Added multicurrency convert function

INSTALL.txt

@@ -13,6 +13,10 @@ Or if you're using ``pip``::
 
     pip install django-currencies
 
+For install latest Git version use this command:
+
+    pip install -e git+git://github.com/Adys/django-currencies.git#egg=django-currencies
+
 Or if you'd prefer you can simply place the included ``currencies``
 directory somewhere on your Python path, or symlink to it from
 somewhere on your Python path; this is useful if you're working from a

README.md

@@ -3,35 +3,50 @@ Introduction
 
 django-currencies allows you to define different currencies, and includes
 template tags/filters to allow easy conversion between them.
+With In-app cache with Guacamole https://github.com/stucchio/Guacamole
+
 Usage
 
 Once you have everything set up (read the included INSTALL.txt and
 docs/), you will be able to use the following code in your templates::
 
-   {% change_currency [price] [currency_code] %}
+    {% change_currency [price] [currency_code] %}
 
    # i.e:
 
-   {% change_currency product.price "USD" %}
+    {% change_currency product.price "USD" %}
 
    # or if we have the currencies.context_processors.currencies
    # available:
 
-   {% change_currency product.price CURRENCY.code %}
+    {% change_currency product.price CURRENCY.code %}
 
 or use the filter::
 
-   {{ [price]|currency:[currency] }}
+    {{ [price]|currency:[currency] }}
 
    # i.e.:
 
-   {{ product.price|currency:"USD" }}
+    {{ product.price|currency:"USD" }}
 
 or set the CURRENCY context variable with a POST to the included view::
 
     {% url currencies_set_currency [currency] %}
 
 
+Helpers functions
+-----------------
+
+Convert multicurrency function
+
+Example of use:
+
+    from currencies.utils import convert
+    price=convert(100, "RUB", "UAH")
+
+Convert 100 Russian Rubles to Ukrainian Hryvnia (via base USD currency)
+
+
 OpenExchangeRates integration
 -----------------------------
 

currencies/models.py

@@ -1,6 +1,6 @@
 from django.db import models
 from django.utils.translation import gettext_lazy as _
-
+from guacamole import InMemoryCachingManager
 
 class Currency(models.Model):
     code = models.CharField(_('code'), max_length=3)
@@ -14,6 +14,7 @@ class Currency(models.Model):
         help_text=_('Make this the base currency against which rates are calculated.'))
     is_default = models.BooleanField(_('default'), default=False,
         help_text=_('Make this the default user currency.'))
+    objects = InMemoryCachingManager(lookup_fields=['code'])
 
     class Meta:
         ordering = ('name', )

currencies/templatetags/currency.py

@@ -1,7 +1,7 @@
 from django import template
 from django.template.defaultfilters import stringfilter
 from currencies.models import Currency
-from currencies.utils import calculate_price
+from currencies.utils import calculate_price, convert
 
 register = template.Library()
 
@@ -25,7 +25,6 @@ def render(self, context):
         except template.VariableDoesNotExist:
             return ''
 
-
 @register.tag(name='change_currency')
 def change_currency(parser, token):
     try:
@@ -34,3 +33,9 @@ def change_currency(parser, token):
         tag_name = token.contents.split()[0]
         raise template.TemplateSyntaxError('%r tag requires exactly two arguments' % (tag_name))
     return ChangeCurrencyNode(current_price, new_currency)
+
+
+@register.simple_tag(name='currency_convert')
+def my_tag(amount, from_, to_, *args, **kwargs):
+    return convert(amount, from_, to_)
+

currencies/utils.py

@@ -14,3 +14,18 @@ def calculate_price(price, currency):
     price = price * currency.factor
 
     return price.quantize(Decimal("0.01"), rounding=ROUND_UP)
+
+
+def convert(amount, from_, to):
+    if from_==to:
+      return amount
+    if amount != None:
+        amount = Decimal(amount)
+    else:
+        return None
+    amount = Decimal(amount)
+    from_currency = Currency.objects.get(code__exact=from_)
+    to_currency = Currency.objects.get(code__exact=to)
+    amount = amount * (to_currency.factor / from_currency.factor)  
+
+    return amount.quantize(Decimal("0.01"), rounding=ROUND_UP)