WRNexusJS/packages/uploader/README.md

# @wrnexus/uploader

Config-driven file uploads + serving for [WrNexus](https://www.npmjs.com/org/wrnexus). Declare
named **storage stores** (local disk or any S3-compatible backend) in `wrnexus.config.ts`, upload
with one function call, drop a drag-and-drop widget on a page, and serve files back — public or
private. Zero external dependencies (S3 is signed with a built-in AWS SigV4 implementation, like the
rest of the framework).

## Usage

### Configure local and S3 stores

```ts
// wrnexus.config.ts
import type { AppConfig } from "@wrnexus/styles";

const config: AppConfig = {
  storage: {
    default: "public",
    stores: {
      // Local disk, world-readable — served by the framework with a 1-year cache.
      public: {
        driver: "local",
        dir: "uploads/public", // relative to the app root (dev) / cwd (prod)
        access: "public",
        maxBytes: 10_000_000,
        accept: ["image/*", ".pdf"], // MIME, "type/*" wildcards, or ".ext"
      },
      // Private S3 (works with AWS, Cloudflare R2, Backblaze B2, MinIO, DO Spaces).
      docs: {
        driver: "s3",
        access: "private",
        bucket: "my-bucket",
        region: "auto",
        endpoint: "https://<acct>.r2.cloudflarestorage.com",
        accessKeyId: process.env.S3_KEY!,
        secretAccessKey: process.env.S3_SECRET!,
      },
    },
  },
};
export default config;
```

### Upload from an API route or server function

```ts
// app/api/upload.ts — one-liner
import { handleUpload } from "@wrnexus/uploader";
export const POST = handleUpload({ store: "public" });
// → { ok: true, files: [{ key, url, name, type, size }] }
```

```ts
// or drive it yourself, anywhere you have the request
import { upload, getStore } from "@wrnexus/uploader";
const { files } = await upload("docs", ctx.req, { prefix: "invoices" });
await getStore("docs").driver.delete(files[0].key);
```

Uploads are validated (size + type), stored under a random, collision-proof, path-safe key
(the client filename is never used as a path), and — for public stores — returned with a servable
`url`.

### Add a client upload widget

Drop the element anywhere; the runtime (drag-and-drop, per-file progress, success/failed states) is
auto-injected on pages that contain `data-uploader`:

```html
<div
  data-uploader="public"
  data-endpoint="/api/upload"
  data-accept="image/*"
  data-max="10000000"
  data-multiple
></div>
```

Or via the first-party UI component:

```html
<div
  data-component="file-upload"
  store="public"
  endpoint="/api/upload"
  accept="image/*"
  multiple="true"
></div>
```

It dispatches bubbling events you can listen for:

- `wrnexus:upload` — `detail: { file, result: { key, url, name, size, type } }`
- `wrnexus:upload-error` — `detail: { file, error }`

### Serve private files behind application authentication

- **Public + local** → served automatically at `/__wrnexus/uploads/<store>/<key>` (immutable cache).
- **Public + S3** → `url` is the bucket/CDN URL directly.
- **Private** (any driver) → mount a route and gate it with your auth middleware:

```ts
// app/api/files/[key].ts
import { serveFromStore } from "@wrnexus/uploader";
export const GET = serveFromStore("docs"); // your middleware decides who gets in
```

## API

Uploads can participate in security and media pipelines without changing storage drivers. Pass a
`scan` hook to reject malware/DLP findings before storage, and `afterStore` to enqueue image/video
processing or indexing. If post-processing throws, WRNexus deletes the newly written object so a
partially accepted upload is never left behind.

| Export                                  | What                                                            |
| --------------------------------------- | --------------------------------------------------------------- |
| `handleUpload(opts)`                    | POST route handler → JSON `{ ok, files }`                       |
| `upload(store, req, opts)`              | Parse + validate + store; returns `{ files }`                   |
| `serveFromStore(store)`                 | Route handler that streams an object back (gate it for private) |
| `getStore(name?)` / `hasStorage(name?)` | Reach a store's `driver` (`put`/`get`/`delete`/`publicUrl`)     |
| `configureStorage(config, root)`        | Build the registry (the framework calls this at startup)        |
| `s3Driver` / `localDriver` / `signS3`   | Lower-level building blocks                                     |

## Notes

- Uploads count against the server's `maxBodyBytes`; per-file limits use each store's `maxBytes`.
- SigV4 signing is implemented from scratch (no `@aws-sdk`); tested against local S3 semantics.
  Live AWS/R2 connectivity depends on your credentials + bucket policy.
- v1 buffers each file in memory up to its size cap (fine for images/docs up to tens of MB).

## Helper and component kit

Use `formatFileSize`, `uploadAccept`, `uploadedFileMap`, `uploaderAttributes`, and `assertUploadedFiles` to keep upload forms and server validation consistent.

Enable `uploaderPlugin()` for:

- `<UploadDropzone />`
- `<UploadStatus />`

The complete blocks compose `Card`, `Alert`, and `Badge` from `@wrnexus/ui`; the specialized upload runtime remains responsible for the native file input and secure transport behavior.
Large files can use `createResumableUploadManager`. Sessions are bounded and
expiring; chunks may arrive out of order, carry SHA-256 checksums, and are
idempotent when retried. Conflicting retries reject, and the object is assembled
only after every exact-sized chunk is present.

```ts
const uploads = createResumableUploadManager({
  driver: getStore("documents").driver,
  sessions: redisUploadSessionStore,
  chunkSize: 5 * 1024 * 1024,
  maxBytes: 500 * 1024 * 1024,
  accept: ["application/pdf"],
});

const session = await uploads.create({ name: "report.pdf", size, type });
await uploads.uploadChunk(session.id, index, bytes, sha256);
```

The included memory session store is intended for one-process apps and tests.
Multi-instance production deployments should implement `ResumableSessionStore`
with shared durable storage and atomic session updates, and periodically call
`prune()` for abandoned uploads.