Django Easy Currencies

Simple app to manage currencies conversion in Django using openexchangerates.org service.

The app will automatically invokes the service and in a single HTTP call it will creates all the necessary conversion rates permutations offline by "bypassing" the free account limitation which limits the source currency to USD using simple math alghoritms and the excellent Python's itertools utilities (so this is 100% legal!).

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Quick start

Installation

pip install django-easy-currencies

Setup

1. Add "django_easy_currencies" to your INSTALLED_APPS setting like this:

   INSTALLED_APPS = (
      ...
      'django_easy_currencies',
   )
   

2. Get an app key from openexchangerates.org (you don't need to pay, the basic free account will be enough)

3. Configure the app by providing your app id and the currencies you want to use like this:

   EASY_CURRENCIES = {
     'currencies': (
        ('USD', 'US Dollar'),
        ('EUR', 'Euro'),
        ('GBP', 'British Pound'),
        ('AUD', 'Australian Dollar'),
        ('CAD', 'Canadian Dollar'),
        ('CHF', 'Swiss Franc'),
        ('JPY', 'Japanese Yen'),
      ),
     'app_id': os.environ['EASY_CURRENCIES_APP_ID']
   } 
   

   Just a note: An environment variable holding your app id is a best practice but is not mandatory, you can define it inline in your settings.py

4. Include the "django_easy_currencies" URLconf in your project urls.py like this:

   url(r'^currency/', include('django_easy_currencies.urls')),
   

5. Add the "django_easy_currencies" context processor to your existent processors like this:

   from django.conf.global_settings import TEMPLATE_CONTEXT_PROCESSORS as BASE_CONTEXT_PROCESSORS
   
   TEMPLATE_CONTEXT_PROCESSORS = BASE_CONTEXT_PROCESSORS + (
      'django_easy_currencies.context_processors.currency',
   )
   

6. Run python manage.py migrate to create the app models.

7. Run the custom management command python manage.py currencies --update to save currency rates in your database. You should run this command at least once a day in order to have updated rates (automatization of this step is up to you)

8. (Optional) Run python manage.py currencies --list to see the loaded currency rates

Change active currency

The default currency automatically activated by the context processor is "USD". To change it "django_easy_currencies" provides a custom tag which prints a combo with all the available currencies and calls ChangeCurrencyView as soon the user select a new option. To use the tag you just need to:

1. Load the tag library:

   {% load currencies %}

2. Use the tag:

   {% currencies_combo %}

Display localized currencies in templates

1. Load the tag library:

   {% load currencies %}

2. Use the custom tag to display the converted price:

   {% local_currency original_price original_currency %}

   The tag will convert the original_price using original_currency into the current active currency (which is available in template context as "active_currency"). And formatting it with the right currency symbol.

   So, supposing you are going to print a localized book price which originally is 39.50 USD and the active currency is EUR, the result will be something like: € 31,26. And in the template it will looks like:

   {% local_currency book.price 'USD' %}

   or

   {% local_currency book.price book.original_currency %}

   It's also possible to skip number formatting by passing False as the third tag argument:

   {% local_currency book.price 'USD' False %}

   In this way the output will be simply: 31.26

If you use local_currency tag before to run currencies --update command, it will silently returns the original price without conversion.

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Converting prices in your business logic (outside of Django templates)

To convert prices programmatically you can use the CurrencyConverter class:

from django_easy_currencies.utils import CurrencyConverter

# ("EUR" is the target currency into which you wish to convert prices)
converter = CurrencyConverter('EUR') 

# (the first parameter is the price to convert, the second the original currency)
price1 = converter.convert('99.9', 'USD') 

If you use the converter before to run currencies --update command, it will raise an CurrencyConverterException.

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Credits

django-easy-currencies developed by Davide Zanotti - daveoncode.com - released under the MIT license.