背景
简单介绍一下对接支付宝支付的流程。这个东西不难，但网上的资料纷繁复杂，老程序员没有耐心一步步跟着文档走，往往会跟着各种博客入坑。
1.github是最好的工具
https://github.com/alipay/alipay-sdk-python-all
做支付宝支付，和对接别的接口感觉不一样，文档很杂，博客很杂，demo也杂。直到看见这篇文档，豁然开朗。
引用一下readme.rst
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import logging
import traceback
from alipay.aop.api.AlipayClientConfig import AlipayClientConfig
from alipay.aop.api.DefaultAlipayClient import DefaultAlipayClient
from alipay.aop.api.FileItem import FileItem
from alipay.aop.api.domain.AlipayTradeAppPayModel import AlipayTradeAppPayModel
from alipay.aop.api.domain.AlipayTradePagePayModel import AlipayTradePagePayModel
from alipay.aop.api.domain.AlipayTradePayModel import AlipayTradePayModel
from alipay.aop.api.domain.GoodsDetail import GoodsDetail
from alipay.aop.api.domain.SettleDetailInfo import SettleDetailInfo
from alipay.aop.api.domain.SettleInfo import SettleInfo
from alipay.aop.api.domain.SubMerchant import SubMerchant
from alipay.aop.api.request.AlipayOfflineMaterialImageUploadRequest import AlipayOfflineMaterialImageUploadRequest
from alipay.aop.api.request.AlipayTradeAppPayRequest import AlipayTradeAppPayRequest
from alipay.aop.api.request.AlipayTradePagePayRequest import AlipayTradePagePayRequest
from alipay.aop.api.request.AlipayTradePayRequest import AlipayTradePayRequest
from alipay.aop.api.response.AlipayOfflineMaterialImageUploadResponse import AlipayOfflineMaterialImageUploadResponse
from alipay.aop.api.response.AlipayTradePayResponse import AlipayTradePayResponse
logging.basicConfig(
level=logging.INFO,
format='%(asctime)s %(levelname)s %(message)s',
filemode='a',)
logger = logging.getLogger('')
if __name__ == '__main__':
"""
设置配置，包括支付宝网关地址、app_id、应用私钥、支付宝公钥等，其他配置值可以查看AlipayClientConfig的定义。
"""
alipay_client_config = AlipayClientConfig()
alipay_client_config.server_url = 'https://openapi.alipay.com/gateway.do'
alipay_client_config.app_id = '[your app_id]'
alipay_client_config.app_private_key = '[your app private key]'
alipay_client_config.alipay_public_key = '[alipay public key]'
"""
得到客户端对象。
注意，一个alipay_client_config对象对应一个DefaultAlipayClient，定义DefaultAlipayClient对象后，alipay_client_config不得修改，如果想使用不同的配置，请定义不同的DefaultAlipayClient。
logger参数用于打印日志，不传则不打印，建议传递。
"""
client = DefaultAlipayClient(alipay_client_config=alipay_client_config, logger=logger)
"""
系统接口示例：alipay.trade.pay
"""
# 对照接口文档，构造请求对象
model = AlipayTradePayModel()
model.auth_code = "282877775259787048"
model.body = "Iphone6 16G"
goods_list = list()
goods1 = GoodsDetail()
goods1.goods_id = "apple-01"
goods1.goods_name = "ipad"
goods1.price = 10
goods1.quantity = 1
goods_list.append(goods1)
model.goods_detail = goods_list
model.operator_id = "yx_001"
model.out_trade_no = "20180510AB014"
model.product_code = "FACE_TO_FACE_PAYMENT"
model.scene = "bar_code"
model.store_id = ""
model.subject = "huabeitest"
model.timeout_express = "90m"
model.total_amount = 1
request = AlipayTradePayRequest(biz_model=model)
# 如果有auth_token、app_auth_token等其他公共参数，放在udf_params中
# udf_params = dict()
# from alipay.aop.api.constant.ParamConstants import *
# udf_params[P_APP_AUTH_TOKEN] = "xxxxxxx"
# request.udf_params = udf_params
# 执行请求，执行过程中如果发生异常，会抛出，请打印异常栈
response_content = None
try:
response_content = client.execute(request)
except Exception as e:
print(traceback.format_exc())
if not response_content:
print("failed execute")
else:
response = AlipayTradePayResponse()
# 解析响应结果
response.parse_response_content(response_content)
print(response.body)
if response.is_success():
# 如果业务成功，则通过respnse属性获取需要的值
print("get response trade_no:" + response.trade_no)
else:
# 如果业务失败，则从错误码中可以得知错误情况，具体错误码信息可以查看接口文档
print(response.code + "," + response.msg + "," + response.sub_code + "," + response.sub_msg)
"""
带文件的系统接口示例：alipay.offline.material.image.upload
"""
# 如果没有找到对应Model类，则直接使用Request类，属性在Request类中
request = AlipayOfflineMaterialImageUploadRequest()
request.image_name = "我的店"
request.image_type = "jpg"
# 设置文件参数
f = open("/Users/foo/Downloads/IMG.jpg", "rb")
request.image_content = FileItem(file_name="IMG.jpg", file_content=f.read())
f.close()
response_content = None
try:
response_content = client.execute(request)
except Exception as e:
print(traceback.format_exc())
if not response_content:
print("failed execute")
else:
response = AlipayOfflineMaterialImageUploadResponse()
response.parse_response_content(response_content)
if response.is_success():
print("get response image_url:" + response.image_url)
else:
print(response.code + "," + response.msg + "," + response.sub_code + "," + response.sub_msg)
"""
页面接口示例：alipay.trade.page.pay
"""
# 对照接口文档，构造请求对象
model = AlipayTradePagePayModel()
model.out_trade_no = "pay201805020000226"
model.total_amount = 50
model.subject = "测试"
model.body = "支付宝测试"
model.product_code = "FAST_INSTANT_TRADE_PAY"
settle_detail_info = SettleDetailInfo()
settle_detail_info.amount = 50
settle_detail_info.trans_in_type = "userId"
settle_detail_info.trans_in = "2088302300165604"
settle_detail_infos = list()
settle_detail_infos.append(settle_detail_info)
settle_info = SettleInfo()
settle_info.settle_detail_infos = settle_detail_infos
model.settle_info = settle_info
sub_merchant = SubMerchant()
sub_merchant.merchant_id = "2088301300153242"
model.sub_merchant = sub_merchant
request = AlipayTradePagePayRequest(biz_model=model)
# 得到构造的请求，如果http_method是GET，则是一个带完成请求参数的url，如果http_method是POST，则是一段HTML表单片段
response = client.page_execute(request, http_method="GET")
print("alipay.trade.page.pay response:" + response)
"""
构造唤起支付宝客户端支付时传递的请求串示例：alipay.trade.app.pay
"""
model = AlipayTradeAppPayModel()
model.timeout_express = "90m"
model.total_amount = "9.00"
model.seller_id = "2088301194649043"
model.product_code = "QUICK_MSECURITY_PAY"
model.body = "Iphone6 16G"
model.subject = "iphone"
model.out_trade_no = "201800000001201"
request = AlipayTradeAppPayRequest(biz_model=model)
response = client.sdk_execute(request)
print("alipay.trade.app.pay response:" + response)
这里唯一要注意的是当下需要哪种场景。这里不细说，笔者做的是最后一种，注意seller_id可以传空。
2.关于沙盒
笔者没用沙盒模式，据说有时会碰到莫名奇妙付款失败的情况。建议后来者直接线上干吧。
3.关于开发者社区
附下网址：
https://forum.alipay.com/mini-app/home
笔者以前很少有进入社区，并在社区提问的习惯。这次支付宝开发者社区给了我很好的体验，回复很快，大概5分钟以内，也很精准。
特别是回调环节，由于看不到错误，无法精准调试。和支付宝客服人员联调，确实方便很多。
4.注意 alipay-sdk-python的版本
这边服务器上一个旧的版本，跑起来一直出错，很难找原因。为此也折腾了好一会。笔者现在用的是(当前日期2022年6月14日)：
alipay-sdk-python 3.6.72
aliyun-python-sdk-core 2.13.35
aliyun-python-sdk-dysmsapi 2.1.1