Braintree Payments processing for Mezzanine/Cartridge

Note that this is very much a first pass and has not been thoroughly tested.

I have no intention of formally publishing this as a full PyPI package, but I'm happy for someone to take this initial code and expand it into a full package.

1. Install braintree's python client library pip install braintree

2. Add cartridge_braintree to your INSTALLED_APPS. List it higher than 'cartridge.shop', otherwise the cartridge_braintree template will not be selected.

3. Set up the following settings in your settings.py/local_settings.py

   BRAINTREE_ENV - "Sandbox" or "Production" BRAINTREE_MERCHANT - your merchant ID BRAINTREE_PUBLIC_KEY - your public key BRAINTREE_PRIVATE_KEY - your private key BRAINTREE_CLIENT_SIDE_ENCRYPTION_KEY - your client side encryption key for braintree.js

See also https://support.braintreepayments.com/customer/portal/articles/1080475-api-keys

4. Set the order form to be the modified Braintree form (in settings.py)

   SHOP_CHECKOUT_FORM_CLASS = 'cartridge_braintree.forms.BraintreeOrderForm'

This form does the following:

• Changes the shipping and billing country fields to a Select widget This ensures that the country selected can be converted to a valid code for Braintree's payment processing. The default selected country can be selected by settings.SHOP_DEFAULT_COUNTRY which is also editable in the admin.
• Changes Credit Card number and CVV to custom widgets that will generate data encrypted form inputs as required by braintree.js Note also CCV becomes a password input rather than just text.

5. Set the payment handler to be the Braintree payment handler

   SHOP_HANDLER_PAYMENT = 'cartridge_braintree.braintree_payment.payment_handler'

The templates provided with this package ensure that the credit card fields are encrypted on the client side using braintree.js. If you are overriding the templates in your own apps, then be sure to include the relevant braintreejs.html template.

See https://www.braintreepayments.com/docs/python/guide/getting_paid for Braintree's tutorial.