From 34ded08ee717a961d5d7eaf70590f415416ca4a6 Mon Sep 17 00:00:00 2001
From: eeintech <eeintech@eeinte.ch>
Date: Wed, 19 May 2021 16:17:03 -0400
Subject: [PATCH] Added InvenTreeFixerExchangeBackend class

---
 InvenTree/InvenTree/exchange.py | 44 +++++++++++++++++++++++++++++++++
 InvenTree/InvenTree/settings.py |  2 +-
 InvenTree/InvenTree/tasks.py    | 26 ++++++++-----------
 InvenTree/config_template.yaml  |  7 ++++++
 4 files changed, 62 insertions(+), 17 deletions(-)

diff --git a/InvenTree/InvenTree/exchange.py b/InvenTree/InvenTree/exchange.py
index 06de4861ec..59d2883e2a 100644
--- a/InvenTree/InvenTree/exchange.py
+++ b/InvenTree/InvenTree/exchange.py
@@ -1,4 +1,10 @@
+from django.conf import settings as inventree_settings
+
+from djmoney import settings as djmoney_settings
 from djmoney.contrib.exchange.backends.base import BaseExchangeBackend
+from djmoney.contrib.exchange.backends import FixerBackend
+
+from common.models import InvenTreeSetting
 
 
 class InvenTreeManualExchangeBackend(BaseExchangeBackend):
@@ -19,3 +25,41 @@ class InvenTreeManualExchangeBackend(BaseExchangeBackend):
         """
 
         return {}
+
+
+class InvenTreeFixerExchangeBackend(FixerBackend):
+    """
+    Backend for updating currency exchange rates using Fixer.IO API
+    """
+
+    def get_api_key(self):
+        """ Get API key from global settings """
+
+        fixer_api_key = InvenTreeSetting.get_setting('INVENTREE_FIXER_API_KEY', '').strip()
+
+        if not fixer_api_key:
+            # API key not provided
+            return None
+
+        return fixer_api_key
+
+    def __init__(self):
+        """ Override FixerBackend init to get access_key from global settings """
+
+        fixer_api_key = self.get_api_key()
+
+        super().__init__(url=djmoney_settings.FIXER_URL, access_key=fixer_api_key)
+
+    def update_rates(self):
+        """ Override update_rates method using currencies found in the settings """
+
+        currencies = ','.join(inventree_settings.CURRENCIES)
+
+        base = inventree_settings.BASE_CURRENCY
+
+        super().update_rates(base_currency=base, symbols=currencies)
+
+    def get_rates(self, **kwargs):
+        """ Returns a mapping <currency>: <rate> """
+
+        return {}
diff --git a/InvenTree/InvenTree/settings.py b/InvenTree/InvenTree/settings.py
index 5cf0b0c544..e99c3a3eea 100644
--- a/InvenTree/InvenTree/settings.py
+++ b/InvenTree/InvenTree/settings.py
@@ -515,7 +515,7 @@ CURRENCIES = CONFIG.get(
 
 BASE_CURRENCY = CONFIG.get('base_currency', 'USD')
 
-EXCHANGE_BACKEND = 'InvenTree.exchange.InvenTreeManualExchangeBackend'
+EXCHANGE_BACKEND = 'InvenTree.exchange.' + CONFIG.get('exchange_backend', 'InvenTreeManualExchangeBackend')
 
 # Extract email settings from the config file
 email_config = CONFIG.get('email', {})
diff --git a/InvenTree/InvenTree/tasks.py b/InvenTree/InvenTree/tasks.py
index b81b4e6de4..0076bb9544 100644
--- a/InvenTree/InvenTree/tasks.py
+++ b/InvenTree/InvenTree/tasks.py
@@ -163,30 +163,24 @@ def check_for_updates():
 
 def update_exchange_rates():
     """
-    If an API key for fixer.io has been provided, attempt to update currency exchange rates
+    Update backend rates
     """
 
     try:
-        import common.models
+        from .exchange import InvenTreeManualExchangeBackend, InvenTreeFixerExchangeBackend
         from django.conf import settings
-        from djmoney.contrib.exchange.backends import FixerBackend
     except AppRegistryNotReady:
         # Apps not yet loaded!
         return
+    
+    # Get backend
+    if 'InvenTreeManualExchangeBackend' in settings.EXCHANGE_BACKEND:
+        backend = InvenTreeFixerExchangeBackend()
+    else:
+        backend = InvenTreeManualExchangeBackend()
 
-    fixer_api_key = common.models.InvenTreeSetting.get_setting('INVENTREE_FIXER_API_KEY', '').strip()
-
-    if not fixer_api_key:
-        # API key not provided
-        return
-
-    backend = FixerBackend(access_key=fixer_api_key)
-
-    currencies = ','.join(settings.CURRENCIES)
-
-    base = settings.BASE_CURRENCY
-
-    backend.update_rates(base_currency=base, symbols=currencies)
+    # Update rates
+    backend.update_rates()
 
 
 def send_email(subject, body, recipients, from_email=None):
diff --git a/InvenTree/config_template.yaml b/InvenTree/config_template.yaml
index 87dfb6b545..63525b0d79 100644
--- a/InvenTree/config_template.yaml
+++ b/InvenTree/config_template.yaml
@@ -62,6 +62,13 @@ currencies:
   - JPY
   - NZD
   - USD
+# Define base currency (can also be defined in the global settings)
+# base_currency: USD
+# Define exchange backend
+# Choices are:
+# - InvenTreeManualExchangeBackend
+# - InvenTreeFixerExchangeBackend
+exchange_backend: InvenTreeFixerExchangeBackend
 
 # Email backend configuration
 # Ref: https://docs.djangoproject.com/en/dev/topics/email/