dataflow/README.md

# Dataflow

A simple data transformation tool for importing, cleaning, and standardizing data from various sources.

## What It Does

Dataflow helps you:
1. **Import** CSV data with automatic deduplication
2. **Transform** data using regex rules to extract meaningful information
3. **Map** extracted values to standardized output
4. **Query** the transformed data via a web UI or REST API

Perfect for cleaning up messy data like bank transactions, product lists, or any repetitive data that needs normalization.

## Core Concepts

### 1. Sources
Define where data comes from and how to deduplicate it.

**Example:** Bank transactions deduplicated by date + amount + description

### 2. Rules
Extract information using regex patterns (`extract` or `replace` modes).

**Example:** Extract merchant name from transaction description

### 3. Mappings
Map extracted values to clean, standardized output.

**Example:** "DISCOUNT DRUG MART 32" → `{"vendor": "Discount Drug Mart", "category": "Healthcare"}`

## Architecture

- **Database:** PostgreSQL with JSONB for flexible data storage
- **API:** Node.js/Express REST API
- **UI:** React SPA served from `public/`
- **Auth:** HTTP Basic auth (configured in `.env`)

## Design Principles

- **Simple & Clear** - Easy to understand what's happening
- **Explicit** - No hidden magic or complex triggers
- **Flexible** - Handle varying data formats without schema changes

## Getting Started

### Prerequisites
- PostgreSQL 12+
- Node.js 16+
- Python 3 (for `manage.py`)

### Installation

1. Install Node dependencies:
```bash
npm install
```

2. Run the management script to configure and deploy everything:
```bash
python3 manage.py
```

For development with auto-reload:
```bash
npm run dev
```

The UI is available at `http://localhost:3000`. The API is at `http://localhost:3000/api`.

## Management Script (`manage.py`)

`manage.py` is an interactive tool for configuring, deploying, and managing the service. Run it and choose from the numbered menu:

```
python3 manage.py
```

| # | Action |
|---|--------|
| 1 | **Database configuration** — create/update `.env`, optionally create the PostgreSQL user/database, and deploy schema + functions |
| 2 | Redeploy schema only (`database/schema.sql`) — drops and recreates all tables |
| 3 | Redeploy SQL functions only (`database/queries/`) |
| 4 | Build UI (`ui/` → `public/`) |
| 5 | Set up nginx reverse proxy (HTTP or HTTPS via certbot) |
| 6 | Install systemd service unit (`dataflow.service`) |
| 7 | Start / restart `dataflow.service` |
| 8 | Stop `dataflow.service` |
| 9 | Set login credentials (`LOGIN_USER` / `LOGIN_PASSWORD_HASH` in `.env`) |

The status screen at the top of the menu shows the current state of each component (database connection, schema, UI build, service, nginx).

**Typical first-time setup:** run options 1 → 4 → 9 → 6 → 7 (→ 5 if you want nginx).

## API Reference

All `/api` routes require HTTP Basic authentication.

### Sources — `/api/sources`

| Method | Path | Description |
|--------|------|-------------|
| GET | `/api/sources` | List all sources |
| POST | `/api/sources` | Create a source |
| GET | `/api/sources/:name` | Get a source |
| PUT | `/api/sources/:name` | Update a source |
| DELETE | `/api/sources/:name` | Delete a source |
| POST | `/api/sources/suggest` | Suggest source definition from CSV upload |
| POST | `/api/sources/:name/import` | Import CSV data |
| GET | `/api/sources/:name/import-log` | View import history |
| POST | `/api/sources/:name/transform` | Apply rules and mappings to records |
| POST | `/api/sources/:name/reprocess` | Re-transform all records |
| GET | `/api/sources/:name/fields` | List all known field names |
| GET | `/api/sources/:name/stats` | Get record and mapping counts |
| POST | `/api/sources/:name/view` | Generate output view |
| GET | `/api/sources/:name/view-data` | Query output view (paginated, sortable) |

### Rules — `/api/rules`

| Method | Path | Description |
|--------|------|-------------|
| GET | `/api/rules/source/:source_name` | List rules for a source |
| POST | `/api/rules` | Create a rule |
| GET | `/api/rules/:id` | Get a rule |
| PUT | `/api/rules/:id` | Update a rule |
| DELETE | `/api/rules/:id` | Delete a rule |
| GET | `/api/rules/preview` | Preview a pattern against real records (ad-hoc) |
| GET | `/api/rules/:id/test` | Test a saved rule against real records |

### Mappings — `/api/mappings`

| Method | Path | Description |
|--------|------|-------------|
| GET | `/api/mappings/source/:source_name` | List mappings |
| POST | `/api/mappings` | Create a mapping |
| POST | `/api/mappings/bulk` | Bulk create/update mappings |
| GET | `/api/mappings/:id` | Get a mapping |
| PUT | `/api/mappings/:id` | Update a mapping |
| DELETE | `/api/mappings/:id` | Delete a mapping |
| GET | `/api/mappings/source/:source_name/unmapped` | Get values with no mapping yet |
| GET | `/api/mappings/source/:source_name/all-values` | All extracted values with counts |
| GET | `/api/mappings/source/:source_name/counts` | Record counts for existing mappings |
| GET | `/api/mappings/source/:source_name/export.tsv` | Export values as TSV |
| POST | `/api/mappings/source/:source_name/import-csv` | Import mappings from TSV |

### Records — `/api/records`

| Method | Path | Description |
|--------|------|-------------|
| GET | `/api/records/source/:source_name` | List records (paginated) |
| GET | `/api/records/:id` | Get a single record |
| POST | `/api/records/search` | Search records |
| DELETE | `/api/records/:id` | Delete a record |
| DELETE | `/api/records/source/:source_name/all` | Delete all records for a source |

## Typical Workflow

```
1. Create a source (POST /api/sources)
2. Import CSV data (POST /api/sources/:name/import)
3. Create transformation rules (POST /api/rules)
4. Preview rules against real data (GET /api/rules/preview)
5. Apply transformations (POST /api/sources/:name/transform)
6. Review unmapped values (GET /api/mappings/source/:name/unmapped)
7. Add mappings (POST /api/mappings or bulk import via TSV)
8. Reprocess to apply new mappings (POST /api/sources/:name/reprocess)
9. Query results (GET /api/sources/:name/view-data)
```

See `examples/GETTING_STARTED.md` for a complete walkthrough with curl examples.

## Project Structure

```
dataflow/
├── database/
│   ├── schema.sql         # Table definitions
│   └── functions.sql      # Import/transform/query functions
├── api/
│   ├── server.js          # Express server
│   ├── middleware/
│   │   └── auth.js        # Basic auth middleware
│   ├── lib/
│   │   └── sql.js         # SQL literal helpers
│   └── routes/
│       ├── sources.js
│       ├── rules.js
│       ├── mappings.js
│       └── records.js
├── public/                # Built React UI (served as static files)
├── examples/
│   ├── GETTING_STARTED.md
│   └── bank_transactions.csv
└── .env.example
```

## License

MIT