In my recent project there was a lot of data business logic, so I had to organize this code somehow. In this article I'll describe a few hints on how to it.
Mixins
Simple business logic functions should in models or managers. When there's a lot of them, the can be split in mixins.
# logic.py
class EventLogic(object):
def start(self):
if self.condition():
# ...
# models.py
class Event(models.Model, EventLogic):
name = models.CharField()
# ...Custom exceptions
For business logic errors you should declare custom exception classes. It's not fun to understand what this specific IntegrityError means.
Generic views
When all logic is in model and can throw, say, BusinessLogicException, we can write views like this:
from django.contrib import messages
def event_action(requets, event_id, action):
# event = get_object_or_404(...)
try:
getattr(event, action)(request.user)
except BusinessLogicException, e:
messages.warning(request, e.message)
return redirect(request.POST.get('next') or event)Subscribe for the news and updates
This quick introduction to TDD is meant to show the implementation of this practice with a real-life example.
We’ll tell you how to create a video timelapse from a sequence of snapshots and provide customers with video playlists optimized for browser playback.
In one of our recent projects, we had an interesting case: the whole application was built around an interactive map for a fairly large shopping mall, and the main goal of the system was to plot the closest route to a user-selected destination.
In our article, you will find the best JavaScript framework comparison so that you know for sure how to choose the right one for your project.
File upload works differently from simple form inputs, which can be somewhat troublesome for beginners. Here I'll show you how to handle uploads with ease.
Everybody knows about permalink, but it's usually used only in get_absolute_url. I prefer to use it for all related model urls.class Event(models.Model):# ...@models.permalinkdef edit_url(self):return ('event_edit', (self.pk, ))And then in template:<a href="{{ event.edit_url }}">Редактировать событие</a>