Python3 微信支付（小程序支付）V3接口

起因：

    因公司项目需要**网上充值**功能，从而对接**微信支付**，目前也只对接了微信支付的小程序支付功能，在网上找到的都是对接**微信支付V2版本**接口,与我所对接的接口版本不一致，无法使用，特此记录下微信支付完成功能，使用Django完成后端功能，此文章用于记录使用，

以下代码仅供参考，如若直接商用出现任何后果请自行承担，本人概不负责。

功能：

   调起微信支付，微信回调

**代码：
**1、准备工作：

mchid = "xxxxxx"                         # 商户号
pay_key = "xxxxxx"                       # 商户秘钥V3 使用V3接口必须使用V3秘钥
serial_num = "xxxxxx"                    # 证书序列号

# ======================前三个参数在微信支付中可找到===============================
# ============ 商户号(mchid ) 在账户中心——商户信息——微信支付商户号 （是纯数字） ==================
# ============= 商户秘钥(pay_key) 在账户中心——API安全——APIv3秘钥 （需手动设置） ===================
# ============= 证书序列号(serial_num) 在账户中心——API安全——API证书 （需手动申请,通过后会有串证书序列号），申请完成后需要把证书下载到项目中，便于使用 ===================

appid = "xxxxxx"                         # 微信小程序appid 
wx_secret ="xxxxxx"                      # 微信小程序秘钥
# ============= 微信小程序appid 在产品中心——AppID账号管理——添加关联的AppID  ===================     

WX_Pay_URL = "https://api.mch.weixin.qq.com/v3/pay/transactions/jsapi"
# ============= 微信支付调用地址,用于请求接收 预支付交易会话标识: prepay_id =================== 

WX_Notify_URL = "https://127.0.0.1:8000"  
# ============= 接收微信支付回调地址,必须是https ===================         

** *2、调起微信支付（后端只能请求微信支付接口向微信支付官方获取到*预支付交易会话标识**，并返回给前端，前端才能调起输入密码支付界面）

import json
import decimal
import traceback

import requests
from django.http import HttpResponse

def payment_view(request, *args, **kwargs):
    """
    微信支付（小程序）
    :param request:
    :param args:
    :param kwargs:
    :return:
    """
    try:
        reqdata = json.loads(request.body)
        # 前端参数
        jscode = reqdata["jscode"]  # 微信ID
        price = decimal.Decimal(reqdata["price"]).quantize(decimal.Decimal("0.00"))  # 充值金额,保留两位小数
        nickname = reqdata["nickname"]  # 微信昵称/支付宝名称 前端获取到返给后端做记录,可要可不要的字段
        paymode = reqdata["paymode"]  # 支付方式  1微信支付
        remark = reqdata["remark"]  # 支付内容描述
        
        # 根据jscode 获取openID
        rets = requests.get(url = "https://api.weixin.qq.com/sns/jscode2session?" \
              "appid=%s&secret=%s&js_code=%s" \
              "&grant_type=authorization_code" % (appid,wx_secret, js_code), timeout=3, verify=False)
        if not rets:
            return HttpResponse(general_error_msg(msg="未获取到微信信息"))

        # 0.获取支付的微信openid
        print(f"组织ID:{userinfo['orgid']}, jscode:{jscode}")
        wxuser = getappopenid(orgid, jscode)
        if wxuser:
            # session_key = wxuser["session_key"]
            openid = wxuser["openid"]
        else:
            return HttpResponse(general_error_msg(msg="未获取到微信用户信息"))

        # 1.以交易日期生成交易号
        orderno = order_num()
        # 2.生成新交易记录 paystatus 支付状态  1成功 0待支付 -1支付失败
        conorder.objects.create(orderno=orderno, openid=openid, openname=nickname,
                                paymode=paymode,goodstotalprice=price, paystatus=0, 
                                remark=remark,createtime=get_now_time(1))
        # 3.生成统一下单的报文body
        url = WX_Pay_URL
        body = {
            "appid": appid,
            "mchid": mchid,
            "description": remark,
            "out_trade_no": orderno,
            "notify_url": WX_Notify_URL + "/pay/notify",  # 后端接收回调通知的接口
            "amount": {"total": int(price * 100), "currency": "CNY"},  # 正式上线price要*100，微信金额单位为分（必须整型）。
            "payer": {"openid": openid},
        }
        data = json.dumps(body)

        headers, random_str, time_stamps = make_headers_v3(mchid, serial_num, data=data, method='POST')

        # 10.发送请求获得prepay_id
        try:
            response = requests.post(url, data=data, headers=headers)  # 获取预支付交易会话标识（prepay_id）
            print("预支付交易会话标识", response)
            if response.status_code == 200:
                wechatpay_serial, wechatpay_timestamp, wechatpay_nonce, wechatpay_signature, certificate, serial_no = check_wx_cert(
                    response, mchid, pay_key, serial_num)
                # 11.9签名验证
                if wechatpay_serial == serial_no:  # 应答签名中的序列号同证书序列号应相同
                    print('serial_no match')
                    try:
                        data3 = f"{wechatpay_timestamp}\n{wechatpay_nonce}\n{response.text}\n"
                        verify(data3, wechatpay_signature, certificate)
                        print('The signature is valid.')
                        # 12.生成调起支付API需要的参数并返回前端
                        res = {
                            'orderno': orderno,  # 订单号
                            'timeStamp': time_stamps,
                            'nonceStr': random_str,
                            'package': 'prepay_id=' + response.json()['prepay_id'],
                            'signType': "RSA",
                            'paySign': get_sign(f"{appid}\n{time_stamps}\n{random_str}\n{'prepay_id=' + response.json()['prepay_id']}\n"),
                        }
                        return HttpResponse(success_msg(msg="下单成功", total=0, data=res))
                    except Exception as e:
                        log.error(f"证书序列号验签失败{e}, {traceback.format_exc()}")
                        return HttpResponse(general_error_msg(msg="下单失败"))
                else:
                    log.error(f"证书序列号比对失败【请求头中证书序列号：{wechatpay_serial}；本地存储证书序列号：{serial_no}；】")
                    return HttpResponse(general_error_msg(msg="调起微信支付失败!"))
            else:
                log.error(f"获取预支付交易会话标识 接口报错【params：{data}；headers：{headers}；response：{response.text}】")
                return HttpResponse(general_error_msg(msg="调起微信支付失败!"))
        except Exception as e:
            log.error(f"调用微信支付接口超时【params：{data}；headers：{headers}；】：{e},{traceback.format_exc()}")
            return HttpResponse(general_error_msg(msg="微信支付超时!"))
    except Exception as e:
        log.error(f"微信支付接口报错：{e},{traceback.format_exc()}")
        return HttpResponse(general_error_msg(msg="微信支付接口报错!"))

3、相关方法

import base64
import random
import string
import time
import traceback
from datetime import datetime

import requests
from BaseMethods.log import log
from Crypto.PublicKey import RSA
from Crypto.Signature import pkcs1_15
from Cryptodome.Hash import SHA256
from sqlalchemy.util import b64encode
from cryptography.hazmat.primitives.ciphers.aead import AESGCM

# 各包版本
# django-ratelimit==3.0.1
# SQLAlchemy~=1.4.44
# pycryptodome==3.16.0
# pycryptodomex==3.16.0
# cryptography~=38.0.4
# Django~=3.2.4

# 获取唯一标识
def get_uuid(utype=0):
    """
    唯一码
    :param utype:
    :return:
    """
    if utype == 0:
        return uuid.uuid1()
    elif utype == 1:
        return str(uuid.uuid1())
    elif utype == 2:
        return str(uuid.uuid1().hex)
    elif utype == 3:
        return str((uuid.uuid5(uuid.NAMESPACE_DNS, str(uuid.uuid1()) + str(random.random()))))

# 获取当前时间
def get_now_time(type=0):
    """
    :param type: 类型0-5
    :return: yyyy-mm-dd HH:MM:SS;y-m-d H:M:S.f;y-m-d;ymdHMS;y年m月d日h时M分S秒
    """
    if type == 0:
        return datetime.datetime.now()
    elif type == 1:
        return datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    elif type == 2:
        return datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S.%f")
    elif type == 3:
        return datetime.datetime.now().strftime("%Y-%m-%d")
    elif type == 4:
        return datetime.datetime.now().strftime("%Y%m%d%H%M%S")
    elif type == 5:
        locale.setlocale(locale.LC_CTYPE, 'chinese')
        timestr = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
        t = time.strptime(timestr, "%Y-%m-%d %H:%M:%S")
        result = (time.strftime("%Y年%m月%d日%H时%M分%S秒", t))
        return result
    elif type == 6:
        return datetime.datetime.now().strftime("%Y%m%d")

# 重构系统jargon类，用于处理时间格式报错问题
class DateEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, datetime.datetime):
            return obj.strftime('%Y-%m-%d %H:%M:%S')
        elif isinstance(obj, datetime.date):
            return obj.strftime("%Y-%m-%d")
        elif isinstance(obj, Decimal):
            return float(obj)
        elif isinstance(obj, bytes):
            return str(obj, encoding='utf-8')
        elif isinstance(obj, uuid.UUID):
            return str(obj)
        elif isinstance(obj, datetime.time):
            return obj.strftime('%H:%M')
        elif isinstance(obj, datetime.timedelta):
            return str(obj)
        else:
            return json.JSONEncoder.default(self, obj)

def decrypt(nonce, ciphertext, associated_data, pay_key):
    """
    AES解密
    :param nonce:
    :param ciphertext:
    :param associated_data:
    :param pay_key:
    :return:
    """
    key = pay_key
    key_bytes = str.encode(key)
    nonce_bytes = str.encode(nonce)
    ad_bytes = str.encode(associated_data)
    data = base64.b64decode(ciphertext)
    aesgcm = AESGCM(key_bytes)
    return aesgcm.decrypt(nonce_bytes, data, ad_bytes)

def order_num():
    """
    生成订单号
    :return:
    """
    # 下单时间的年月日毫秒12+随机数8位
    now_time = datetime.now()
    result = str(now_time.year) + str(now_time.month) + str(now_time.day) + str(now_time.microsecond) + str(
        random.randrange(10000000, 99999999))
    return result

def get_sign(sign_str):
    """
    定义生成签名的函数
    :param sign_str:
    :return:
    """
    try:
        with open(r'static/cret/apiclient_key.pem') as f:
            private_key = f.read()
        rsa_key = RSA.importKey(private_key)
        signer = pkcs1_15.new(rsa_key)
        digest = SHA256.new(sign_str.encode('utf-8'))
        # sign = b64encode(signer.sign(digest)).decode('utf-8')
        sign = b64encode(signer.sign(digest))
        return sign
    except Exception as e:
        log.error("生成签名的函数方法报错【func：get_sign；sign_str：%s】：%s ==> %s" % (sign_str, e, traceback.format_exc()))

def check_wx_cert(response, mchid, pay_key, serial_no):
    """
    微信平台证书
    :param response: 请求微信支付平台所对应的的接口返回的响应值
    :param mchid: 商户号
    :param pay_key: 商户号秘钥
    :param serial_no: 证书序列号
    :return:
    """
    wechatpay_serial, wechatpay_timestamp, wechatpay_nonce, wechatpay_signature, certificate = None, None, None, None, None
    try:
        # 11.应答签名验证
        wechatpay_serial = response.headers['Wechatpay-Serial']  # 获取HTTP头部中包括回调报文的证书序列号
        wechatpay_signature = response.headers['Wechatpay-Signature']  # 获取HTTP头部中包括回调报文的签名
        wechatpay_timestamp = response.headers['Wechatpay-Timestamp']  # 获取HTTP头部中包括回调报文的时间戳
        wechatpay_nonce = response.headers['Wechatpay-Nonce']  # 获取HTTP头部中包括回调报文的随机串
        # 11.1.获取微信平台证书 （等于又把前面的跑一遍，实际上应是获得一次证书就存起来，不用每次都重新获取一次）
        url2 = "https://api.mch.weixin.qq.com/v3/certificates"
        # 11.2.生成证书请求随机串
        random_str2 = ''.join(random.choice(string.ascii_uppercase + string.digits) for _ in range(32))
        # 11.3.生成证书请求时间戳
        time_stamps2 = str(int(time.time()))
        # 11.4.生成请求证书的签名串
        data2 = ""
        sign_str2 = f"GET\n{'/v3/certificates'}\n{time_stamps2}\n{random_str2}\n{data2}\n"
        # 11.5.生成签名
        sign2 = get_sign(sign_str2)
        # 11.6.生成HTTP请求头
        headers2 = {
            "Content-Type": "application/json",
            "Accept": "application/json",
            "Authorization": 'WECHATPAY2-SHA256-RSA2048 '
                             + f'mchid="{mchid}",nonce_str="{random_str2}",signature="{sign2}",timestamp="{time_stamps2}",serial_no="{serial_no}"'
        }
        # 11.7.发送请求获得证书
        response2 = requests.get(url2, headers=headers2)  # 只需要请求头
        cert = response2.json()

        # 11.8.证书解密
        nonce = cert["data"][0]['encrypt_certificate']['nonce']
        ciphertext = cert["data"][0]['encrypt_certificate']['ciphertext']
        associated_data = cert["data"][0]['encrypt_certificate']['associated_data']
        serial_no = cert["data"][0]['serial_no']
        certificate = decrypt(nonce, ciphertext, associated_data, pay_key)
    except Exception as e:
        log.error(f"微信平台证书验证报错：{e}；{traceback.format_exc()}")
    return wechatpay_serial, wechatpay_timestamp, wechatpay_nonce, wechatpay_signature, certificate, serial_no

def verify(check_data, signature, certificate):
    """
    验签函数
    :param check_data:
    :param signature:
    :param certificate:
    :return:
    """
    key = RSA.importKey(certificate)  # 这里直接用了解密后的证书，但没有去导出公钥，似乎也是可以的。怎么导公钥还没搞懂。
    verifier = pkcs1_15.new(key)
    hash_obj = SHA256.new(check_data.encode('utf8'))
    return verifier.verify(hash_obj, base64.b64decode(signature))

def make_headers_v3(mchid, serial_num, data='', method='GET'):
    """
    定义微信支付请求接口中请求头认证
    :param mchid: 商户ID
    :param serial_num: 证书序列号
    :param data: 请求体内容
    :param method: 请求方法
    :return: headers(请求头)
    """
    # 4.定义生成签名的函数 get_sign(sign_str)
    # 5.生成请求随机串
    random_str = ''.join(random.choice(string.ascii_uppercase + string.digits) for _ in range(32))
    # 6.生成请求时间戳
    time_stamps = str(int(time.time()))
    # 7.生成签名串
    sign_str = f"{method}\n{'/v3/pay/transactions/jsapi'}\n{time_stamps}\n{random_str}\n{data}\n"
    # 8.生成签名
    sign = get_sign(sign_str)
    # 9.生成HTTP请求头
    headers = {
        'Content-Type': 'application/json',
        'Authorization': 'WECHATPAY2-SHA256-RSA2048 '
                         + f'mchid="{mchid}",nonce_str="{random_str}",signature="{sign}",timestamp="{time_stamps}",serial_no="{serial_num}"'
    }
    return headers, random_str, time_stamps

4、微信回调

import decimal
import json
import traceback

from django.http import HttpResponse

def notify_view(request, *args, **kwargs):
    """
    支付完成之后的通知(微信官方返回的数据)
    :param request:
    :param args:
    :param kwargs:
    :return:
    """
    try:
        # 1.获得支付通知的参数
        body = request.body
        data = bytes.decode(body, 'utf-8')
        newdata = json.loads(data)
        # newdata = {
        #     "id": "9d40acfd-13cb-5175-a5aa-6c421f794952",
        #     "create_time": "2023-01-06T15:12:49+08:00",
        #     "resource_type": "encrypt-resource",
        #     "event_type": "TRANSACTION.SUCCESS",
        #     "summary": "\xe6\x94\xaf\xe4\xbb\x98\xe6\x88\x90\xe5\x8a\x9f",
        #     "resource": {
        #         "original_type":
        #         "transaction",
        #         "algorithm": "AEAD_AES_256_GCM",
        #         "ciphertext": "UF5gLXfe8qBv9qxQsf+/Mb6as+vbIhUS8Dm25qGIJIIdXTorUUjqZH1+"
        #                       "jMQxkxma/Gn9bOxeAoQWPEuIoJ2pB328Iv90jmHTrouoP3L60mjNgGJS8d3H8i1zAPBXCpP4mgvgRANWsw4pAWj1lFM5BZr4aP+"
        #                       "pNMc5TdwreGBG3rO9sbCLXsSRfW8pVZ7IfPnhPDTOWP3P1k5ikHedcRt4/HP69oDBEe5RSsD93wO/"
        #                       "lrIwycStVHyecBaliwpVMRnNnRCXqhlalNJ3NJ6jcgy32fP1J+L90ntwGyqMmZUS71P5TN1H0iH5rXNpRY9IF3pvN+"
        #                       "lei5IS86wEoVXkmEsPcJrHaabn7rghxuZoqwuauMIiMwBLllnEmgXfAbJA4FJy+"
        #                       "OLhZPrMWMkkiNCLcL069QlvhLXYi/0V9PQVTnvtA5RLarj26s4WSqTZ2I5VGHbTqSIZvZYK3F275KEbQsemYETl18xwZ+"
        #                       "WAuSrYaSKN/pKykK37vUGtT3FeIoJup2c6M8Ghull3OcVmqCOsgvU7/pNjl1rLKEJB6t/X9avcHv+feikwQBtBmd/b2qCeSrEpM7US",
        #         "associated_data": "transaction",
        #         "nonce": "cKEdw8eV9Bh0"
        #     }
        # }
        nonce = newdata['resource']['nonce']
        ciphertext = newdata['resource']['ciphertext']
        associated_data = newdata['resource']['associated_data']

        try:
           payment = decrypt(nonce, ciphertext, associated_data, pay_key)
           break
        except Exception as e:
           print(e)
        if not payment:
            return HttpResponse({"code": "FAIL", "message": "失败"}, status=400)
        payment = eval(payment.decode('utf-8'))
        # payment = {
        #     "mchid": "xxxx",
        #     "appid": "xxxx",
        #     "out_trade_no": "20231654836163523608",
        #     "transaction_id": "4200001646202301065425000524",
        #     "trade_type": "JSAPI",
        #     "trade_state": "SUCCESS",
        #     "trade_state_desc": "\xe6\x94\xaf\xe4\xbb\x98\xe6\x88\x90\xe5\x8a\x9f",
        #     "bank_type": "OTHERS",
        #     "attach": "",
        #     "success_time": "2023-01-06T15:12:49+08:00",
        #     "payer": {
        #         "openid": "xxxxx"
        #     },
        #     "amount": {
        #         "total": 1,
        #         "payer_total": 1,
        #         "currency": "CNY",
        #         "payer_currency": "CNY"
        #     }
        # }
        orderno = payment['out_trade_no']
        zf_status = True if payment["trade_type"] == "SUCCESS" else False
        if zf_status:
            money = decimal.Decimal(int(payment["amount"]["payer_total"]) / 100).quantize(decimal.Decimal("0.00"))
        else:
            money = decimal.Decimal(0.0).quantize(decimal.Decimal("0.00"))
        # 7.回调报文签名验证
        # 同第一篇签名验证的代码
        wechatpay_serial, wechatpay_timestamp, wechatpay_nonce, wechatpay_signature, certificate = check_wx_cert(request, mchid, pay_key, serial_num)
        if wechatpay_serial == serial_num:  # 应答签名中的序列号同证书序列号应相同
            # 8.获得回调报文中交易号后修改已支付订单状态
            res = conorder.objects.filter(orderno=orderno, paystatus=-1).first()
            if res:
                res.paystatus = 1
                res.save()
            else:
                res.paystatus = -1
                res.save()
            # 9.项目业务逻辑
            return HttpResponse({"code": "SUCCESS", "message": "成功"})
        else:
            log.error(f"证书序列号比对失败【请求头中证书序列号：{wechatpay_serial}；本地存储证书序列号：{serial_num}；】")
            return HttpResponse({"code": "FAIL", "message": "失败"}, status=400)
    except Exception as e:
        log.error(f"微信回调接口报错：{e},{traceback.format_exc()}")
        return HttpResponse({"code": "FAIL", "message": "失败"}, status=400)

5、借鉴地址：

    在此非常感谢博主，文章链接如下：一文基本搞定python的django框架下微信支付v3的主要流程-1 - 知乎​​​​​​从去年底开始，下决心自己写代码来搞定自已策划的微信小程序” 来推鉴--投融资项目推荐服务平台“后，微信支付就成为挡在前面的一座大山。毕竟是从一个从没开发过一个程序的基本零基础，到要真正上线一个能商业运…https://zhuanlan.zhihu.com/p/402449405

6、请注意：

以上代码仅供参考，如若直接商用出现任何后果请自行承担，本人概不负责。