What are some examples of custom fields in Django?

What are some examples of custom fields in Django?

Django allows you to create custom fields by extending the models.Field class. For example, you can create a custom field for a URL that validates the input.

Can you show me how to implement a custom URL field?

Sure! You can create a custom URL field like this:

from django.db import models
from django.core.exceptions import ValidationError

class URLField(models.Field):
    def validate(self, value):
        if not is_valid_url(value):  # Implement your URL validation logic
            raise ValidationError('Invalid URL')

    # Other necessary methods here

What about a custom field for storing JSON data?

You can create a JSON field by subclassing models.TextField and using json.loads and json.dumps to handle the data. Here's a simple example:

import json
from django.db import models

class JSONField(models.TextField):
    def from_db_value(self, value, expression, connection):
        return json.loads(value) if value else {}

    def to_python(self, value):
        return json.loads(value) if isinstance(value, str) else value

    def get_prep_value(self, value):
        return json.dumps(value) if value else '{}'