Social Network API

Production-Grade Social Graph Platform

Engineering Analysis: This project serves as a reference implementation for a production-grade social network backend. It prioritizes data integrity, reliability, and sub-millisecond read latency through the use of aggressive caching strategies, cryptographic-grade authentication, and idempotent write operations.

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Engineering Deep Dive: Core Systems

1. Idempotency and Distributed Integrity

The Challenge: In distributed systems, network partitions or client retries can lead to duplicate resource creation (e.g., posting the same comment twice). Implementation:

• Idempotency Keys: Implemented strict X-Idempotency-Key header handling.
• Atomic Locking: Uses Redis atomic operations to lock keys during processing.
• Result: Guarantees exactly-once semantics for all critical POST operations.

2. Query Optimization (N+1 Elimination)

The Challenge: Fetching social feeds (posts + author + comments + likes) often leads to the N+1 query problem, causing exponential database load. Implementation:

• Eager Loading: Extensive use of select_related and prefetch_related in Django ORM.
• Connection Pooling: Implemented database connection pooling for both PostgreSQL and Redis to handle concurrent load.
• Analysis: Reduced feed retrieval complexity from O(N) to O(1) database round-trips.

3. Security Architecture

The Challenge: Storing sensitive user data requires defense-in-depth strategies. Implementation:

• Argon2 Hashing: Password storage uses Argon2, a memory-hard function resistant to GPU/ASIC attacks.
• JWT Strategy: Stateless authentication with short-lived access tokens (15m) and sliding refresh tokens (7d).
• SSL/TLS: Full HTTPS support for local development to mirror production security constraints.

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Infrastructure Stack

Backend

Technology	Version	Engineering Purpose
Python	3.13+	Core Runtime
Django	6.0	MVT Framework
DRF	3.15+	REST Interface
PostgreSQL	18	Primary Relational Store (JSONB support)
Redis	7	Cache Layer & Message Broker
Uvicorn	Latest	ASGI Concurrency Wrappers

Frontend

Technology	Purpose
React 18	Component Library
TypeScript	Static Type Assurance
Vite	O(1) Bundling
React Query	Server State Management
Zustand	Client State Management

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Interface Specification

Authentication

Method	Endpoint	Description
POST	/api/v1/auth/register/	Register user entity
POST	/api/v1/auth/token/	Issue JWT credentials
POST	/api/v1/auth/token/refresh/	Rotate access tokens

Users Domain

Method	Endpoint	Description
GET	/api/v1/users/	Paginatable user list
GET	/api/v1/users/me/	Authenticated context
PATCH	/api/v1/users/me/	Partial profile update
GET	/api/v1/users/{username}/	Public profile view
POST	/api/v1/users/{username}/follow/	Graph connection toggle

Core Content (Posts)

Method	Endpoint	Description
GET	/api/v1/posts/	Global feed
POST	/api/v1/posts/	Create node (Idempotent)
GET	/api/v1/posts/{id}/	Node detail
PATCH	/api/v1/posts/{id}/	Node update
DELETE	/api/v1/posts/{id}/	Node removal
POST	/api/v1/posts/{id}/like/	Interaction toggle
GET	/api/v1/posts/following/	Personalized edge feed

Interactions (Comments)

Method	Endpoint	Description
GET	/api/v1/posts/{id}/comments/	Fetch child nodes
POST	/api/v1/posts/{id}/comments/	Attach child node (Idempotent)
DELETE	/api/v1/comments/{id}/	Remove child node

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Deployment & Usage

# 1. Initialization
cd social-network-api

# 2. Security Configuration (Optional)
# Generates local SSL certificates for HTTPS emulation
cd certs && bash generate-certs.sh && cd ..

# 3. Infrastructure Orchestration
docker-compose up -d

# 4. Schema Migration
docker-compose exec backend python manage.py migrate

# 5. Administrative Access
docker-compose exec backend python manage.py createsuperuser

# 6. Verification Suite
docker-compose exec backend pytest -v

Service Endpoints:

• Frontend SPA: http://localhost:3000 (or https://localhost:3000)
• API Gateway: http://localhost:8000/api/v1/
• Swagger Documentation: http://localhost:8000/api/docs/
• Admin Portal: http://localhost:8000/admin/

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Codebase Organization

social-network-api/
├── backend/
│   ├── apps/
│   │   ├── core/          # Shared utilities, abstract models
│   │   ├── users/         # Identity management & profiles
│   │   ├── posts/         # Content nodes & JSONB metadata
│   │   ├── comments/      # Interaction sub-nodes
│   │   ├── likes/         # Edge interactions
│   │   └── follows/       # Graph edges
│   ├── config/            # Environment & middleware config
│   └── requirements/      # Dependency lockfiles
├── frontend/
│   └── src/
│       ├── components/    # Atomic UI units
│       ├── pages/         # Route definitions
│       ├── hooks/         # Data fetching logic
│       ├── stores/        # Global state atoms
│       └── lib/           # Network clients
├── certs/                 # TLS artifacts
└── docker-compose.yml     # Orchestration manifest

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Quality Assurance

The project maintains a rigorous testing suite covering unit, integration, and property-based scenarios.

# Full Regression Suite
docker-compose exec backend pytest -v

# Coverage Analysis
docker-compose exec backend pytest --cov=apps --cov-report=html

# Specific Domain Testing
docker-compose exec backend pytest apps/posts/tests/ -v

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Environment Configuration

Reference .env.example for runtime parameters.

# Persistence Layer
POSTGRES_DB=social_network
DB_POOL_MIN_SIZE=2
DB_POOL_MAX_SIZE=10

# Caching & Message Broker
REDIS_URL=redis://redis:6379/0
REDIS_MAX_CONNECTIONS=50

# Security Policies
JWT_ACCESS_TOKEN_LIFETIME_MINUTES=15
JWT_REFRESH_TOKEN_LIFETIME_DAYS=7