Add README with setup, Docker, and fail2ban instructions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -0,0 +1,152 @@
+# Nanodrop
+
+A minimal self-hosted file sharing platform. Upload a file, get a shareable link. No frills.
+
+- Server-rendered HTML, no client-side framework
+- SQLite database, files stored on disk
+- JWT authentication via httpOnly cookies
+- REST API alongside the web UI
+
+## Stack
+
+- **Runtime:** Node.js 22
+- **Framework:** Fastify
+- **Database:** SQLite (better-sqlite3)
+- **Language:** TypeScript (ESM, run directly via tsx)
+
+---
+
+## Quick start (local)
+
+```sh
+npm install
+JWT_SECRET=changeme npm run dev
+```
+
+Create a user first:
+
+```sh
+npm run register-user -- --username alice --password secret
+```
+
+Then open `http://localhost:3000`.
+
+---
+
+## Docker
+
+### Build and run
+
+```sh
+docker compose up -d
+```
+
+Requires a `.env` file (or environment variables) with at minimum:
+
+```env
+JWT_SECRET=your-secret-here
+```
+
+All data (database + uploads) is stored in the `nanodrop-data` Docker volume.
+
+### Register a user in Docker
+
+```sh
+docker compose run --rm register-user --username alice --password secret
+```
+
+### Environment variables
+
+| Variable | Default | Description |
+|---|---|---|
+| `JWT_SECRET` | *(required)* | Secret key for signing JWTs |
+| `JWT_EXPIRY` | `7d` | JWT token lifetime |
+| `PORT` | `3000` | Port to listen on |
+| `HOST` | `0.0.0.0` | Host to bind |
+| `BASE_URL` | `http://localhost:3000` | Public base URL (used in share links) |
+| `DB_PATH` | `./data/nanodrop.db` | SQLite database path |
+| `UPLOAD_DIR` | `./data/uploads` | Upload storage directory |
+| `LOG_FILE` | `./data/nanodrop.log` | Auth and access log path |
+| `MAX_FILE_SIZE` | `104857600` | Max upload size in bytes (100 MB) |
+| `COOKIE_SECURE` | `false` | Set `true` when serving over HTTPS |
+| `TRUST_PROXY` | `false` | Set `true` when behind a reverse proxy |
+
+### Reverse proxy (nginx example)
+
+When running behind nginx, set `TRUST_PROXY=true` so Nanodrop sees the real client IP in logs.
+
+```nginx
+server {
+    server_name files.example.com;
+
+    location / {
+        proxy_pass         http://127.0.0.1:3000;
+        proxy_set_header   Host              $host;
+        proxy_set_header   X-Real-IP         $remote_addr;
+        proxy_set_header   X-Forwarded-For   $proxy_add_x_forwarded_for;
+        proxy_set_header   X-Forwarded-Proto $scheme;
+        client_max_body_size 110M;
+    }
+}
+```
+
+---
+
+## Fail2ban
+
+Nanodrop logs failed login attempts to `LOG_FILE` (default `./data/nanodrop.log`) in this format:
+
+```
+[2026-03-03T12:00:00.000Z] AUTH_FAILURE ip=203.0.113.42 user-agent="curl/8.0" username="admin"
+```
+
+### 1. Create a filter
+
+`/etc/fail2ban/filter.d/nanodrop.conf`:
+
+```ini
+[Definition]
+failregex = ^.* AUTH_FAILURE ip=<HOST> .*$
+ignoreregex =
+```
+
+### 2. Create a jail
+
+`/etc/fail2ban/jail.d/nanodrop.conf`:
+
+```ini
+[nanodrop]
+enabled  = true
+filter   = nanodrop
+logpath  = /path/to/nanodrop.log
+maxretry = 5
+findtime = 60
+bantime  = 600
+```
+
+Adjust `logpath` to wherever your `LOG_FILE` is. With Docker, the log file lives inside the `nanodrop-data` volume — mount it to a host path or bind-mount a host directory instead of the named volume to make it accessible to fail2ban:
+
+```yaml
+# docker-compose.yml override
+volumes:
+  - /var/lib/nanodrop:/app/data
+```
+
+Then set `logpath = /var/lib/nanodrop/nanodrop.log`.
+
+### 3. Reload fail2ban
+
+```sh
+sudo fail2ban-client reload
+sudo fail2ban-client status nanodrop
+```
+
+---
+
+## Development
+
+```sh
+npm run dev      # start with hot reload via tsx
+npm test         # run all tests (vitest)
+npm run build    # type check (tsc --noEmit)
+```