[blocked until 9+] Enable Request-a-Copy without conflicting with the confirm-license flow

[kosarko]

Goal

Surface DSpace's Request-a-Copy (request.item.type) for genuinely access-restricted files, without showing it on files that are merely awaiting license confirmation.

Background / why it's off today

Request-a-Copy never appears for two reasons:

1. The inline link-rewrite in FileDownloadLinkComponent.getBitstreamPath() is commented out (since the 7.5 upgrade, commit eef127f).
2. The item page render path (clarin-files-section → preview-section → file-description) bypasses ds-file-download-link entirely, so no canDownload/canRequestACopy is ever evaluated there.

Do not re-enable the upstream inline component. On a file with an unsigned license, canDownload=false and canRequestACopy=true (because RequestCopyFeature = !authorizeActionBoolean(READ), and the license exception makes READ false). Re-enabling the upstream if
(!canDownload && canRequestACopy) redirect would therefore render a spurious "Request a copy" button on every license-pending file — the exact conflict we want to avoid.

Where the button goes (and why this is conflict-free)

Put the request button on ClarinBitstreamAuthorizationDeniedComponent — the page that renders clarin.bitstream.authorization.denied.message ("Access to download the … file was denied by the bitstream resource policy").

This is safe by construction, not by luck:

• Backend AuthorizeServiceImpl.authorizeAction() throws "Authorization denied…" for a resource-policy failure before the license check (authorizeBitstream) ever runs.
• The FE processClarinAuthorization() forks the two failures onto different pages: MISSING_LICENSE_AGREEMENT_EXCEPTION → license-agreement page; AUTHORIZATION_DENIED_EXCEPTION → this denied page.

So a license problem can never land on the denied page. Gate the button on being on this page (the exception), never on canRequestACopy alone — the latter is true on license pages too and would reintroduce the conflict.

Implementation notes for the button:

• The denied component only has bitstream$; the request-a-copy route is /items/{itemUuid}/request-a-copy?bitstream={uuid}, so resolve bitstream → parent item first.
• The target BitstreamRequestACopyPageComponent re-checks auth and bounces to /forbidden if its check fails — confirm canRequestACopy=true before linking.
• With request.item.type=logged, anonymous users on the denied page get canRequestACopy=false (no button) — decide whether to prompt login instead of leaving a dead end.

What's expected of the license on the item

• Restricted files that should offer Request-a-Copy: have no READ resource policy and no license mapping. These fail authorize(READ) first → denied page → button. This is the only population the feature targets.
• Files with a license: must carry a READ policy + a license mapping; they route to the license page, never the denied page.
• To make a license transparent (behave like upstream, no extra gate), attach a license whose confirmation is NOT_REQUIRED — getLicenseToAgree returns null, so READ collapses to pure resource-policy. Use this for items that should behave exactly like stock DSpace.

Configuration

• request.item.type = logged (or all) — blank disables the feature.
• requestitem.xml — author/grantor extraction strategy (already configured).
• request.item.reject.email (default true) — whether rejections email the requester.

Grant-side delivery — TBD, blocked on DSpace 9

On approval, the current backend (RequestItemEmailNotifier.sendResponse) emails the raw file bytes as attachments — no link fallback, no size cap. This breaks for large datasets.

The clean fix (secure time-limited download link) is DSpace 9.0 only (issues DSpace/DSpace#10265/DSpace/DSpace#10407, FE DSpace#3984, DSpace/RestContract#307). It is not back-portable cheaply, and the existing dtoken (in our fork) cannot be reused as a substitute: the dtoken is welded to
license_resource_mapping at mint, storage, and verification (findByTokenAndBitstreamId keys on clrua.licenseResourceMapping.bitstream.id), so it can't be issued for a no-mapping file.

References

• FE: file-download-link.component.ts, clarin-bitstream-download-page.component.ts (processClarinAuthorization), clarin-bitstream-authorization-denied/, bitstream-request-a-copy-page.component.ts
• BE: AuthorizeServiceImpl.authorizeAction (line ~174 vs ~186), AuthorizationBitstreamUtils, ClarinUserMetadataRestController (token mint, line ~219), ClarinLicenseResourceUserAllowanceDAOImpl.findByTokenAndBitstreamId, RequestItemEmailNotifier.sendResponse
• Upstream: Request-a-copy improvement: Allow access via secure URL / access token for configurable duration DSpace/DSpace#10265/Request-a-copy improvements: Support access via secure links DSpace/DSpace#10407, FE Request-a-copy improvements: Support access by secure link DSpace/dspace-angular#3984, Request-a-copy: ALTCHA challenge endpoint doc DSpace/RestContract#307 (all milestone 9.0)