README.md

Python Real-Time Clients

Real-time publisher and subscriber clients for Harper using MQTT, WebSocket, and Server-Sent Events (SSE).

Dependencies

• Python 3.7+
• paho-mqtt package (v2.0.0+) - for MQTT clients
• websockets package (v12.0+) - for WebSocket clients
• sseclient-py package (v1.8.0+) - for SSE clients
• requests package (v2.31.0+) - for SSE clients

Installation

pip install -r requirements.txt

Or install directly:

pip install paho-mqtt websockets sseclient-py requests

Usage

MQTT Clients

Publisher

./mqtt-publish.py
# or
python3 mqtt-publish.py

Subscriber

./mqtt-subscribe.py
# or
python3 mqtt-subscribe.py

WebSocket Clients

Publisher

./ws-publish.py
# or
python3 ws-publish.py

Subscriber

./ws-subscribe.py
# or
python3 ws-subscribe.py

SSE (Server-Sent Events) Client

Subscriber

./sse-subscribe.py
# or
python3 sse-subscribe.py

Note: SSE is unidirectional (server to client only), so there is no SSE publisher.

Tier Structure

All clients follow the same tier progression:

• Tier 0 (MVP): Single publish, automatic database persistence for WebSocket/SSE
• Tier 1: Database persistence enabled (MQTT: retain=True)
• Tier 2: Continuous publishing every 5 seconds

Protocol Comparison

• MQTT: Full pub/sub broker, topic-based routing, QoS levels
• WebSocket: Bidirectional, direct resource connection, lower overhead
• SSE: Unidirectional (server→client), simple HTTP-based, automatic reconnection