This simple application provides stats and aggregation capabilities for the Django admin changelist view.

It allows to display stats at the end of the changelist page in a easy way, just adding one option to the model admin object.

Installation

The Mercurial repository of the application can be cloned with this command:

hg clone https://bitbucket.org/frankban/django-admin-changelist-stats

The admin_stats package, included in the distribution, should be placed on the PYTHONPATH.

Otherwise you can just pip install django-admin-changelist-stats.

Settings

Add the request context processor in your settings.py, e.g.:

from django.conf.global_settings import TEMPLATE_CONTEXT_PROCESSORS
TEMPLATE_CONTEXT_PROCESSORS += (
     'django.core.context_processors.request',
)

Add 'admin_stats' to the INSTALLED_APPS in your settings.py.

Quickstart

Assume you have a Vote model with a score integer field. The related model admin would look like this:

from django.contrib import admin

from myproject.vote import models

class VoteAdmin(admin.ModelAdmin):
    list_display = ('__unicode__',)

admin.site.register(models.Vote, VoteAdmin)

It is straightforward to display simple aggregation stats at the end of the changelist page. For instance, if you want to display the average score and the sum of all scores, referred to the votes currently present in the view, you can just write:

from admin_stats.admin import StatsAdmin, Avg, Sum

class VoteAdmin(StatsAdmin):
    list_display = ('__unicode__',)
    stats = (Avg('score'), Sum('score'))

Note that now the model admin is a subclass of StatsAdmin.

Builtin stats

The application provides the following aggregation stats:

• Avg: the average of values over the results
• Sum: the total sum of values
• Min: the min value over the queryset
• Max: the max value

Each one takes the related field as arguments, as seen in the example above. To avoid too many db queries, the aggregation is done using a single queryset.aggregate call, but, if you want, you can hit the database all the times you want using the alone kwarg, e.g.:

stats = (Avg('score'), Sum('score'), Min('score', alone=True))

Custom stats

The stats admin option takes a sequence of callables, and obviously you can write your own. A stats callable takes 3 arguments:

• the current request
• the current objects displayed in the changelist page
• a dict object data (the result of all collected aggregations)

and must return a sequence (label, value) where the label is a short description of the value returned, e.g.:

def answer(request, objects, data):
    return 'The Answer', 42

class VoteAdmin(StatsAdmin):
    stats = [answer]

The value returned by custom stats is considered safe, so it can be an html string too.

Template filters

This application provides a set of aggrgation template filters too:

• avg_of
• sum_of
• min_of
• max_of
• count_of

Each one is used over a queryset and return the aggregation of the given field, e.g.:

{% load admin_stats_tags %}
{{ myqueriset|avg_of:'field' }}

or:

{% load admin_stats_tags %}
{% with objects|sum_of:'hours' as total_hours %}
    Total hours: {{ total_hours }}
{% endwith %}