app.py

import os
from functools import wraps

from flask import Flask, Response, request, json
from rehive import Rehive, APIException

app = Flask(__name__)

# The Rehive admin API key used for the SDK.
API_TOKEN = os.environ.get('REHIVE_API_TOKEN', '')

# The webhook secret attached to the webhook in Rehive.
WEBHOOK_SECRET = os.environ.get('WEBHOOK_SECRET', '')


def get_auth_token(request, name='secret'):
    """
    Get the auth token from the AUTHORIZATION header.
    """

    try:
        auth = request.headers['HTTP_AUTHORIZATION'].split()
    except KeyError:
        return None

    if auth and auth[0].lower() != name:
        return None

    if not auth[1]:
        return None

    return auth[1]


def authenticate(request):
    """
    Return JSON indicating authorization is required.
    """

    data = {'status':'error', 
            'message': 'Invalid webhook secret.'}

    return Response(json.dumps(data), status=403, mimetype='application/json')


def requires_auth(f):
    """
    Wrapper for authentication. Checks that the correct webhook secret is 
    present in the authorization header.
    """

    @wraps(f)
    def decorated(*args, **kwargs):
        token = get_auth_token(request)
        
        if not token or token != WEBHOOK_SECRET:
            return authenticate()

        return f(*args, **kwargs)
    return decorated


@app.route('/')
def index():
    """
    Home page for the service.
    """

    return "Rehive Python Service Demo"


@app.route('/webhook/transaction/', methods=['POST'])
@requires_auth
def webhook_transaction():
    """
    Webhook endpoint. This authenticates the webhook against the stored webhook 
    secret. If the received transaction passes the validation then a savings
    account is found/created for the user and a portion of the transaction 
    amount is transfered to the savings account.
    """

    content = request.get_json(silent=True)

    source_transaction = content['data']['source_transaction']
    status = content['data']['status']
    amount = content['data']['amount']
    account_reference = content['data']['account']
    currency_code = content['data']['currency']['code']
    user_identifier = content['data']['user']['identifier'] 

    if (status == "Complete" and source_transaction is None
            and amount > 10):
        rehive = Rehive(API_TOKEN)

        accounts = rehive.admin.accounts.get(
            filters={"name": "savings", 
                     "user": user_identifier}
        )

        try:
            savings_account = accounts[0]
        except KeyError:
            savings_account = rehive.admin.accounts.create(
                name="savings",
                primary=False,
                user=user_identifier
            )

        transaction = rehive.admin.transactions.create_transfer(
            user=user_identifier,
            recipient=user_identifier,
            debit_account=account_reference,
            credit_account=savings_account['reference'],
            currency=currency_code,
            amount=int((10 * amount) / 100)
        )

    return Response(json.dumps({'status':'success'}), status=200, 
        mimetype='application/json')


# Run the falsk application
if __name__ == "__main__":
    app.run()