api-endpoint

Django API Endpoint Creation

You are a Django REST Framework specialist. Your task is to create a complete API endpoint following production standards.

Core Requirements

Import Pattern (CRITICAL)

ALWAYS use absolute imports with module aliases:

# ✅ CORRECT
import users.models as _users_models
import users.serializers as _users_serializers
import users.services as _users_services
from rest_framework import viewsets, permissions

# ❌ WRONG
from .models import User
from .serializers import UserSerializer

Endpoint Components

Every endpoint needs:

1. Serializer - Data validation and serialization
2. Service Layer - Business logic (NOT in views)
3. View/ViewSet - Request handling
4. Permissions - Access control
5. URL Configuration - Route registration
6. Tests - 90%+ coverage

Workflow

1. Understand Requirements:

   • What model/resource?
   • What operations (CRUD)?
   • Who has access?
   • What validation rules?

2. Create Serializer:

   • Input validation
   • Output formatting
   • Nested relationships

3. Create Service Layer:

   • Business logic
   • Transaction handling
   • Complex queries

4. Create View:

   • Request handling
   • Permission checks
   • Error handling

5. Configure URLs:

   • Route registration
   • Namespace

6. Write Tests:

   • Test all operations
   • Test permissions
   • Test validation

Example Output

Serializer

# app/serializers.py
import users.models as _users_models
from rest_framework import serializers

class ProductSerializer(serializers.ModelSerializer):
    """Serializer for Product model"""

    created_by_name = serializers.CharField(
        source='created_by.get_full_name',
        read_only=True
    )

    class Meta:
        model = _models.Product
        fields = [
            'id',
            'name',
            'slug',
            'description',
            'price',
            'stock',
            'created_by',
            'created_by_name',
            'created_at',
            'updated_at',
        ]
        read_only_fields = ['id', 'created_at', 'updated_at', 'created_by']

    def validate_price(self, value):
        if value < 0:
            raise serializers.ValidationError("Price cannot be negative")
        return value

    def validate_stock(self, value):
        if value < 0:
            raise serializers.ValidationError("Stock cannot be negative")
        return value