Search for a command to run...
Made my first website in Microsoft Word at age 13, when I discovered the "save as html" button. Since then I've journeyed various computing languages, eventually settling for Python. I love diving into the core of my favorite framework - Django - discover and writing about new stuff.
Very good piece of work
Django offers a great deal of hidden functionality - secret gems - if you know where to look. In this serie I am showing tips and tricks to get the most out of Django.
The django-simple-history package is awesome as it shows you all the activity on a certain Django model object. It allows seeing how it was mutated over time and who changed it. However, there is one caveat: you cannot easily see what objects were de...
When working in the Django admin with a lot of users, you might sometimes want to offer the functionality to users to choose which columns they want to see in the changelist page. For some users some columns might be more relevant than to others. One...
Expiring a superuser in Django after a due date
At Wundermart we started saving monetary amounts in Django, we naively started with DecimalField(decimal_places=2) for our financial data. After some time we realized that you will lose data this way when applying calculations, for example: €100 * 0....
The django-simple-history package is awesome as it shows you all the activity on a certain Django model object. It allows seeing how it was mutated over time and who changed it. However, there is one caveat: you cannot easily see what objects were de...
Suppose you change your Django model instance, how do you know if the data actually changed? There are a few ways to achieve this, for example using django-simple-history which will add a database entry for every change to keep history.
However, you don't necessarily need to store this information in the database, as you can also copy the original data before changing the object. I've made a simple mixin that will copy the original from the database and stores it on the object itself:
class SomeModel(DiffMixin, models.Model):
some_attribute = models.IntegerField()
instance = SomeModel()
instance.some_attribute = 1
instance.save()
instance.some_attribute = 2
instance.is_changed('some_attribute')
The mixin copies the original just before saving and deleting and keeps the latest around as long as the object lives as _original .
You can expand on the mixin by for example providing more advanced comparison over all fields. When serializing the current and the original to a dictionary, dictdiffer.diff() could be a tool to establish a diff between the two.
Feel free to use and tweak my DiffMixin to your own needs: