How I Control My Android Phone From a Cloud Server Using 100 Lines of Flask

#python #flask #termux #automation

My background scrapers run on PythonAnywhere. My phone runs Termux. I wanted the scrapers to ping my phone when something interesting happened — without Firebase, without Ngrok, without paying for anything.

So I built Intent Bus.

The Problem

Most cross-device automation forces you to choose between:

Too simple: hardcoded cron jobs with no coordination
Too complex: Redis, RabbitMQ, Firebase — full infrastructure for a simple notification

I just wanted my cloud script to say "hey, buzz my phone." That's it.

How It Works

Intent Bus is a tiny Flask app backed by SQLite. It has one job: let scripts post work, and let workers claim and execute that work.

Step 1 — Cloud script posts an intent:

curl -X POST https://your-bus.pythonanywhere.com/intent \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your_key_here" \
  -d '{"goal":"send_notification","payload":{"message":"Scrape complete"}}'

Step 2 — Termux worker claims it:

A bash script running on my phone polls the bus every 10 seconds. When it sees a job, it claims it with an atomic lock, executes it, and marks it fulfilled.

Step 3 — Phone buzzes:

termux-notification --title "System Update" --content "$MESSAGE"

That's the entire flow.

What Makes It Reliable

Three things I had to get right:

Atomic locking — SQLite's UPDATE with rowcount check ensures only one worker ever claims a job, even with multiple workers running simultaneously.

Visibility timeout — if a worker crashes mid-job, the lock expires after 60 seconds and the job goes back into the queue automatically.

Topic routing — workers only claim jobs matching their goal via ?goal=. A notification worker never accidentally picks up a logging job.

The Architecture

Cloud Scraper (PythonAnywhere)
        |
        | POST /intent
        ↓
Intent Bus (Flask + SQLite)
        |
        | claim + fulfill
        ↓
Termux Worker (Android Phone)
        |
        | termux-notification
        ↓
📱 Phone Notification

What It Can Do

Because the bus is just HTTP, any script anywhere can post or claim jobs:

Scraper finishes → notify phone
Website goes down → alert Discord
GitHub push → trigger deploy on home Raspberry Pi behind a firewall
Old Android phone → free Twilio replacement via termux-sms-send

Security

After posting this publicly, people immediately stress-tested the open endpoint. Fair. I added API key auth — key stored in PythonAnywhere's WSGI environment, never in the repo. Workers read from a local .apikey file.