很多网站里都有金币、积分之类的虚拟货币，获取这些往往需要充值。那么问题来了，如何在Django中对接支付宝实现支付宝充值金币的功能呢？网上很多资料都是电商的，那些都会带有订单系统之类比较复杂，而充值金币功能不需要实现那么多功能。

效果图如下：

现在就来实现Django对接支付宝支付功能吧！

登录支付宝开放平台

点击进入蚂蚁金服开放平台https://open.alipay.com/platform/home.htm
进入支付宝沙箱环境https://openhome.alipay.com/platform/appDaily.htm?tab=info

如图，这里是你沙箱环境的配置，左侧沙箱工具有沙箱支付宝安卓版下载，沙箱账号是你的测试账号。

下载支付宝开放平台开发助手

点击打开下载链接

打开工具，生成密钥，然后妥善保管好！！

保存密钥

把刚刚那个应用公钥2048重命名为：pub_2048.txt，把应用私钥2048重命名为：private_2048.txt，把这两个文件放在项目目录下。
注意：密钥的开始和结束一定要加上如下的字符串！！！

-----BEGIN PRIVATE KEY-----
这里粘贴里面的密钥
-----END PRIVATE KEY-----

复制支付宝的公钥并保存

把这段支付宝公钥复制，重命名为alipay_key_2048.txt，保存到项目目录中，注意加上如下字符串

-----BEGIN PRIVATE KEY-----
这里粘贴里面的密钥
-----END PRIVATE KEY-----

设置公钥

把刚刚的pub_2048.txt里面的字符串复制到如下：

调试支付宝支付接口

from datetime import datetime


from Crypto.PublicKey import RSA
from Crypto.Signature import PKCS1_v1_5
from Crypto.Hash import SHA256
from urllib.parse import quote_plus
from base64 import decodebytes, encodebytes

import json


class AliPay(object):
    """
    支付宝支付接口
    """

    def __init__(self, appid, app_notify_url, app_private_key_path,
                 alipay_public_key_path, return_url, debug=False):
        self.appid = appid
        self.app_notify_url = app_notify_url
        self.app_private_key_path = app_private_key_path
        self.app_private_key = None
        self.return_url = return_url
        with open(self.app_private_key_path) as fp:
            self.app_private_key = RSA.importKey(fp.read())

        self.alipay_public_key_path = alipay_public_key_path
        with open(self.alipay_public_key_path) as fp:
            self.alipay_public_key = RSA.import_key(fp.read())

        if debug is True:
            self.__gateway = "https://openapi.alipaydev.com/gateway.do"
        else:
            self.__gateway = "https://openapi.alipay.com/gateway.do"

    def direct_pay(self, subject, out_trade_no, total_amount, return_url=None, **kwargs):
        biz_content = {
            "subject": subject,
            "out_trade_no": out_trade_no,
            "total_amount": total_amount,
            "product_code": "FAST_INSTANT_TRADE_PAY",
            # "qr_pay_mode":4
        }

        biz_content.update(kwargs)
        data = self.build_body("alipay.trade.page.pay", biz_content, self.return_url)
        return self.sign_data(data)

    def build_body(self, method, biz_content, return_url=None):
        data = {
            "app_id": self.appid,
            "method": method,
            "charset": "utf-8",
            "sign_type": "RSA2",
            "timestamp": datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
            "version": "1.0",
            "biz_content": biz_content
        }

        if return_url is not None:
            data["notify_url"] = self.app_notify_url
            data["return_url"] = self.return_url

        return data

    def sign_data(self, data):
        data.pop("sign", None)
        # 排序后的字符串
        unsigned_items = self.ordered_data(data)
        unsigned_string = "&".join("{0}={1}".format(k, v) for k, v in unsigned_items)
        sign = self.sign(unsigned_string.encode("utf-8"))
        # ordered_items = self.ordered_data(data)
        quoted_string = "&".join("{0}={1}".format(k, quote_plus(v)) for k, v in unsigned_items)

        # 获得最终的订单信息字符串
        signed_string = quoted_string + "&sign=" + quote_plus(sign)
        return signed_string

    def ordered_data(self, data):
        complex_keys = []
        for key, value in data.items():
            if isinstance(value, dict):
                complex_keys.append(key)

        # 将字典类型的数据dump出来
        for key in complex_keys:
            data[key] = json.dumps(data[key], separators=(',', ':'))

        return sorted([(k, v) for k, v in data.items()])

    def sign(self, unsigned_string):
        # 开始计算签名
        key = self.app_private_key
        signer = PKCS1_v1_5.new(key)
        signature = signer.sign(SHA256.new(unsigned_string))
        # base64 编码，转换为unicode表示并移除回车
        sign = encodebytes(signature).decode("utf8").replace("\n", "")
        return sign

    def _verify(self, raw_content, signature):
        # 开始计算签名
        key = self.alipay_public_key
        signer = PKCS1_v1_5.new(key)
        digest = SHA256.new()
        digest.update(raw_content.encode("utf8"))
        if signer.verify(digest, decodebytes(signature.encode("utf8"))):
            return True
        return False

    def verify(self, data, signature):
        if "sign_type" in data:
            sign_type = data.pop("sign_type")
        # 排序后的字符串
        unsigned_items = self.ordered_data(data)
        message = "&".join(u"{}={}".format(k, v) for k, v in unsigned_items)
        return self._verify(message, signature)


def get_alipay_url(app_id, order_sn, order_mount):
    alipay = AliPay(
        appid=app_id,
        app_notify_url="http://127.0.0.1:8000/alipay/return/",
        app_private_key_path="../trade/keys/private_2048.txt",
        alipay_public_key_path="../trade/keys/alipay_key_2048.txt",  # 支付宝的公钥，验证支付宝回传消息使用，不是你自己的公钥,
        debug=True,  # 默认False,
        return_url="http://127.0.0.1:8000/alipay/return/"
    )

    url = alipay.direct_pay(
        subject=order_sn,
        out_trade_no=order_sn,
        total_amount=order_mount,
    )
    re_url = "https://openapi.alipaydev.com/gateway.do?{data}".format(data=url)

    return re_url


if __name__ == "__main__":
    url = get_alipay_url(
        '2016092600597838',
        '201902923423436',
        1.00
    )
    print(url)

如果输出的url能够打开并且使用沙箱账号支付，说明前面的配置成功了，可以进行视图的编写。

设计数据库订单模型

from django.db import models
from django.conf import settings
from django.utils.encoding import python_2_unicode_compatible

from questioning.utils.models import CreatedUpdatedMixin

@python_2_unicode_compatible
class OrderInfo(CreatedUpdatedMixin, models.Model):
    '''
    充值订单详情
    '''
    ORDER_STATUS = (
    ('TRADE_SUCCESS', '交易支付成功'),
    ('TRADE_CLOSED', '未付款交易超时关闭'),
    ('WAIT_BUYER_PAY', '交易创建'),
    ('TRADE_FINISHED', '交易结束'),
    ('paying', '待支付'),
)
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, verbose_name='用户')
    order_sn = models.CharField(max_length=30, null=True, blank=True, unique=True, verbose_name='订单号')
    trade_no = models.CharField(max_length=100, unique=True, null=True, blank=True, verbose_name='支付订单号')

    pay_status = models.CharField(choices=ORDER_STATUS, max_length=40, verbose_name='订单状态', default='paying')
    order_mount = models.DecimalField(verbose_name="充值金额", max_digits=10,
                                decimal_places=2, default=0.00)


    class Meta:
        verbose_name = "充值订单"
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.order_sn

注意充值的金额要设置为models.DecimalField货币类型
然后导入到数据库中

视图函数编写

class AlipayView(LoginRequiredMixin, AuthorRequiredMixin, View):
    """
    支付宝支付
    get方法实现支付宝return_url，如果没有实现也无所谓，post同样可以更新状态
    post方法实现支付宝notify_url，异步更新

    支付宝返回的url如下：
    #http://127.0.0.1:8000/alipay/return/?
    # charset=utf-8&
    # out_trade_no=201902923423436&
    # method=alipay.trade.page.pay.return&
    # total_amount=1.00&
    # sign=CDBMY9NBsp4KICdQoBEVxGWobd0N8y4%2BU09stzUWwlNtLr7ZpELJdM5js20wXv%2FCPp0FGPbRW1YS9DRx0CnKJULZZMqysBUMH2FL39sS0Fgstgy1ydTs7ySXdHziJV0inI%2BDWAsebQqtjk5gQEweUstc%2B%2BnzjdgAulpvWzfJsbknS%2BqUfktSdF2ZOWGhr1CFlfsMFEDS2nzQv4K3E%2BNaeylkzUnRe9M1sjIL%2FYR0wVZ5A3OfHLPf9HzC2B8%2FLu4g7N5Vctkqp2aerDvIkN5SNmDnRGyjOt2b%2BOsLMqG4X06JSsrZT6Ln8PimsrkSOIGbj0gCqscx7BwZfmCQePlCw%3D%3D&
    # trade_no=2019082622001426981000041778&
    # auth_app_id=2016092600597838&
    # version=1.0&app_id=2016092600597838&
    # sign_type=RSA2&
    # seller_id=2088102177296610&
    # timestamp=2019-08-26+13%3A51%3A01
    """
    def dispatch(self, request, *args, **kwargs):
        self.alipay = AliPay(
            appid=settings.ALIPAY_APPID,
            app_notify_url=settings.APP_NOTIFY_URL,
            app_private_key_path=settings.APP_PRIVATE_KEY_PATH,
            alipay_public_key_path=settings.ALIPAY_PUBLIC_KEY_PATH,
            debug=settings.ALIPAY_DEBUG,
            return_url=settings.RETURN_URL
        )
        #处理返回的url参数
        callback_data = {}
        for key, value in request.GET.items():
            callback_data[key] = value
        sign = callback_data.pop('sign', None)
        self.order_sn = callback_data.get('out_trade_no', None) #订单号
        self.trade_no = callback_data.get('trade_no', None) #支付宝订单号

        # 验证签名
        self.verify = self.alipay.verify(callback_data, sign)
        return super(AlipayView, self).dispatch(request, *args, **kwargs)


    def get(self, request):
        """处理支付宝return_url返回"""

        if self.verify:
            self.deposit()
            #返回个人中心页面
            return redirect(reverse('users:detail', kwargs={
                'username': request.user.username
            }))

    def post(self, request):
        """
        处理notify_url
        """
        if self.verify:
            self.deposit()

        return Response('success')

    def deposit(self):
        """充值操作

        1.更新用户的金币信息
        2.更新订单状态为交易成功
        """

        # 数据库中查询订单记录
        order = OrderInfo.objects.get(order_sn=self.order_sn)
        order.trade_no = self.trade_no  # 支付宝订单号

        # 把人民币转换成对应的金币
        rmb = order.order_mount
        money = convert_rmb_to_money(rmb)

        # 更新用户的金币
        order.user.money += Decimal(money)
        order.user.save()
        # 订单状态置为交易成功
        order.pay_status = 'TRADE_SUCCESS'
        order.save()

当用户付款成功后，会跳转回来，那个就是return_url，处理这个的是get方法，用来更新用户的金币和订单。