# zfin-server

HTTP data service backed by [zfin](https://git.lerch.org/lobo/zfin)'s financial
data providers. Serves cached market data over HTTP for two consumers:

1. **LibreCalc spreadsheets** — trailing returns via `WEBSERVICE`/`FILTERXML`
2. **zfin CLI/TUI** — raw SRF cache files as an L1 data cache

## Quick start

```sh
# Set API keys (same as zfin)
export TWELVEDATA_API_KEY=...
export POLYGON_API_KEY=...

# Start the server
zig build run -- serve --port=8080

# In another terminal
curl http://localhost:8080/AAPL/returns
curl http://localhost:8080/AAPL/returns?fmt=xml
```

## Endpoints

| Route | Content-Type | Description |
|-------|-------------|-------------|
| `GET /` | `text/html` | Landing page |
| `GET /help` | `text/plain` | Endpoint documentation |
| `GET /symbols` | `application/json` | List of tracked symbols |
| `GET /:symbol/returns` | `application/json` | Trailing 1/3/5/10yr returns + volatility |
| `GET /:symbol/returns?fmt=xml` | `application/xml` | Same, XML for LibreCalc |
| `GET /:symbol/quote` | `application/json` | Latest quote |
| `GET /:symbol/candles` | `application/x-srf` | Raw SRF cache file |
| `GET /:symbol/dividends` | `application/x-srf` | Raw SRF cache file |
| `GET /:symbol/earnings` | `application/x-srf` | Raw SRF cache file |
| `GET /:symbol/options` | `application/x-srf` | Raw SRF cache file |

## LibreCalc usage

```
=FILTERXML(WEBSERVICE("http://localhost:8080/AAPL/returns?fmt=xml"), "//trailing1YearReturn")
```

XML response format:

```xml
<returns>
  <ticker>AAPL</ticker>
  <returnDate>2026-03-07</returnDate>
  <trailing1YearReturn>12.34000</trailing1YearReturn>
  <trailing3YearReturn>8.56000</trailing3YearReturn>
  <trailing5YearReturn>15.78000</trailing5YearReturn>
  <trailing10YearReturn>22.10000</trailing10YearReturn>
  <volatility>18.50000</volatility>
</returns>
```

## Cache refresh

Use cron to keep the cache warm for all symbols in your portfolio:

```sh
# Refresh all portfolio symbols daily at 5pm ET (after market close)
0 17 * * 1-5 cd /path/to/workdir && ZFIN_PORTFOLIO=portfolio.srf zfin-server refresh
```

The candle cache TTL is 23h45m (not a full 24h), providing a 15-minute jitter
buffer so daily cron runs at the same time always see stale data and trigger a
fresh fetch. Dividend and earnings TTLs are 14 and 30 days respectively.

The `refresh` command reads the portfolio SRF file (defaults to `portfolio.srf`
in the current directory if `ZFIN_PORTFOLIO` is not set), extracts all stock and
watch symbols, and fetches candles, dividends, and earnings for each.

## Building

Requires [Zig 0.15.2](https://ziglang.org/download/).

```sh
zig build        # build
zig build test   # run tests
zig build run -- serve --port=8080
```

## Configuration

All configuration is via environment variables:

| Variable | Required | Description |
|----------|----------|-------------|
| `TWELVEDATA_API_KEY` | Yes | TwelveData API key |
| `POLYGON_API_KEY` | No | Polygon API key |
| `FINNHUB_API_KEY` | No | Finnhub API key |
| `ALPHAVANTAGE_API_KEY` | No | Alpha Vantage API key |
| `ZFIN_PORTFOLIO` | No | Path to portfolio SRF (default: `portfolio.srf`) |
| `ZFIN_CACHE_DIR` | No | Cache directory (default: `~/.cache/zfin`) |

## License

MIT