Django Foo hosting now in Russian

We are pleased to anounce that our hosting platform is now available in Russian.
Many thanks to Viktor “Barbuza” Kotseruba who helped with the translation.

Display Django Version

Ever wondered how to detect which version of Django you are actually running?
Well it is as simple as this:

>>> import django
>>> django.VERSION
(1, 2, 1, 'final', 0)
>>> django.get_version()
u'1.2.1 SVN-13348'
>>>

Use javascript, css in admin

Ever wanted to use your own JavaScript OR CSS inside the built in Django admin?
Well… it is possible!

All you need to do is the following:
1) Add a admin.py (if you don’t already have yet…) for your app

from django.db import models
from django.contrib import admin

from myapp.hotels.models import Hotel

class HotelAdmin(admin.ModelAdmin):
    ...
    class Media:
        js = ("/media/javascript/yourjs.js",)

admin.site.register(Hotel, HotelAdmin)

2) Create a file yourjs.js under /media/javascript

(function($) {
    $(document).ready(function($) {
         // you can now use jquery / javascript here...
         alert('It worked.');
    });
})(django.jQuery);

3) Open the admin for your application and you should see the ‘It worked’ message.

AVG Decimal simplejson (Decimal is not JSON serializable)

If you use AVG aggregation function on Integer field in MySQL,

hotels = Hotel.objects.filter(city = "Paris").extra(
    select={
        'avg_rate': 'SELECT AVG(hotel_review.rate) FROM hotel_review WHERE hotel_review.is_active = 1 AND hotel_review.hotel_id = hotel_hotel.id',
    },
)

you will have in a result { “avg_rate” : Decimal(’2.6667′)} and an “Exception Value: Decimal(’2.6667′) is not JSON serializable”.
In this case you can do this:

from django.utils import simplejson
from decimal import Decimal

class MyJSONEncoder(simplejson.JSONEncoder):
    """JSON encoder which understands decimals."""

    def default(self, obj):
        '''Convert object to JSON encodable type.'''
        if isinstance(obj, Decimal):
            return "%d" % obj
        return simplejson.JSONEncoder.default(self, obj)

hotels_json = simplejson.dumps(list(hotels.values()), cls = MyJSONEncoder)

You can read about extra search fields and JSON serialization in our article

Increment/Decrement Field value

Incrementing or decrementing field values can be done by using the F() function.
UPDATE FIELD = FIELD + 1 WHERE… ?

from django.db.models import F

# views.py ...
offer = Offer.objects.get(...)
# SQL: UPDATE field_to_increment = field_to_increment + 1 ...
offer.field_to_increment = F('field_to_increment') + 1
offer.save()