feat: partage dirigé entre utilisateurs #196

- create_share/shared_with + validation des destinataires
- gate auth sur /s/{token} (+pdf, raw) : 404 opaque hors créateur/admin/destinataires
- GET /api/shares scopé (non-admin = créés + reçus), révocation créateur/admin
- UI : dialogue dirigé/public + destinataires, dashboard « partagé par X »
- i18n FR/EN, tests test_directed_shares.py (9), fiche feature

backend/routers/sharing.py

@@ -24,7 +24,8 @@ import frontmatter
 from fastapi import APIRouter, Body, Depends, HTTPException, Query, Request
 from fastapi.responses import FileResponse, HTMLResponse, Response
 
-from backend.auth.middleware import check_vault_access, require_auth
+from backend.auth.middleware import check_vault_access, get_current_user, require_auth
+from backend.auth.user_store import get_user
 from backend.indexer import get_vault_data, parse_markdown_file, update_single_file
 from backend.render import _render_markdown
 from backend.schemas import ShareModel, StatusResponse
@@ -53,6 +54,27 @@ except Exception:  # pragma: no cover - WeasyPrint/GTK missing
 router = APIRouter(tags=["sharing"])
 
 
+def _gate_share(share: dict | None, user: dict | None) -> dict:
+    """#196 — directed shares: auth + membership check for ``/s/*`` pages.
+
+    Public share (``shared_with`` empty) → pass-through, no auth required.
+    Directed share → requires an authenticated user who is the creator, an
+    admin, or listed in ``shared_with``. Anything else answers **404** (never
+    403) so an outsider cannot learn that a token exists.
+    """
+    if share is None:
+        raise HTTPException(404, "Share not found or expired")
+    recipients = share.get("shared_with") or []
+    if not recipients:
+        return share
+    if user is None:
+        raise HTTPException(404, "Share not found or expired")
+    if user["username"] == share.get("created_by") or user.get("role") == "admin" \
+            or user["username"] in recipients:
+        return share
+    raise HTTPException(404, "Share not found or expired")
+
+
 @router.post("/api/share/{vault_name}", response_model=ShareModel)
 async def api_share_create(
     vault_name: str,
@@ -68,7 +90,14 @@ async def api_share_create(
         raise HTTPException(403, f"Accès refusé à la vault '{vault_name}'")
     path = body.get("path", "")
     expires = body.get("expires_in_hours")
-    share = create_share(vault_name, path, current_user["username"], expires)
+    # #196 — directed share: validate recipients before creating anything.
+    recipients = body.get("shared_with") or []
+    if not isinstance(recipients, list):
+        raise HTTPException(400, "shared_with doit être une liste d'utilisateurs")
+    for name in recipients:
+        if not isinstance(name, str) or not get_user(name):
+            raise HTTPException(400, f"Utilisateur inconnu : {name}")
+    share = create_share(vault_name, path, current_user["username"], expires, recipients)
     share["url"] = f"/s/{share['token']}"
 
     # Set publish: true in the file's frontmatter
@@ -94,8 +123,13 @@ async def api_share_create(
 
 @router.get("/api/shares", response_model=list[ShareModel])
 async def api_shares_list(vault: str | None = Query(None), current_user=Depends(require_auth)):
-    """List all shares (optionally filtered by vault)."""
-    shares = list_shares(vault)
+    """List shares (optionally filtered by vault).
+
+    #196 : un non-admin ne voit que SES partages (créés ou reçus) ; un admin
+    voit tout (comportement historique).
+    """
+    username = None if current_user.get("role") == "admin" else current_user["username"]
+    shares = list_shares(vault, username)
     for s in shares:
         s["url"] = f"/s/{s['token']}"
     return shares
@@ -103,6 +137,12 @@ async def api_shares_list(vault: str | None = Query(None), current_user=Depends(
 
 @router.delete("/api/share/{share_id}", response_model=StatusResponse)
 async def api_share_revoke(share_id: str, current_user=Depends(require_auth)):
+    # #196 — only the creator or an admin may revoke; a recipient cannot.
+    from backend.share import _read
+    share = _read()["shares"].get(share_id)
+    if share and current_user.get("role") != "admin" \
+            and share.get("created_by") != current_user["username"]:
+        raise HTTPException(403, "Seul le créateur du partage peut le révoquer")
     if not revoke_share(share_id):
         raise HTTPException(404, "Share not found")
     return {"status": "revoked"}
@@ -113,13 +153,12 @@ async def api_share_revoke(share_id: str, current_user=Depends(require_auth)):
     response_class=Response,
     responses={200: {"content": {"application/pdf": {}}, "description": "Shared document as PDF"}},
 )
-async def public_share_pdf_download(token: str):
+async def public_share_pdf_download(token: str, current_user=Depends(get_current_user)):
     """Download shared document as real PDF via WeasyPrint."""
     if generate_pdf is None:
         raise HTTPException(501, "PDF export unavailable (WeasyPrint/GTK not available)")
     share = get_share_by_token(token)
-    if not share:
-        raise HTTPException(404, "Share not found or expired")
+    share = _gate_share(share, current_user)
     vault_data = get_vault_data(share["vault"])
     if not vault_data:
         raise HTTPException(404, "Vault not found")
@@ -147,11 +186,10 @@ async def public_share_pdf_download(token: str):
 
 
 @router.get("/s/{token}/raw", response_class=FileResponse)
-async def public_share_raw(token: str):
+async def public_share_raw(token: str, current_user=Depends(get_current_user)):
     """Download the raw (original) shared document."""
     share = get_share_by_token(token)
-    if not share:
-        raise HTTPException(404, "Share not found or expired")
+    share = _gate_share(share, current_user)
     vault_data = get_vault_data(share["vault"])
     if not vault_data:
         raise HTTPException(404, "Vault not found")
@@ -164,13 +202,12 @@ async def public_share_raw(token: str):
 
 
 @router.get("/s/{token}", response_class=HTMLResponse)
-async def public_share_view(request: Request, token: str):
-    """Public share view — no authentication required."""
+async def public_share_view(request: Request, token: str, current_user=Depends(get_current_user)):
+    """Public share view — no authentication required (unless directed #196)."""
     from backend.csp import inject_csp_nonce
 
     share = get_share_by_token(token)
-    if not share:
-        raise HTTPException(404, "Share not found or expired")
+    share = _gate_share(share, current_user)
     vault_data = get_vault_data(share["vault"])
     if not vault_data:
         raise HTTPException(404, "Vault not found")