Add currency view

LEARNER-2409

course_discovery/apps/api/v1/tests/test_views/test_currency.py

+import mock
+from django.core.cache import cache
+from django.test import override_settings
+from django.urls import reverse
+
+from course_discovery.apps.api.v1.tests.test_views.mixins import APITestCase
+from course_discovery.apps.api.v1.views.currency import CurrencyView
+from course_discovery.apps.core.tests.factories import USER_PASSWORD, UserFactory
+
+
+class CurrencyViewTests(APITestCase):
+    list_path = reverse('api:v1:currency')
+
+    def setUp(self):
+        super(CurrencyViewTests, self).setUp()
+        self.user = UserFactory(is_staff=True, is_superuser=True)
+        self.request.user = self.user
+        self.client.login(username=self.user.username, password=USER_PASSWORD)
+
+        # Clear the cache between test cases, so they don't interfere with each other.
+        cache.clear()
+
+    def test_get(self):
+        """ Verify the endpoint returns the right currency data and uses the cache. """
+        rates = {"GBP": 0.766609, "CAD": 1.222252, "CNY": 6.514431, "EUR": 0.838891}
+        currencies = {
+            'GBR': {'code': 'GBP', 'symbol': u'£'},
+            'CHN': {'code': 'CNY', 'symbol': u'¥'},
+            'CAN': {'code': 'CAD', 'symbol': '$'}
+        }
+        eurozone_countries = ['FRA']
+        get_data_return_value = [rates, currencies, eurozone_countries]
+
+        expected = {
+            "GBR": {"code": "GBP", "symbol": u"£", "rate": 0.766609},
+            "CAN": {"code": "CAD", "symbol": "$", "rate": 1.222252},
+            "CHN": {"code": "CNY", "symbol": u"¥", "rate": 6.514431},
+            "FRA": {"code": "EUR", "symbol": "€", "rate": 0.838891}
+        }
+
+        with mock.patch.object(CurrencyView, 'get_data', return_value=get_data_return_value) as mock_get_rates:
+            response = self.client.get(self.list_path)
+            self.assertDictEqual(response.data, expected)
+            self.assertEqual(mock_get_rates.call_count, 1)
+
+            # next request hits the cache
+            response = self.client.get(self.list_path)
+            self.assertEqual(mock_get_rates.call_count, 1)
+
+            # clearing the cache calls means the function gets called again
+            cache.clear()
+            response = self.client.get(self.list_path)
+            self.assertEqual(mock_get_rates.call_count, 2)
+
+    def test_no_api_key(self):
+        response = self.client.get(self.list_path)
+        self.assertEqual(response.json(), {})
+
+    @override_settings(OPENEXCHANGERATES_API_KEY='test')
+    def test_get_rates(self):
+        def mocked_requests_get(*args, **kwargs):  # pylint: disable=unused-argument
+            class MockResponse:
+                def __init__(self, json_data, status_code, text):
+                    self.json_data = json_data
+                    self.status_code = status_code
+                    self.text = text
+
+                def json(self):
+                    return self.json_data
+            return MockResponse({"bad": "data"}, 500, "baddata")
+        with mock.patch('course_discovery.apps.api.v1.views.currency.requests.get', side_effect=mocked_requests_get):
+            response = self.client.get(self.list_path)
+            response_json = response.json()
+            self.assertEqual(response_json, {})

course_discovery/apps/api/v1/urls.py

@@ -7,6 +7,7 @@ from course_discovery.apps.api.v1.views.affiliates import AffiliateWindowViewSet
 from course_discovery.apps.api.v1.views.catalogs import CatalogViewSet
 from course_discovery.apps.api.v1.views.course_runs import CourseRunViewSet
 from course_discovery.apps.api.v1.views.courses import CourseViewSet
+from course_discovery.apps.api.v1.views.currency import CurrencyView
 from course_discovery.apps.api.v1.views.organizations import OrganizationViewSet
 from course_discovery.apps.api.v1.views.people import PersonViewSet
 from course_discovery.apps.api.v1.views.program_types import ProgramTypeViewSet
@@ -18,7 +19,8 @@ partners_router.register(r'affiliate_window/catalogs', AffiliateWindowViewSet, b
 
 urlpatterns = [
     url(r'^partners/', include(partners_router.urls, namespace='partners')),
-    url(r'search/typeahead', search_views.TypeaheadSearchView.as_view(), name='search-typeahead')
+    url(r'search/typeahead', search_views.TypeaheadSearchView.as_view(), name='search-typeahead'),
+    url(r'currency', CurrencyView.as_view(), name='currency')
 ]
 
 router = routers.SimpleRouter()

course_discovery/apps/api/v1/views/currency.py

+import logging
+
+import requests
+from django.conf import settings
+from rest_framework import views
+from rest_framework.permissions import IsAuthenticated
+from rest_framework.response import Response
+from rest_framework_extensions.cache.decorators import cache_response
+
+
+class CurrencyView(views.APIView):
+    permission_classes = (IsAuthenticated,)
+
+    def get_rates(self):
+        try:
+            app_id = settings.OPENEXCHANGERATES_API_KEY
+            if app_id:
+                url = 'https://openexchangerates.org/api/latest.json'
+                response = requests.get(url, params={'app_id': app_id}, timeout=2)
+                response_json = response.json()
+                result = response_json['rates']
+                return result
+            else:
+                logging.warning('No app id available for openexchangerates')
+                return {}
+        except Exception as e:  # pylint: disable=broad-except
+            response_text = '' if not isinstance(response, object) else response.text
+            message = 'Exception Type {}. Message {}. Response {}.'.format(
+                type(e).__name__, e, response_text
+            )
+            logging.error('Could not retrieve rates from openexchangerates. ' + message)
+            return {}
+
+    def get_data(self):
+        rates = self.get_rates()
+        # ISO 3166-1 alpha-3 codes
+        currencies = {
+            'IND': {'code': 'INR', 'symbol': u'₹'},
+            'BRA': {'code': 'BRL', 'symbol': 'R$'},
+            'MEX': {'code': 'MXN', 'symbol': '$'},
+            'GBR': {'code': 'GBP', 'symbol': u'£'},
+            'AUS': {'code': 'AUD', 'symbol': '$'},
+            'CHN': {'code': 'CNY', 'symbol': u'¥'},
+            'COL': {'code': 'COP', 'symbol': '$'},
+            'PER': {'code': 'PEN', 'symbol': 'S/.'},
+            'CAN': {'code': 'CAD', 'symbol': '$'}
+        }
+        eurozone_countries = [
+            'AUT', 'BEL', 'CYP', 'EST', 'FIN', 'FRA', 'DEU', 'GRC', 'IRL',
+            'ITA', 'LVA', 'LTU', 'LUX', 'MLT', 'NLD', 'PRT', 'SVK', 'SVN', 'ESP'
+        ]
+        return [rates, currencies, eurozone_countries]
+
+    # Cache exchange rates for 1 day
+    @cache_response(60 * 60 * 24)
+    def get(self, request, *args, **kwargs):
+        rates, currencies, eurozone_countries = self.get_data()
+        if not rates:
+            return Response({})
+
+        for country, currency in currencies.items():
+            currency_name = currency['code']
+            currencies[country]['rate'] = rates.get(currency_name)
+
+        eurozone_data = {'code': 'EUR', 'symbol': '€', 'rate': rates.get('EUR')}
+        for country in eurozone_countries:
+            currencies[country] = eurozone_data
+
+        return Response(currencies)

course_discovery/settings/base.py

@@ -13,6 +13,8 @@ path.append(root('apps'))
 # SECURITY WARNING: keep the secret key used in production secret!
 SECRET_KEY = os.environ.get('COURSE_DISCOVERY_SECRET_KEY', 'insecure-secret-key')
 
+OPENEXCHANGERATES_API_KEY = None
+
 # SECURITY WARNING: don't run with debug turned on in production!
 DEBUG = False