Wechat Payments

Native Wechat Payments.

Native here means that Wechat mobile app must be used in order to perform a payment.

Installation

pip install git+https://github.com/vericant/wechat_pay.git@0.5#egg=wechat_pay

Usage

First of all you need to initialize an object:

from wechat_pay import WechatPay

payment = WechatPay('<app id>', '<merchant id>', '<payments key>',
                    '<notify url>', '<server ip>')

Make a prepay request

data = payment.retrieve_prepay_data('<product name>', '<transaction no>',
                                    '<price>')

It will return a dictionary with a bunch of stuff. The part that is particularly interesting here is code_url which looks something like this: weixin://wxpay/bizpayurl?pr=e42JWWu

With this code you could then generate a QR-code image:

qrencode -l H -t PNG -o qr.png 'weixin://wxpay/bizpayurl?pr=e42JWWu'

…and show it to your user in order to let her pay.

Full explanation of how this works can be found in service documentation.

Validate notification

Right after user makes a payment, Wechat server hits you back to <notify url> you specified with POST request, body of which contains useful information. Let's say you got it in the xml variable:

if payment.validate_notification(xml):
    # do something

Close order

Close the order. For following situations:

1. The payment is failed, merchant need to generate new order so close the original order to avoid duplicated payments.
2. Over the time, merchant need to close the order.

Note: The min gap time between request order and close the same order is 5 minutes.

data = payment.close_order('<transaction no>')

It will return a dictionary with a bunch of stuff if closed successfully.

The 'return_code' in dictionary describe whether it's success/fail.

The 'err_code' in dictionary describe the error code if it failed.

Full explanation of how this works and error code details can be found in service documentation.

References

• Wechat payments (Chinese)
• JSAPI implementation by @richfisher which was used originally, and this code still inherits some approaches from.

Hints

Integrations were traditionally hard to test, but not anymore. Use localtunnel and be happy.