kite/.planning/phases/04-folders-sharing-quotas-document-ux/04-04-SUMMARY.md

phase, plan, subsystem, tags, dependency_graph, tech_stack, key_files, decisions, metrics

phase	plan	subsystem	tags	dependency_graph	tech_stack	key_files	decisions	metrics
04-folders-sharing-quotas-document-ux	04	sharing-api	sharing idor audit fastapi sqlalchemy	requires provides affects 04-01 04-02 04-03 sharing-api-endpoints backend/main.py	added patterns FastAPI router with prefix /api/shares SQLAlchemy async join (Share + User for handle lookup) IntegrityError → HTTP 409 (duplicate share) IDOR protection via owner assertion → 404 (not 403)	created modified backend/api/shares.py backend/main.py	GET /received defined before DELETE /{share_id} to prevent FastAPI path parameter conflict DELETE wrong-owner returns 404 not 403 (T-04-04-02 — prevents share ID enumeration) write_audit_log uses session.flush within caller transaction (D-14 pattern) No quota table touched in shares.py — recipient quota isolation (T-04-04-04)	duration_seconds completed_date tasks_total tasks_completed files_created files_modified 145 2026-05-25 1 1 1 1

Phase 04 Plan 04: Sharing API Summary

One-liner

JWT-authenticated document sharing API with IDOR-safe revoke (404 on wrong-owner), handle-based recipient lookup, and metadata-only "received" virtual folder.

What was built

Created backend/api/shares.py implementing four endpoints:

1. POST /api/shares — grant share by recipient handle; 400 self-share, 404 bad UUID/unknown doc/unknown user, 409 duplicate (UniqueConstraint → IntegrityError)
2. GET /api/shares?document_id= — list shares owned by current user for a document, with recipient handle via JOIN
3. GET /api/shares/received — virtual "Shared with me" folder; returns metadata only (id, filename, content_type, size_bytes, created_at, owner_handle) — never extracted_text
4. DELETE /api/shares/{share_id} — revoke with IDOR protection: share.owner_id != current_user.id → 404 "Share not found"

Registered in backend/main.py as shares_router under the Phase 4 routers section.

Commits

Hash	Description
964128e	feat(phase-4): Sharing API (SHARE-01..05) — grant by handle, received folder, IDOR-safe revoke

Task Results

Task	Name	Commit	Files
1	Create backend/api/shares.py — full sharing API	964128e	backend/api/shares.py (created), backend/main.py (modified)

Verification Results

tests/test_shares.py — 7 xfailed (all stubs — implementations in 04-05)
Full suite: 1 failed (pre-existing test_extract_docx ModuleNotFoundError), 122 passed, 7 skipped, 39 xfailed

The pre-existing failure (test_extract_docx — ModuleNotFoundError: No module named 'docx') is completely unrelated to this plan (missing python-docx package in the local environment). It was already failing before this plan.

Security Invariants Verified

Threat	Mitigation	Verified
T-04-04-02: Share IDOR on DELETE	share.owner_id != current_user.id → 404	grep line 246
T-04-04-03: extracted_text leak	Not included in received response	grep: absent from return dict
T-04-04-04: Quota modification	No quotas table touched in shares.py	grep: no quotas reference
T-04-04-05: Duplicate share DoS	IntegrityError → 409 on UniqueConstraint	line 103-106
T-04-04-06: Doc existence leak	Ownership assertion → 404 (not 403)	line 99-100

Acceptance Criteria

• backend/api/shares.py exists with all four endpoint functions
• GET /api/shares/received defined before DELETE /{share_id} (line 187 vs 228)
• DELETE checks share.owner_id != current_user.id → 404
• IntegrityError → 409 for duplicate share
• write_audit_log called for share.granted and share.revoked (lines 110, 255)
• GET /received does NOT include extracted_text
• python3 -c "from api.shares import router" exits 0
• test_share_revoke_wrong_owner_404 is xfail (not FAILED)
• Full suite has zero FAILED from this plan's changes

Deviations from Plan

None — plan executed exactly as written. Route ordering, IDOR pattern, audit log calls, and quota isolation all implemented per specification.

Known Stubs

None — all four endpoints are fully implemented. Test stubs in test_shares.py are intentional xfail stubs that will be implemented in plan 04-05 (per the test file docstring).

Threat Flags

None — all trust boundaries and STRIDE threats from the plan's threat model are mitigated in the implementation.

Self-Check: PASSED

• backend/api/shares.py exists
• backend/main.py includes shares_router
• Commit 964128e exists in git log
• All 7 share tests are xfail (zero FAILED)