nextpy-framework 1.1.0

A Python web framework inspired by Next.js with file-based routing, SSR, and SSG

NextPy Framework

A Python web framework inspired by Next.js. Build modern web applications with file-based routing, server-side rendering (SSR), static site generation (SSG), and more.

Features

• File-based Routing - Pages in pages/ become routes automatically
• Dynamic Routes - [slug].py creates dynamic URL segments
• Server-Side Rendering - get_server_side_props fetches data per request
• Static Site Generation - get_static_props builds pages at compile time
• API Routes - Create API endpoints in pages/api/
• HTMX Integration - SPA-like navigation without heavy JavaScript
• Jinja2 Templates - Powerful templating with layout inheritance
• Hot Reload - Instant updates on file changes during development
• Debug Panel - Built-in error overlay for development
• Components Library - Pre-built UI components (buttons, cards, forms)

Installation

Via pip

pip install nextpy-framework

Development Install (Editable)

git clone https://github.com/nextpy/nextpy-framework.git
cd nextpy-framework
pip install -e .

This installs NextPy in editable mode, so changes to the source code take effect immediately.

Quick Start

1. Create a new project

nextpy create my-app
cd my-app

2. Install dependencies

pip install -e .
# or
pip install -r requirements.txt

3. Run development server

nextpy dev

Visit http://localhost:5000 - your app starts with hot reload enabled!

4. Create a page

# pages/hello.py

def get_template():
    return "hello.html"

async def get_server_side_props(context):
    return {
        "props": {
            "message": "Hello, World!"
        }
    }

5. Create a template

<!-- templates/hello.html -->
{% extends "_base.html" %}

{% block content %}
<h1>{{ message }}</h1>
{% endblock %}

Visit http://localhost:5000/hello - page updates instantly as you edit!

Project Structure

my-app/
├── pages/                 # Your pages (file-based routing)
│   ├── index.py          # Home page (/)
│   ├── about.py          # About page (/about)
│   ├── blog/
│   │   ├── index.py      # Blog listing (/blog)
│   │   └── [slug].py     # Dynamic post (/blog/:slug)
│   └── api/
│       └── posts.py      # API route (/api/posts)
├── templates/            # Jinja2 templates
│   ├── _base.html        # Base layout
│   ├── components/       # Reusable components
│   │   ├── button.html
│   │   ├── card.html
│   │   └── form.html
│   └── index.html        # Page templates
├── public/               # Static files (CSS, JS, images)
├── main.py              # Entry point
└── requirements.txt     # Python dependencies

Package Architecture

NextPy is fully self-contained and tightly integrated:

Core Components

Module	Purpose
nextpy/server/app.py	Creates FastAPI application with routing
nextpy/core/router.py	Scans pages/, templates/, APIs dynamically
nextpy/core/renderer.py	SSR with Jinja2 + data fetching
nextpy/core/builder.py	SSG with static HTML generation
nextpy/cli.py	CLI scaffolding & commands
nextpy/components/	Button, card, form components
nextpy/middleware.py	Debug panel, error handling

Setup Files

• pyproject.toml - Package metadata & dependencies
• setup.cfg - Build configuration
• MANIFEST.in - Include non-Python files
• LICENSE - MIT License
• README.md - Documentation

How It All Works Together

1. CLI (nextpy create myapp) scaffolds project structure
2. Router scans pages/ and maps files to routes
3. Renderer executes get_server_side_props and renders with Jinja2
4. FastAPI serves pages and API routes
5. Builder generates static files for SSG
6. Watchdog detects file changes → automatic hot reload
7. Debug Middleware shows errors in development

Installable Features

✅ Works with pip install -e . for local development
✅ All files tightly integrated (no external dependencies)
✅ Auto-discovery of pages, templates, APIs
✅ CLI includes scaffolding with example structure
✅ Hot reload watches pages/, templates/, nextpy/ directories
✅ Debug panel shows errors in browser

Data Fetching

Server-Side Rendering (SSR)

Fetch data on every request:

async def get_server_side_props(context):
    # Runs on every request
    data = await fetch_from_api()
    return {"props": {"data": data}}

Static Site Generation (SSG)

Fetch data at build time:

async def get_static_props(context):
    # Runs at build time
    data = await fetch_from_api()
    return {"props": {"data": data}}

async def get_static_paths():
    # For dynamic routes - define which paths to pre-render
    return {
        "paths": [
            {"params": {"slug": "post-1"}},
            {"params": {"slug": "post-2"}},
        ]
    }

API Routes

Create API endpoints in pages/api/:

# pages/api/users.py

async def get(request):
    return {"users": [...]}

async def post(request):
    data = await request.json()
    return {"created": data}

async def put(request):
    data = await request.json()
    return {"updated": data}

async def delete(request):
    return {"deleted": True}

Components

Use pre-built components via Jinja2 macros:

{% from "components/button.html" import button %}
{% from "components/card.html" import card %}
{% from "components/form.html" import input, textarea, select %}

{{ button("Click Me", "/action", "primary") }}
{{ card(title="My Card", content="Description", link="/details") }}
{{ input("name", "Full Name", "text", "John Doe", True) }}

Layouts & Nesting

Create nested layouts with template inheritance:

<!-- templates/_base.html (root) -->
<html>
  <body>
    <nav>...</nav>
    {% block content %}{% endblock %}
  </body>
</html>

<!-- templates/_blog-layout.html (extends base) -->
{% extends "_base.html" %}
{% block content %}
  <div class="blog-container">
    {% block blog_content %}{% endblock %}
  </div>
{% endblock %}

<!-- templates/blog/[slug].html (extends blog layout) -->
{% extends "_blog-layout.html" %}
{% block blog_content %}
  <h1>{{ title }}</h1>
{% endblock %}

CLI Commands

nextpy dev      # Start development server with hot reload & debug panel
nextpy build    # Generate static files to out/
nextpy start    # Start production server
nextpy routes   # Display all registered routes
nextpy create   # Create new project

Development Features

🔥 Hot Reload - File changes trigger instant server restart
🐛 Debug Panel - Error overlay with stack traces
📍 Route Listing - View all registered routes
🎯 Auto-discovery - Pages, templates, APIs loaded automatically

Tech Stack

• FastAPI - High-performance async web framework
• Uvicorn - Lightning-fast ASGI server
• Jinja2 - Powerful templating engine with inheritance
• Pydantic - Type-safe data validation
• Watchdog - File system monitoring for hot reload
• Click - Elegant CLI framework
• HTMX - Modern browser features without JavaScript complexity
• Tailwind CSS - Utility-first CSS framework

Production Deployment

# Build static files
nextpy build

# Start production server
nextpy start

For hosting:

• Heroku: git push heroku main
• Vercel: Static hosting (use nextpy build)
• Docker: Dockerfile ready
• VPS: Run nextpy start with process manager (systemd, supervisord)

Contributing

Contributions welcome! NextPy is MIT licensed.

License

MIT