用户扫码
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return _reply_text(from_user, to_user, f"扫码成功，场景值: {event_key}")
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elif event == "CLICK":
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# 菜单点击
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return _reply_text(from_user, to_user, f"点击了: {event_key}")
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# 处理文本消息
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if msg_type == "text":
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# 原样返回（echo 模式，方便测试）
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return _reply_text(from_user, to_user, f"你说: {content}")
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# 其他类型暂不处理
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return _reply_text(from_user, to_user, "收到")
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def _reply_text(from_user: str, to_user: str, content: str) -> PlainTextResponse:
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"""构造文本回复 XML"""
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xml = (
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"<xml>"
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f"<ToUserName><![CDATA[{from_user}]]></ToUserName>"
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f"<FromUserName><![CDATA[{to_user}]]></FromUserName>"
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f"<CreateTime>{int(time.time())}</CreateTime>"
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"<MsgType><![CDATA[text]]></MsgType>"
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f"<Content><![CDATA[{content}]]></Content>"
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"</xml>"
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)
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return PlainTextResponse(content=xml, media_type="application/xml")
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