proto(woo): per-browser Woo creds via X-Woo-* request headers

Prototype routing so 2–3 owners can share one store URL with different WP
application passwords. Device creds live in localStorage; server uses
request override → Settings fallback and never writes overrides into the
Settings row. Inference stays on shared Settings.

See PROTOTYPE.md for UAT with two browsers and known LAN forge risk.

backend/app.py

@@ -213,22 +213,23 @@ from .woo import (
     WooCredentialsMissing,
     WooError,
     WooForbiddenError,
+    client_for_request,
+    settings_woo_creds,
 )
 
 
 def _woo_credentials() -> tuple[str, str | None, str | None]:
-    conn = get_connection()
-    base = os.environ.get("WOO_BASE_URL", "")
-    user_row = conn.execute("SELECT value FROM settings WHERE key='woo_wp_username'").fetchone()
-    pass_row = conn.execute("SELECT value_enc FROM settings WHERE key='woo_app_password'").fetchone()
-    return base, (user_row[0] if user_row else None), (pass_row[0] if pass_row else None)
+    """Shop-default Woo creds (Settings). Used by health probe only."""
+    return settings_woo_creds(get_connection())
 
 
 @app.post("/api/v1/settings/test-woo")
-async def test_woo() -> dict[str, Any]:
-    base, username, enc_password = _woo_credentials()
+async def test_woo(request: Request) -> dict[str, Any]:
+    """Probe Woo + sync taxonomy. Optional X-Woo-Username / X-Woo-App-Password
+    override shop-default Settings for this request only (never persisted).
+    """
     try:
-        client = WooClient.from_settings(base, username, enc_password)
+        client = client_for_request(get_connection(), request.headers)
     except WooCredentialsMissing as e:
         return {
             "ok": False,
@@ -260,10 +261,10 @@ async def get_taxonomy() -> dict[str, Any]:
 
 
 @app.post("/api/v1/admin/taxonomy/sync")
-async def post_taxonomy_sync() -> dict[str, Any]:
-    base, username, enc_password = _woo_credentials()
+async def post_taxonomy_sync(request: Request) -> dict[str, Any]:
+    """Refresh taxonomy cache. Honors X-Woo-* override headers for this request."""
     try:
-        client = WooClient.from_settings(base, username, enc_password)
+        client = client_for_request(get_connection(), request.headers)
     except WooCredentialsMissing as e:
         return JSONResponse(status_code=502, content=_error("woo_unavailable", str(e)))
     try:

backend/publish.py

@@ -12,7 +12,7 @@ import re
 from datetime import datetime, timedelta, timezone
 from typing import Any
 
-from fastapi import APIRouter
+from fastapi import APIRouter, Request
 from fastapi.responses import JSONResponse
 
 from .db import get_connection
@@ -23,6 +23,8 @@ from .woo import (
     WooCredentialsMissing,
     WooError,
     WooForbiddenError,
+    client_for_request,
+    settings_woo_creds,
 )
 from .review import compute_ready, _slab_dict
 
@@ -139,7 +141,7 @@ def _classify(e: Exception) -> tuple[str, str, bool]:
 
 
 @router.post("/{slab_id}/publish")
-async def publish(slab_id: str) -> dict:
+async def publish(slab_id: str, request: Request) -> dict:
     conn = get_connection()
     row = conn.execute("SELECT * FROM slabs WHERE id=? AND deleted_at IS NULL", (slab_id,)).fetchone()
     if row is None:
@@ -150,9 +152,9 @@ async def publish(slab_id: str) -> dict:
     if not ready:
         return JSONResponse(status_code=422, content=_error("unpublishable", "Slab is not ready", {"missing": missing}))
     # 2. SKU lookup (PUBLISH-15) — stop if it exists in the store.
-    base, user, enc = _woo_creds(conn)
+    # Per-request Woo creds: X-Woo-* headers → Settings fallback (never persisted).
     try:
-        client = WooClient.from_settings(base, user, enc)
+        client = client_for_request(conn, request.headers)
     except WooCredentialsMissing as e:
         return JSONResponse(status_code=422, content=_error("woo_unconfigured", str(e)))
     try:
@@ -221,12 +223,8 @@ async def publish(slab_id: str) -> dict:
 
 
 def _woo_creds(conn) -> tuple[str, str | None, str | None]:
-    import os
-
-    base = os.environ.get("WOO_BASE_URL", "")
-    u = conn.execute("SELECT value FROM settings WHERE key='woo_wp_username'").fetchone()
-    p = conn.execute("SELECT value_enc FROM settings WHERE key='woo_app_password'").fetchone()
-    return base, (u[0] if u else None), (p[0] if p else None)
+    """Shop-default Woo creds (Settings). Prefer client_for_request for HTTP paths."""
+    return settings_woo_creds(conn)
 
 
 def _create_status(conn) -> str:

backend/tests/test_per_user_woo_creds.py

@@ -0,0 +1,113 @@
+"""Prototype: per-request X-Woo-* headers build distinct WooClients without clobbering Settings."""
+
+import base64
+import os
+import shutil
+import tempfile
+
+import pytest
+from starlette.datastructures import Headers
+
+import backend.db as db_mod
+from backend.crypto import encrypt, decrypt
+from backend.woo import (
+    WooClient,
+    client_for_request,
+    request_woo_override,
+    settings_woo_creds,
+    HEADER_WOO_USERNAME,
+    HEADER_WOO_APP_PASSWORD,
+)
+
+
+@pytest.fixture
+def db_dir():
+    tmp = tempfile.mkdtemp(prefix="per_user_woo_")
+    os.environ["SLAB_DB_PATH"] = os.path.join(tmp, "t.db")
+    os.environ["SLAB_IMAGES_DIR"] = tmp
+    os.environ["WOO_BASE_URL"] = "https://store.example.com"
+    os.environ["SLAB_AES_KEY"] = base64.b64encode(b"0123456789abcdef0123456789abcdef").decode()
+    db_mod._reset_for_tests()
+    conn = db_mod.init_db()
+    conn.execute(
+        "INSERT OR REPLACE INTO settings(key, value, value_enc) VALUES ('woo_wp_username','shop-default',NULL)"
+    )
+    conn.execute(
+        "INSERT OR REPLACE INTO settings(key, value, value_enc) VALUES ('woo_app_password',NULL,?)",
+        (encrypt("shop-secret"),),
+    )
+    conn.commit()
+    yield conn
+    db_mod._reset_for_tests()
+    shutil.rmtree(tmp, ignore_errors=True)
+
+
+def _auth_pair(client: WooClient) -> tuple[str, str]:
+    raw = base64.b64decode(client._auth).decode("utf-8")
+    user, password = raw.split(":", 1)
+    return user, password
+
+
+def test_override_headers_produce_distinct_auth_without_clobbering_settings(db_dir):
+    conn = db_dir
+    before = settings_woo_creds(conn)
+    assert before[1] == "shop-default"
+    assert decrypt(before[2]) == "shop-secret"
+
+    h_a = Headers({HEADER_WOO_USERNAME: "alice", HEADER_WOO_APP_PASSWORD: "alice-app-pw"})
+    h_b = Headers({HEADER_WOO_USERNAME: "bob", HEADER_WOO_APP_PASSWORD: "bob-app-pw"})
+
+    client_a = client_for_request(conn, h_a)
+    client_b = client_for_request(conn, h_b)
+    client_fallback = client_for_request(conn, Headers({}))
+
+    assert _auth_pair(client_a) == ("alice", "alice-app-pw")
+    assert _auth_pair(client_b) == ("bob", "bob-app-pw")
+    assert _auth_pair(client_fallback) == ("shop-default", "shop-secret")
+    assert client_a._auth != client_b._auth
+
+    after = settings_woo_creds(conn)
+    assert after == before
+    assert decrypt(after[2]) == "shop-secret"
+    # Explicit: Settings row values unchanged
+    row_u = conn.execute("SELECT value FROM settings WHERE key='woo_wp_username'").fetchone()[0]
+    row_p = conn.execute("SELECT value_enc FROM settings WHERE key='woo_app_password'").fetchone()[0]
+    assert row_u == "shop-default"
+    assert decrypt(row_p) == "shop-secret"
+
+
+def test_partial_headers_fall_back_to_settings(db_dir):
+    conn = db_dir
+    # Username only — incomplete override
+    assert request_woo_override(Headers({HEADER_WOO_USERNAME: "alice"})) is None
+    client = client_for_request(conn, Headers({HEADER_WOO_USERNAME: "alice"}))
+    assert _auth_pair(client) == ("shop-default", "shop-secret")
+
+
+def test_test_woo_endpoint_uses_request_override(db_dir, monkeypatch):
+    """API: POST /settings/test-woo with X-Woo-* builds client for that user."""
+    from fastapi.testclient import TestClient
+    from backend import app as app_mod
+
+    seen: list[str] = []
+
+    def fake_sync(client, conn):
+        seen.append(_auth_pair(client)[0])
+        return {"taxonomy_anchor": "x", "taxonomy_last_sync_at": "2026-01-01T00:00:00"}
+
+    monkeypatch.setattr(app_mod.taxonomy_mod, "sync", fake_sync)
+    tc = TestClient(app_mod.app)
+    r1 = tc.post(
+        "/api/v1/settings/test-woo",
+        headers={HEADER_WOO_USERNAME: "alice", HEADER_WOO_APP_PASSWORD: "pw-a"},
+    )
+    r2 = tc.post(
+        "/api/v1/settings/test-woo",
+        headers={HEADER_WOO_USERNAME: "bob", HEADER_WOO_APP_PASSWORD: "pw-b"},
+    )
+    r3 = tc.post("/api/v1/settings/test-woo")
+    assert r1.status_code == 200 and r1.json()["ok"] is True
+    assert r2.status_code == 200 and r2.json()["ok"] is True
+    assert r3.status_code == 200 and r3.json()["ok"] is True
+    assert seen == ["alice", "bob", "shop-default"]
+    assert settings_woo_creds(db_dir)[1] == "shop-default"

backend/woo.py

@@ -1,8 +1,12 @@
 """WooCommerce REST v3 client (stdlib urllib). Basic-auth, HTTPS-only, paginated.
 
-Creds come from Settings (wp_username plain, app_password AES-GCM). Missing creds
-raise WooCredentialsMissing (a fail-closed condition the caller maps to ok:false),
-distinct from WooAuthError (a 401 from the store).
+Default creds come from Settings (wp_username plain, app_password AES-GCM).
+Missing creds raise WooCredentialsMissing (fail-closed), distinct from
+WooAuthError (401 from the store).
+
+Prototype per-user override: callers may pass X-Woo-Username + X-Woo-App-Password
+request headers into client_for_request(); those build a per-request WooClient
+and are never written into Settings. See PROTOTYPE.md.
 """
 
 import base64
@@ -177,3 +181,53 @@ class WooClient:
         if code not in (200, 201):
             raise WooServerError(f"media upload returned {code}")
         return int(json.loads(resp)["id"])
+
+
+# --- Per-request Woo credential override (prototype) ---
+# Scheme: browser sends plaintext WP Application Password credentials on
+# Woo-touching API calls via:
+#   X-Woo-Username
+#   X-Woo-App-Password
+# Server uses those for THIS request's WooClient only; never writes them into
+# the Settings row. If either header is missing/blank, fall back to the
+# shop-default singleton (woo_wp_username + encrypted woo_app_password).
+
+HEADER_WOO_USERNAME = "X-Woo-Username"
+HEADER_WOO_APP_PASSWORD = "X-Woo-App-Password"
+
+
+def settings_woo_creds(conn) -> tuple[str, str | None, str | None]:
+    """Shop-default Woo creds from env + Settings (encrypted password)."""
+    import os
+
+    base = os.environ.get("WOO_BASE_URL", "")
+    u = conn.execute("SELECT value FROM settings WHERE key='woo_wp_username'").fetchone()
+    p = conn.execute("SELECT value_enc FROM settings WHERE key='woo_app_password'").fetchone()
+    return base, (u[0] if u else None), (p[0] if p else None)
+
+
+def request_woo_override(headers) -> tuple[str, str] | None:
+    """Return (username, app_password) if both override headers are present and non-blank."""
+    if headers is None:
+        return None
+    # Starlette Headers are case-insensitive
+    user = (headers.get(HEADER_WOO_USERNAME) or "").strip()
+    password = (headers.get(HEADER_WOO_APP_PASSWORD) or "").strip()
+    if user and password:
+        return user, password
+    return None
+
+
+def client_for_request(conn, headers=None, request: Callable[..., tuple[int, dict, bytes]] | None = None) -> WooClient:
+    """Build a WooClient for one HTTP request: override headers → Settings fallback.
+
+    Never mutates Settings. Inference stays on shared Settings (caller responsibility).
+    """
+    base, settings_user, settings_enc = settings_woo_creds(conn)
+    override = request_woo_override(headers)
+    if override is not None:
+        user, password = override
+        if request is None:
+            request = _default_request
+        return WooClient(user, password, base, request)
+    return WooClient.from_settings(base, settings_user, settings_enc, request=request)