Stripe Authorization In Open Event API Server

The Open Event System supports payments through stripe. Stripe is a suite of APIs that powers commerce for businesses of all sizes. This blogpost covers testing of Stripe Authorization Schema and endpoints in the API Server.

The Stripe Authorization class provides the following endpoints:

'/stripe-authorization'
'/stripe-authorization/<int:id>'
'/events/<int:event_id>/stripe-authorization'
'/events/<event_identifier>/stripe-authorization'


In the pull request made for adding documentation and tests, these two endpoints were removed:

'stripe_authorization_list',
'/events/<int:event_id>/stripe-authorization',
'/events/<event_identifier>/stripe-authorization'

This is because each event can have only one stripe authorization, so there can not exist a list of stripe authorization objects related to an event.

The ‘stripe_authorization_list’ endpoint is made POST only. This is because Open Event does not allow individual resources’ list to be accessible. Since, there is no endpoint which returns a list of Stripe Authorizations the StripeAuthorizationList(ResourceListis removed.

The ResourceDetail class was modified to add a query to support  results from ‘/events/<int:event_id>/stripe-authorization’ endpoint suThe view_kwargs for the detail endpoint has to contain the resource id, so event_id from view_kwags is used to get the id for stripe authorization.

stripe_authorization = self.session.query(StripeAuthorization).filter_by(event_id=view_kwargs['event_id']).one()
view_kwargs['id'] = stripe_authorization.id

Writing Test for Documentation

(Tests for the /events/1/stripe-authorization  is described here, for others please refer to links in additional references.)

To test the  /events/1/stripe-authorization endpoint for GET, we first insert a Stripe Authorization object into the database which will then be retrieved by the GET request and then compared with the expected response body from the documentation file.

Since stripe-auth has a required relationship with event class, an event must also exist for strie auth object to be created. The event is also required because the endpoint ‘events/’ expects an event object to exist. The StripeAuthorizationFactory takes care of this with event as a RelatedFactory. So when a StripeAuthorization object is inserted, an event is created first and passed as the required relationship to stripe_list_post endpoint.

The event is related to the stripe object by setting event_id = 1 in the factory.

Adding the pre-test hook for GET:

@hooks.before("StripeAuthorization > Stripe Authorization for an Event > Get Stripe Authorization Details of an Event")
def event_stripe_authorization_get_detail(transaction):
   """
   GET /events/1/stripe-authorization
   :param transaction:
   :return:
   """
   with stash['app'].app_context():
       stripe = StripeAuthorizationFactory()
       db.session.add(stripe)
       db.session.commit()


The expected response for this request can be found
 here.

Additional References:

Post Payment Charging in Open Event API Server

Order flow in Open Event API Server follows very simple process. On successfully creating a order through API server the user receives the payment-url. API server out of the box provides support for two payment gateways, stripe and paypal.
The process followed is very simple, on creating the order you will receive the payment-url. The frontend will complete the payment through that url and on completion it will hit the specific endpoint which will confirm the payment and update the order status.

Getting the payment-url

Payment Url will be sent on successfully creating the order. There are three type of payment-modes which can be provided to Order API on creating order. The three payment modes are “free”, “stripe” and “paypal”. To get the payment-url just send the payment mode as stripe or paypal.

POST Payment

After payment processing through frontend, the charges endpoint will be called so that payment verification can be done on the server end.

POST /v1/orders/<identifier>/charge

This endpoint receives the stripe token if the payment mode is stripe else no token is required to process payment for paypal.
The response will have the order details on successful verification.

Implementation

The implementation of charging is based on the custom data layer in Orga Server. The custom layer overrides the Base data layer and provide the custom implementation to “create_object” method thus, not using Alchemy layer.

def create_object(self, data, view_kwargs):
   order = Order.query.filter_by(id=view_kwargs['id']).first()
   if order.payment_mode == 'stripe':
       if data.get('stripe') is None:
           raise UnprocessableEntity({'source': ''}, "stripe token is missing")
       success, response = TicketingManager.charge_stripe_order_payment(order, data['stripe'])
       if not success:
           raise UnprocessableEntity({'source': 'stripe_token_id'}, response)

   elif order.payment_mode == 'paypal':
       success, response = TicketingManager.charge_paypal_order_payment(order)
       if not success:
           raise UnprocessableEntity({'source': ''}, response)
   return order

With the resource class as

class ChargeList(ResourceList):
   methods = ['POST', ]
   schema = ChargeSchema

   data_layer = {
       'class': ChargesLayer,
       'session': db.session
   }

Resources

  1. Paypal Payments API
    https://developer.paypal.com/docs/api/payments/
  2. Flask-json-api custom layer docs
    http://flask-rest-jsonapi.readthedocs.io/en/latest/data_layer.html#custom-data-layer
  3. Stripe Payments API
    https://stripe.com/docs/charges

Integrating Stripe in the Flask web framework

{ Repost from my personal blog @ https://blog.codezero.xyz/integrating-stripe-in-flask }

Stripe is a developer and a user-friendly payment infrastructure provider. Stripe provides easy to use SDKs in different programming languages allowing us to easily collect payments on our website or mobile application.

Flask is a web microframework for Python based on Werkzeug, Jinja 2. Flask makes building web applications in python a breeze.

Make sure you have your Flask app ready. Let’s start with installing the required dependency. The Stripe python SDK. You can get it by running.

pip install stripe

Don’t forget to add the same in your requirements.txt. (if you have one that is.)

Now, head over to Stripe: Register and create a new Stripe account to get your test keys. If you don’t wish to create an account at this time, you can use the following test keys, but you’ll not be able to see the payments in the stripe dashboard.

  • Publishable Key: pk_test_6pRNASCoBOKtIshFeQd4XMUh
  • Secret Key: sk_test_BQokikJOvBiI2HlWgH4olfQ2

We’ll need to set the secret key in the SDK.

import stripe

STRIPE_PUBLISHABLE_KEY = 'pk_test_6pRNASCoBOKtIshFeQd4XMUh'  
STRIPE_SECRET_KEY = 'sk_test_BQokikJOvBiI2HlWgH4olfQ2'

stripe.api_key = STRIPE_SECRET_KEY

Let’s create a page with a form for us to handle the Stripe payment.

<!DOCTYPE html>  
<html>  
<head>  
    <title>Pay now</title>
</head>  
<body>  
    <h4>Pay $250.00 by clicking on the button below.</h4>
    <form action="/payment" method="POST">
        <script src="https://checkout.stripe.com/checkout.js" 
                class="stripe-button"
                data-key="pk_test_6pRNASCoBOKtIshFeQd4XMUh"
                data-description="A payment for the Hello World project"
                data-name="HelloWorld.com"
                data-image="/images/logo/hw_project.png"
                data-amount="25000"></script>
    </form>
</body>  
</html>

We’re using Stripe’s Checkout library to get the payment details from the user and process. Also, keep in mind that the checkout library has to be loaded directly from https://checkout.stripe.com/checkout.js. Downloading it and serving locally will not work.

The script tag, accepts a lot of parameters. A few important ones are,

  • data-key – The Publishable Key.
  • data-amount – The amount to be charged to the user in the lowest denomination of the currency. (For example, 5 USD should be represented as 500 cents)
  • data-name – The name of your site or company that will be displayed to the user.
  • data-image – The path to an image file (maybe a logo) that you’d like to be displayed to the user.

More configuration options can be seen at Stripe: Detailed Checkout Guide.

This script would automatically create a Pay with Card button which would open the stripe Checkout lightbox when clicked by the user.

Once the payment process is completed the following parameters are submitted to the form’s action endpoint (the form inside which this script is located), along with any other elements that were in the form.

  • stripeToken – The ID of the token representing the payment details
  • stripeEmail – The email address the user entered during the Checkout process

Along with the Billing address details and Shipping address details if applicable and enabled

We’ll need to write a Flask method to handle the input that were submitted by Stripe to proceed with the transaction and charge the user.

Let’s add a new Flask route to respond when submitting the form.

@app.route('/payment', methods=['POST'])
def payment_proceed():  
    # Amount in cents
    amount = 25000

    customer = stripe.Customer.create(
        email=request.form['stripeEmail'],
        source=request.form['stripeToken']
    )

    charge = stripe.Charge.create(
        amount=amount,
        currency='usd',
        customer=customer.id,
        description='A payment for the Hello World project'
    )

    return render_template('payment_complete.html')

We’re now creating a new Stripe customer along with the stripeToken as the source parameter. The card details are stored by stripe as a token. And using this token ID, Stripe will be able to retrieve it to make the charge.

We’re creating a charge object with the amount in the lowest denomination of the currency, the currency name, the customer ID, and an optional description. This will charge the customer. On a successful transaction, a charge object would be returned. Else, an exception will be thrown.

For more information regarding the Charge object and the various other APIs available fro consumption in Stripe, checkout the Stripe API Guide.