Source: 📖 Test Driven Development with Python ch14 p 239

Creating Django ModelForms

Django comes with a built-in ModelForm class that can be used to take and validate user input to match the format of an existing model. It automatically generates HTML if you call as_p() on the form from inside the template.

from django import forms

from my_app.models import Item

class ItemForm(forms.ModelForm):
	
	class Meta:
		model = Item
		fields = ('text',)
		widgets = {
			'text': forms.fields.TextInput(attrs={
				'placehorlder': 'Enter an item',
				'class': 'form-control input-lg'
			}),
		}
		error_messages = {
			'text': {'required': "You can't have an empty list item"}
		}

Inside the ModelForm inheritance class, we define a class Meta which is responsible for storing the information about the model the form should use. The model attribute points to the model, while the fields attribute contains the fields of the chosen model that we want the form to use.

We can specify a widgets attribute to add HTML attributes to each field being used, such as placeholder text and a class name to use with Bootstrap. We can also modify the error messages raised by each field upon unsuccessful data entry. Here, we change the text field's required message to "You can't...", which will show if the user attempts to pass an empty string to the text field in the form.