# OpenSpec Change: enterprise-server-caddy-imgproxy

- **Change ID**: enterprise-server-caddy-imgproxy
- **Package**: `@suaveplan/caddy-imgproxy`
- **Category**: server/infra
- **Target path**: `server/infra/caddy-imgproxy`
- **Status**: PROPOSED
- **Date**: 2026-04-24
- **Reference spec**: `/mnt/s/web/suaveplan/enterprise/caddy-imgproxy.md`

---

## Summary

Deliver `@suaveplan/caddy-imgproxy` on the genesis branch from scratch at enterprise quality. The package provides a typed TypeScript client and URL-builder for [imgproxy](https://imgproxy.net/) behind a Caddy reverse proxy. It generates HMAC-SHA256 signed imgproxy URLs for resize, crop, format conversion, quality, watermark, blur, and brightness operations. It does not spawn processes — it is a pure URL-generation and request-signing library with injectable `@suaveplan/crypto` for signing and Zod-validated option schemas.

---

## Current-state audit (genesis)

Does not exist on genesis — fresh build.

---

## Available workspace deps on genesis

| Package | Role |
|---|---|
| `@suaveplan/error` (`workspace:^`) | Typed `IMGPROXY.*` error codes |
| `@suaveplan/types` (`workspace:^`) | `LoggerLike` |
| `@suaveplan/crypto` (`workspace:^`) | HMAC-SHA256 signing |
| `zod` (`catalog:forms`) | Options validation |
| `@opentelemetry/api` (`catalog:observability`) | Counters |
| `tslib` (`catalog:build`) | Runtime helpers |

---

## Public API surface

```ts
class ImgproxyUrlBuilder {
  constructor(options: ImgproxyOptions)
  build(options: ImgproxyTransformOptions): string
  buildSigned(options: ImgproxyTransformOptions): string
}

function createImgproxyUrlBuilder(options: ImgproxyOptions): ImgproxyUrlBuilder

interface ImgproxyOptions {
  baseUrl: string
  key?: string        // hex-encoded signing key
  salt?: string       // hex-encoded salt
  defaultQuality?: number
}

interface ImgproxyTransformOptions {
  src: string         // source image URL or S3 path
  width?: number
  height?: number
  resizingType?: 'fit' | 'fill' | 'crop' | 'pad' | 'auto'
  format?: 'webp' | 'avif' | 'jpeg' | 'png' | 'gif' | 'ico' | 'svg'
  quality?: number
  blur?: number
  brightness?: number
  contrast?: number
  gravity?: 'sm' | 'ce' | 'no' | 'so' | 'ea' | 'we' | 'noea' | 'nowe' | 'soea' | 'sowe' | 'fp'
  watermark?: WatermarkOptions
  dpr?: number
  enlarge?: boolean
  extend?: boolean
}

interface WatermarkOptions {
  opacity: number
  position?: string
  xOffset?: number
  yOffset?: number
  scale?: number
}

const ImgproxyOptionsSchema: z.ZodSchema<ImgproxyOptions>
const ImgproxyTransformOptionsSchema: z.ZodSchema<ImgproxyTransformOptions>

type ImgproxyErrorCode =
  | 'IMGPROXY_INVALID_OPTIONS'
  | 'IMGPROXY_SIGN_FAILED'
  | 'IMGPROXY_INVALID_SOURCE_URL'

function registerImgproxyErrorCodes(): void
```

---

## File layout

```text
server/infra/caddy-imgproxy/
  package.json
  tsconfig.json
  vitest.config.ts
  src/
    index.ts
    error-codes.ts
    constants/index.ts
    types/
      imgproxy.types.ts
      imgproxy.types.md
    builder/
      imgproxy-url-builder/
        imgproxy-url-builder.ts
        imgproxy-url-builder.md
        imgproxy-url-builder.types.ts
        imgproxy-url-builder.test.ts
        index.ts
    utils/
      path-encoder.ts
      path-encoder.md
      path-encoder.test.ts
  tests/
    integration.test.ts
```

---

## Impact

Downstream: any package needing image transformation URLs (file upload API, media service, CDN pipeline). Pure URL generation — no network required.

**Prerequisites on Verdaccio**: `@suaveplan/error`, `@suaveplan/types`, `@suaveplan/crypto`.