# WP-51 — OpenZaak Documenten (DRC) upload + link

Status: done (5807937)
Phase: 9 — OpenZaak / ZGW integration

## Why

Uploaded documents currently persist as bytes in local SQLite (`DocumentStore`). To be
production-ready they must live in OpenZaak's **Documenten API (DRC)** as
`enkelvoudiginformatieobjecten`, linked to a Zaak via `zaakinformatieobject` — behind the same
config gate, still without a FE contract change.

## Read first

- [openzaak-integration.md](../reference/openzaak-integration.md)
- WP-49 (the seam pattern), WP-50 (create-zaak, the zaak to link to)

## Decisions (pre-made, don't relitigate)

- Introduce an `IDocumentSource` sibling of `IZaakSource`; local impl = `DocumentStore`,
  OpenZaak impl = DRC. FE upload DTOs unchanged.
- A document needs an `informatieobjecttype` **URL** from Catalogi (like zaaktype for a zaak).
- Upload → returns document URL → `zaakinformatieobject` links it to the zaak URL.

## Files

- `Data/IDocumentSource.cs`, `Data/LocalDocumentSource.cs`, `Zgw/OpenZaakDocumentSource.cs`
- `ZgwOptions`: `informatieobjecttype` URL(s) + `DrcBaseUrl`.

## Steps

1. Abstract the upload/read/link paths behind `IDocumentSource`.
2. OpenZaak impl: POST `enkelvoudiginformatieobjecten` (content), then POST `zaakinformatieobjecten`.
3. Map DRC document metadata back into the existing document DTOs.

## Acceptance criteria

- [ ] With `Zgw:Enabled=true`, an upload lands in DRC and is linked to its zaak.
- [ ] FE upload/list DTOs unchanged; no api-client drift.
- [ ] Tests cover the DRC POST bodies + the zaak-link step (stub handler).

## Verification

`dotnet test`; against a docker OpenZaak if available.

## Out of scope

Notificaties (WP-52), content virus-scanning / blob-storage tuning.

## Risks

Large file content over base64/multipart — mind memory; stream if needed.