Django & Wagtail Notes

Django MVT (Model-View-Template)

Model

• Represents the data layer of the application.
• Defines the structure of the database, including tables, fields, and relationships.
• Handles data storage, retrieval, and validation.
• Interacts with the database using Django’s ORM (Object-Relational Mapper).

Define Relationships

Many-to-Many

Should be defined on either side of the relationship using ManyToManyField(). (Notice that Category was passed as a string, because the class Category was not defined yet. Django uses a string representation and it’s considered the best practice.)

# One product can belongs to many categories, such as bread -> food & on_sale_product
# One category can also has many products, such as food -> bread & chicken
class Product(models.Model):
    name = models.CharField(max_length=50)
    categories = models.ManyToManyField('Category')

    
class Category(models.Model):
    name = models.CharField(max_length=50)

Many-to-One

Should be defined on the many side of the relationship using ForeignKey()

class Order(models.Model):
    order_number = models.CharField(max_length=50)
    customer = models.ForeignKey('Customer', on_delete=models.CASCADE)

    
class Customer(models.Model):
    name = models.CharField(max_length=50)

The kwarg: related_name

class Author(models.Model):
    name = models.CharField(max_length=50)
    
 
# Case 1
class Book(models.Model):
    title = models.CharField(max_length=200)
    author = models.ForeignKey('Author', on_delete=models.CASCADE)

author = Author.objects.all(name='Zheng Yuan')
books = author.book_set.all()  
# Default method <class_lowercase>_set

# Case 2
class Book(models.Model):
    title = models.CharField(max_length=200)
    author = models.ForeignKey('Author', 
                               related_name='books',
                               on_delete=models.CASCADE)

books = author.books.all()
# Now, the method becomes the value of related_name

One-to-One

Should be defined on either side of the relationship using OneToOneField()

View

• Acts as the business logic layer.
• Processes user requests, interacts with the Model to fetch or manipulate data, and prepares the data for rendering.
• Returns a (Django’s) HttpResponse, often by rendering a template with the processed data.
• In Django, views are typically Python functions or classes.

Template

• Represents the presentation layer.
• Defines how the data is displayed to the user.
• Uses Django’s template language to dynamically generate HTML by combining static content with data from the View.
• Separates the design (HTML/CSS) from the logic (Python code).

Miscellaneous

Abstract Class

class AbstractCorporation(models.Model):
    # id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    name = models.CharField(max_length=255, unique=True)

    class Meta:
        abstract = True

    def __str__(self):
        return self.name

• When defining abstrat = True in the subclass Meta, no table will be created in the database.

Wagtail CMS

Create Admin Menu (Group)

Create SnippetViewSet in <app_name>/views.py

from wagtail.snippets.views.snippets import SnippetViewSet, SnippetViewSetGroup
from corp_wechat.models import CorpWechat
from .models import Notificator


class CorpWechatSnippetViewSet(SnippetViewSet):
    model = CorpWechat
    form_class = CorpWechatForm
    icon = "folder-open-inverse"
    menu_label = 'CorpWechat'
    inspect_view_enabled = True


class NotificatorSnippetViewSet(SnippetViewSet):
    model = Notificator
    form_fields = ['name', 'secret', 'corp']
    icon = "folder-open-inverse"
    menu_label = 'Notificator'
    inspect_view_enabled = True


class CorpWechatSnippetViewSetGroup(SnippetViewSetGroup):
    items = (CorpWechatSnippetViewSet, NotificatorSnippetViewSet)
    icon = "crocodile"
    menu_label = "CorpWeChat"
    inspect_view_enabled = True
    add_to_admin_menu = True

Register SnippetViewSet in <app_name>/wagtail_hooks.py

from wagtail import hooks
from .views import CorpWechatSnippetViewSetGroup


@hooks.register("register_admin_viewset")
def register_viewset():
    return CorpWechatSnippetViewSetGroup()

Reference

• SnippetViewSet (Group)
• Icons