WePay Asynchronous Client on top of tornado

base_wepay.html

{% extends "base.html" %}
{% block page_title %} - Buy Goods {% end %}
{% block head %} <script type="text/javascript" src="https://stage.wepay.com/js/iframe.wepay.js"></script> {% end %}

{% block page_content %}
	<div id="checkout"></div>
{% end %}

{% block js %}
	WePay.iframe_checkout("checkout", "{{checkout["checkout_uri"]}}");
{% end %}

wepay.py

import tornado.httpclient
import urllib
import logging
import functools

from tornado import escape
from tornado.options import options
from tornado.httputil import url_concat

class WePayClient(object):
  def __init__(self, access_token=None, production=True):
    if access_token is not None:
      self.access_token = access_token
    else:
      self.access_token = options.wepay_access_token
    if production:
      self.host = "https://www.wepay.com/v2"
    else:
      self.host = "https://stage.wepay.com/v2"
  
  def call(self, uri, callback, params=None, access_token=None):
    if not params:
      params = {}
    headers = self._default_headers()
    if access_token or self.access_token:
      headers = self._add_auth_header(headers,(access_token if access_token else self.access_token))
    params = escape.json_encode(params)
    http = tornado.httpclient.AsyncHTTPClient()
    callback = functools.partial(self._on_wepay_request, callback)
    http.fetch(self.host+"/"+uri, method="POST", headers=headers, body=params, callback=callback)
  
  def _get_auth_url(self, redirect_uri, client_id, scope=None, params=None):
    if not scope:
      scope = "manage_accounts,collect_payments,view_balance,view_user,refund_payments,send_money"
    if not params:
      params = {}
    params['redirect_uri'] = redirect_uri
    params['scope'] = scope
    params['client_id'] = client_id
    return url_concat(self.host+ "/oauth2/authorize", params)
  
  def get_access_token(self, redirect_uri, client_id, client_secret, code, callback):
    params = {
      'redirect_uri': redirect_uri,
      'client_id': client_id,
      'client_secret': client_secret,
      'code': code,
    }
    return self.call('/oauth2/token', params=params, callback=callback)
  
  def _default_headers(self, custom={}):
    headers = {
      'Content-Type': 'application/json',
    }
    headers.update(custom)
    return headers
  
  def _add_auth_header(self,headers,access_token):
    headers['Authorization'] = 'Bearer ' + access_token
    return headers
  
  def _on_wepay_request(self, callback, response):
    if response.error:
      logging.warning("Error response %s fetching %s", response.error, response.request.url)
      callback(None)
      return
    callback(escape.json_decode(response.body))

wepayhandler.py

class WePayHandler(BaseHandler):
  @tornado.web.authenticated
  @tornado.web.asynchronous
  def get(self):
    amount = self.get_argument("amount")
    wepay = WePayClient(production=options.wepay_use_production)
    params = {
      "account_id": options.wepay_account_id,
      "amount": amount,
      "type": "GOODS",
      "short_description": "Buying ${0} worth of goods".format(amount),
      "mode": "iframe",
      "callback_uri": options.wepay_notification_url
    }
    wepay.call("checkout/create",params=params,callback=self._on_response)
   
  def _on_response(self, resp):
    self.render("base_wepay.html",checkout=resp)