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)