django-imagekit - better way of showing a default image? - django

Question

I'm using django-imagekit to resize my user avatars and right now to display a default avatar (if the user didn't upload his/her avatar) I do this:
views.py
try:
usr_avatar = UsrAvatar.objects.get(user=request.user.id)
except UsrAvatar.DoesNotExist:
usr_avatar = UsrAvatar.objects.get(id='0')
template.html
<img src="{{ usr_avatar.avatar_image.url }}" >
This works fine but every time a user didn't upload his/her avatar I'm hitting the database for the default avatar image.
Is there a way to eliminate hitting the database when the user doesn't have an avatar image loaded by somehow attributing the default image link to usr_avatar or just doing something in the template.html? Thank you!

Answer 1

Apt username given your question!
You could create a context processor that provides the default avatar to every template and simply make sure that the context processor caches the image
settings.py
TEMPLATE_CONTEXT_PROCESSORS = (
...
'myapp.context_processors.default_avatar',
...
)
myapp/context_processors.py
from django.core.cache import cache
def default_avatar(request):
default_avatar = cache.get('default_avatar', False)
if not default_avatar:
default_avatar = UsrAvatar.object.get(id='0')
return {
'default_avatar' : default_avatar
}
Now the template variable 'default_avatar' is available in every template:
{% if usr_avatar %}
{{ usr_avatar }}
{% else %}
{{ default_avatar }}
{% endif %}
Alternatively just use the cache in your original query:
try:
usr_avatar = UsrAvatar.objects.get(user=request.user.id)
except UsrAvatar.DoesNotExist:
usr_avatar = cache.get('default_avatar', False)
if not usr_avatar:
usr_avatar = UsrAvatar.objects.get(id='0')
But Finally, it might be even better to avoid keeping the default avatar in the database at all and instead just write a context processor like above but instead of getting the default avatar from the DB, just have a static url to the image
from django.conf import settings
def default_avatar(request):
return {
'default_avatar' : '%simages/default_avatar.jpg' % settings.STATIC_URL
}