It appears that not everyone knows that in python you can create classes dynamically without metaclasses. I'll show an example of how to do it.
So we've learned how to use custom QuerySet to chain requests:
Article.objects.old().public()Now we need to make it work for related objects:
user.articles.old().public()
This is done using use_for_related_fields, but it needs a little trick. Thing is that in django related managers are initialized without arguments, and our QuerySetManager takes argument - queryset class.
objects = QuerySetManager(MyQuerySet)We have to update QuerySetManager in such a way, that will allow setting queryset as class field:
class QuerySetManager(models.Manager):
use_for_related_fields = True
queryset_class = QuerySet
def get_query_set(self):
return self.queryset_class(self.model, using=self._db)
def __getattr__(self, key):
return getattr(self.get_query_set(), key)In order to use this manager, we have to create a sublcass and set queryset_class:
class MyManager(QuerySetManager):
queryset_class = MyQuerySetIt's not fun to create such class every time. So we'll write a function that does it for us:
def queryset_manager(qs_class):
class Manager(QuerySetManager):
queryset_class = qs_class
return Manager()Now it's enough to write:
objects = queryset_manager(MyQuerySet)Subscribe for the news and updates
In this article I’m going to show how to declare custom prosemirror node, how to render it with toDom method and how improve that with custom NodeView using React component.
We reviewed the best payment gateways in 2020. Here’s our comparison of their features, advantages, and disadvantages.
In this beginners friends article I'll explain how to make authentication with Google account on your Django site and how to make authentication for you REST API.
In this article we will write a small library for pulling metadata and creating a preview for a site just like Slack does.
In this article I will describe how to integrate geolocation HTML5 function to a web app so you can then easily implement it in your apps or websites. As an example we are going to create small web app which will be able to calculate the shortest route between detected user’s location and predefined destination using Google Maps API.
When we use css-sprites it's important to make browser cache them for longest period possible. On other hand, we need to refresh them when they are updated. This is especially visible when all icons are stored in single sprite. When it's outdated - entire site becomes ugly.