Stario Deep Dive: Building Real-time Python Apps
A complete walkthrough of Stario, a Python web framework for real-time applications. We build a multiplayer tile game and explain every concept along the way.
This is a deep dive into how Stario thinks about web development: explicit configuration, handler signatures, streaming responses, and Datastar integration.
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⏱️ Timestamps
0:00 Introduction & Demo
2:00 Project Structure
4:00 Tracers (RichTracer vs JsonTracer)
8:30 The Stario Application
10:00 Static Assets & Fingerprinting
12:30 Route Registration
14:00 Handler Signature (Context, Writer)
16:30 Context Object Deep Dive
23:00 Writer Object Deep Dive
31:30 The w.alive Pattern
43:00 The Click Handler & Background Tasks
50:00 HTML Generation
58:00 Datastar Integration (data.* and at.*)
1:05:00 Summary & Wrap Up
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🔑 Key Concepts
*Handler Signature*
Every handler: async def handler(c: Context, w: Writer) - None
Context: request data, signals, tracing, state
Writer: send responses, stream updates, manage connection
*Three Handler Patterns*
1. Quick response: w.html() - send and done
2. Streaming: w.alive() loop with w.patch()
3. Background: w.empty() then continue processing
*Writer Methods*
w.html(element) - full HTML response
w.patch(element) - SSE DOM update
w.empty(204) - close connection, continue handler
w.alive(iterator) - loop until disconnect
*Datastar Integration*
data.signals() - reactive state
data.on() - event handlers
data.init() - on load actions
at.get(), at.post() - server actions
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🔗 Links
Stario: https://github.com/starfederation/stario
Docs: https://stario.dev
Datastar: https://data-star.dev
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🚀 Try it yourself
pip install stario
stario init tiles --template tiles
cd tiles
uv run main.py
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📚 Covered in this video
Project setup and configuration
RichTracer for development, JsonTracer for production
Static assets with automatic fingerprinting
Handler lifecycle and the Writer pattern
Long-lived SSE connections with w.alive
Background task pattern (no separate concept needed)
HTML generation with stario.html
Datastar attributes and actions
Relay pub/sub for real-time updates
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