Recoding — Exercise Platform

A controlled environment for running timed coding and writing exercises with live anti-cheat monitoring.

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What is this?

Recoding is a web platform where instructors assign exercises to participants, set time limits, and monitor activity in real time. Participants complete written or coding exercises in a browser-based editor. Every keystroke, paste, and focus loss is recorded. When time runs out, everything is saved automatically.

Instructors can create exercises, upload questions from Markdown files, assign participants, set timing, and review submissions with full typing replay.

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Who uses it?

Role	What they do
Instructor	Creates exercises, uploads questions, assigns participants, sets timing, monitors live activity, reviews submissions
Participant	Logs in, sees assigned exercises, answers questions in the editor, submits answers

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Features

• Timed exercises — start time, end time, or duration limit per exercise
• Written questions — text editor with autosave every 25 seconds
• Coding drills — Monaco editor (VS Code engine) with live Go execution via custom runner
• Question management — instructors upload .md files or add questions manually through the UI
• Live monitor — instructors see paste events, focus losses, and keystrokes in real time
• Anti-cheat — paste detection, focus-loss tracking, edit event recording, typing replay
• Audit log — every instructor action is logged with timestamp
• CSV export — download all submissions for an exercise

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Tech stack

Layer	Technology
Framework	Next.js 14 (App Router)
Database	PostgreSQL via Neon (serverless, HTTPS)
Auth	NextAuth.js (credentials + JWT)
Editor	Monaco Editor
Code runner	Custom Go service (jvcByte/code-runner)
Deployment	Vercel (app) + Render (runner) + Neon (database)

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Getting started

1. Clone with submodules

git clone --recurse-submodules https://github.com/jvcByte/recoding.git
cd recoding
npm install

2. Configure environment

cp .env.example .env.local

Fill in .env.local:

DATABASE_URL=postgresql://user:password@host-pooler.region.neon.tech/dbname?sslmode=require
NEXTAUTH_SECRET=<openssl rand -base64 32>
NEXTAUTH_URL=http://localhost:3000
RUNNER_URL=https://your-runner.onrender.com
RUNNER_API_KEY=<openssl rand -base64 32>

3. Set up the database

npm run migrate          # create all tables
npm run seed             # seed exercises and default users
npm run import-questions # import questions from docs/ into DB

Default accounts created by seed:

• instructor / instructor123
• participant / participant123

4. Start the dev server

npm run dev

Open http://localhost:3000.

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Code runner

Coding drills require the code-runner service — a lightweight Go HTTP server that compiles and runs participant code.

It's included as a git submodule at runner/. Deploy it to Render (free tier):

1. Go to render.com → New → Web Service
2. Connect github.com/jvcByte/code-runner
3. Runtime: Docker
4. Add env var: RUNNER_API_KEY=<same secret as in main app>
5. Deploy, then set RUNNER_URL=https://your-service.onrender.com in the main app

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Available scripts

Command	Description
npm run dev	Start development server
npm run build	Build for production
npm run migrate	Apply pending database migrations
npm run migrate:fresh	Drop all tables, re-run migrations, seed, import questions
npm run seed	Seed exercises and default users
npm run import-questions	Import questions from docs/ into the database
npm run cleanup	Delete autosave history older than 30 days
npm run reset-password <username> <password>	Reset a user's password

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Project structure

app/
  api/           — API route handlers
  instructor/    — Instructor dashboard pages
  participant/   — Participant session pages
  components/    — Shared UI components (Navbar, LogoutButton)
docs/
  ascii-art/     — ASCII art coding drills (11 questions)
  ascii-art-web/ — ASCII art web coding drills (12 questions)
  go-reloaded/   — Go-reloaded written questions (15 questions)
  prompt-piscine/— Prompt engineering written questions
  banner_files/  — standard.txt, shadow.txt, thinkertoy.txt (injected as stdin)
lib/
  auth.ts        — NextAuth configuration
  db.ts          — Neon serverless database client
  flagging.ts    — Anti-cheat flag evaluation
  questions.ts   — Exercise content loader (reads from DB, falls back to docs/)
  audit.ts       — Audit log helper
  rateLimit.ts   — Login rate limiter
  utils.ts       — Shared utility functions (interval parsing, slug conversion, markdown parsing)
migrations/      — SQL migration files (versioned, tracked in schema_migrations table)
runner/          — Go code runner (git submodule → jvcByte/code-runner)
scripts/         — CLI utilities (migrate, seed, import-questions, cleanup, reset-password)

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Exercises

Slug	Type	Questions	Description
ascii-art	Code (Go)	11	Build an ASCII art renderer from scratch
ascii-art-web	Code (Go)	12	Serve ASCII art over HTTP
go-reloaded	Written	15	Reflect on building a text transformation tool
prompt-basics	Written	12	Prompt engineering fundamentals
prompt-patterns	Written	12	Advanced prompting patterns
ai-ethics	Written	12	AI ethics scenarios
debug-control	Written	12	Debugging mindset
ethical-ai	Written	12	Ethical AI in practice
reasoning-flow	Written	15	Reasoning and flow
role-prompt	Written	15	Role-based prompting
tool-prompts	Written	15	Tool-use prompting

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Production checklist

Before going live:

• Rotate NEXTAUTH_SECRET (was in git history)
• Rotate Neon database password
• Set RUNNER_API_KEY on both Render and Vercel
• Run npm run migrate on production DB
• Run npm run import-questions to populate questions
• Set up autosave cleanup cron: 0 2 * * * npm run cleanup
• Add Strict-Transport-Security header for HTTPS enforcement

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License

MIT