main.py

#!/usr/bin/env python
#
# Copyright 2007 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import webapp2
import datetime
import os
import jinja2

from google.appengine.ext import ndb

JINJA_ENVIRONMENT = jinja2.Environment(
    loader=jinja2.FileSystemLoader(os.path.dirname(__file__)),
    extensions=['jinja2.ext.autoescape'],
    autoescape=True
)

ALIAS = 'aub'

from e24PaymentPipe import Gateway

from models import Transaction

class MainHandler(webapp2.RequestHandler):
    def get(self):
        amount = self.request.GET.get('amount', 1)
        
        # The first step, after a checkout request
        # is to generate a database record.

        # Doing this gives us a unique key (automatically
        # generated by the database) that we will use
        # when requesting a payment token from KNET

        order = Transaction()
        order.total_amount = amount

        key = order.put()  # Save the unique key
       
        # Read the resource file, and generate a payment request
        file_path = os.path.join(os.path.split(__file__)[0], 'resource.cgn')
        
        pgw = Gateway(file_path, ALIAS)
        pgw.error_url = webapp2.uri_for('error', _full=True)
        pgw.response_url = webapp2.uri_for('gw', _full=True)
        pgw.amount = amount
        pgw.trackid = key.urlsafe()  # You must supply a tracking ID
                                     # which has to be unique per transaction
                                     # the Python version of the integration library
                                     # will automatically generate a key if you do not
                                     # provide one, but its best to give a value
                                     # explicity. This key is returned back as "trackid"

        
        # This line contacts KNET to get the payment token
        # and redirect URI. Any exception raised at this stage
        # should stop the application going forward.
        gw_info = pgw.get_payment_url()
        
        payment_token = gw_info['paymentID']
        payment_url = gw_info['paymentURL']


        if payment_url[-1] == '&':
            template_url = '{}PaymentID={}'
        else:
            template_url = '{}?PaymentID={}'

        order.payment_id = payment_token # Save the payment token as part of the
                                         # transaction record
        order.put()

        # Redirect the user to the payment page
        return webapp2.redirect(template_url.format(payment_url, payment_token))

class GatewayHandler(webapp2.RequestHandler):
    def post(self):


        # First step, fetch the payment id
        # and the result of the transaction,
        # use the trackid that is sent as part of
        # the initial request to get the object
        # from the database

        payment_id = self.request.POST.get('paymentid')
        result = self.request.POST.get('result')
        
        key = ndb.Key(urlsafe=self.request.POST.get('trackid'))
        order = key.get()

        error_url = webapp2.uri_for('error', _full=True, PaymentID=payment_id)
        success_url = webapp2.uri_for('success', _full=True, PaymentID=payment_id)

        
        if not order:
            # This payment id does not exist
            # return an error message
            self.response.write('REDIRECT={}'.format(error_url))
            return

        # Save the return values and status
        # and update the order

        order.result = result
        order.post_date = self.request.POST.get('postdate')
        order.transaction_id = self.request.POST.get('tranid')
        order.transaction_ref = self.request.POST.get('ref')
        order.authorization_code = self.request.POST.get('auth')

        order.put() # Update the order
        
        # Depending on the transaction status
        # we need to tell the KNET payment gateway
        # to which URL to redirect to

        if result in (u'CANCELLED', u'NOT CAPTURED'):
            self.response.write('REDIRECT={}'.format(error_url))
        
        self.response.write('REDIRECT={}'.format(success_url))

class ErrorHandler(webapp2.RequestHandler):
    def get(self):
        return self.response.write('There was an error processing you request # {}'.format(self.request.GET.get('PaymentID')))

class SuccessHandler(webapp2.RequestHandler):
    def get(self):
        pid = self.request.GET.get('PaymentID')

        # Fetch the order details
        order = Transaction.query(Transaction.payment_id==pid).get()

        # You must display the following details
        # to the customer

        context = {'total': order.total_amount,
                   'auth': order.authorization_code,
                   'postdate': order.post_date,
                   'transaction_ref': order.transaction_ref,
                   'transaction_id': order.transaction_id,
                   'tracking_id': order.key.urlsafe(),
        }

        template = JINJA_ENVIRONMENT.get_template('receipt.html')
        self.response.write(template.render(context))



app = webapp2.WSGIApplication([
    webapp2.Route('/', handler=MainHandler, name='home'),
    webapp2.Route('/gw', handler=GatewayHandler, name='gw'),
    webapp2.Route('/error', handler=ErrorHandler, name='error'),
    webapp2.Route('/thanks', handler=SuccessHandler, name='success'),
], debug=True)