feat(liveview): header View link opens active design as read-only canvas

Add an authenticated GET /api/v1/liveview/config endpoint exposing the
configured LIVEVIEW_KEY to logged-in admins, so the UI builds a
ready-to-use share link. The header View button opens
/view?key=...&design=<activeDesignId>; LiveView forwards ?design=<id>
to the public endpoint, which renders that design's canvas.

ha-relevant: maybe

backend/app/api/routes/liveview.py

@@ -2,9 +2,11 @@ import hmac
 from typing import Any
 
 from fastapi import APIRouter, Depends, HTTPException, Query
+from pydantic import BaseModel
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from app.api.deps import get_current_user
 from app.core.config import settings
 from app.db.database import get_db
 from app.db.models import CanvasState, Design, Edge, Node
@@ -15,6 +17,26 @@ from app.schemas.nodes import NodeResponse
 router = APIRouter()
 
 
+class LiveViewConfigResponse(BaseModel):
+    """Whether live view is enabled, plus the key (admin-only) to build share links."""
+
+    enabled: bool
+    key: str | None = None
+
+
+@router.get("/config", response_model=LiveViewConfigResponse)
+async def liveview_config(
+    _: str = Depends(get_current_user),
+) -> LiveViewConfigResponse:
+    """Authenticated: expose the configured live view key so the UI can build a
+    ready-to-use share link (e.g. /view?key=...&design=<id>).
+
+    Only reachable by a logged-in user — the key is never exposed publicly.
+    """
+    key = settings.liveview_key or None
+    return LiveViewConfigResponse(enabled=bool(key), key=key)
+
+
 @router.get("", response_model=CanvasStateResponse)
 async def liveview_canvas(
     key: str | None = Query(default=None),

backend/tests/test_liveview.py

@@ -146,3 +146,84 @@ async def test_liveview_disabled_after_key_cleared(client: AsyncClient):
     res = await client.get("/api/v1/liveview?key=was-enabled")
     assert res.status_code == 403
     assert res.json()["detail"] == "Live view is disabled"
+
+
+# ── /config (authenticated) — key used to build share links ──────────────────
+
+@pytest.mark.asyncio
+async def test_liveview_config_requires_auth(client: AsyncClient):
+    """The config endpoint exposes the key, so it must reject unauthenticated calls."""
+    settings.liveview_key = "secret"
+    res = await client.get("/api/v1/liveview/config")
+    assert res.status_code == 401
+
+
+@pytest.mark.asyncio
+async def test_liveview_config_returns_key_when_enabled(client: AsyncClient, auth_headers):
+    settings.liveview_key = "share-me"
+    headers = await auth_headers()
+    res = await client.get("/api/v1/liveview/config", headers=headers)
+    assert res.status_code == 200
+    body = res.json()
+    assert body == {"enabled": True, "key": "share-me"}
+
+
+@pytest.mark.asyncio
+async def test_liveview_config_disabled_hides_key(client: AsyncClient, auth_headers):
+    settings.liveview_key = None
+    headers = await auth_headers()
+    res = await client.get("/api/v1/liveview/config", headers=headers)
+    assert res.status_code == 200
+    assert res.json() == {"enabled": False, "key": None}
+
+
+@pytest.mark.asyncio
+async def test_liveview_config_empty_key_disabled(client: AsyncClient, auth_headers):
+    settings.liveview_key = ""
+    headers = await auth_headers()
+    res = await client.get("/api/v1/liveview/config", headers=headers)
+    assert res.status_code == 200
+    assert res.json() == {"enabled": False, "key": None}
+
+
+# ── design_id selects which canvas is rendered ───────────────────────────────
+
+@pytest.mark.asyncio
+async def test_liveview_design_id_selects_canvas(client: AsyncClient, auth_headers):
+    """?design_id=<id> renders that design's canvas, not the first one."""
+    settings.liveview_key = "test-key"
+    headers = await auth_headers()
+
+    # Create two designs
+    d1 = (await client.post("/api/v1/designs", json={"name": "Network"}, headers=headers)).json()
+    d2 = (await client.post("/api/v1/designs", json={"name": "Electrical"}, headers=headers)).json()
+
+    # Save a distinct node into each design
+    for design, node_id, label in ((d1, "n-net", "Net Node"), (d2, "n-elec", "Elec Node")):
+        payload = {
+            "nodes": [{
+                "id": node_id,
+                "type": "server",
+                "label": label,
+                "status": "online",
+                "services": [],
+                "pos_x": 0,
+                "pos_y": 0,
+            }],
+            "edges": [],
+            "viewport": {"x": 0, "y": 0, "zoom": 1},
+            "design_id": design["id"],
+        }
+        await client.post("/api/v1/canvas/save", json=payload, headers=headers)
+
+    # Requesting d2 returns only the electrical node
+    res = await client.get(f"/api/v1/liveview?key=test-key&design_id={d2['id']}")
+    assert res.status_code == 200
+    nodes = res.json()["nodes"]
+    assert [n["id"] for n in nodes] == ["n-elec"]
+
+    # Requesting d1 returns only the network node
+    res = await client.get(f"/api/v1/liveview?key=test-key&design_id={d1['id']}")
+    assert res.status_code == 200
+    nodes = res.json()["nodes"]
+    assert [n["id"] for n in nodes] == ["n-net"]

frontend/src/App.tsx

@@ -31,7 +31,7 @@ import { useCanvasStore } from '@/stores/canvasStore'
 import { useDesignStore } from '@/stores/designStore'
 import { useAuthStore } from '@/stores/authStore'
 import { useThemeStore } from '@/stores/themeStore'
-import { canvasApi, designsApi } from '@/api/client'
+import { canvasApi, designsApi, liveviewApi } from '@/api/client'
 import { demoNodes, demoEdges } from '@/utils/demoData'
 import { useStatusPolling } from '@/hooks/useStatusPolling'
 import type { NodeData, EdgeData, CustomStyleDef } from '@/types'
@@ -457,6 +457,28 @@ export default function App() {
     }
   }, [nodes, edges, snapshotHistory, loadCanvas, markUnsaved])
 
+  // Open the read-only live view of the currently active design in a new tab.
+  // Standalone has no backend/key — it reads localStorage, so just open /view.
+  // Otherwise fetch the configured live view key and build /view?key=...&design=<id>.
+  const handleViewOnly = useCallback(async () => {
+    if (STANDALONE) {
+      window.open('/view', '_blank', 'noopener,noreferrer')
+      return
+    }
+    try {
+      const res = await liveviewApi.getConfig()
+      if (!res.data.enabled || !res.data.key) {
+        toast.error('Live view is disabled — set LIVEVIEW_KEY in the backend .env')
+        return
+      }
+      const params = new URLSearchParams({ key: res.data.key })
+      if (activeDesignId) params.set('design', activeDesignId)
+      window.open(`/view?${params.toString()}`, '_blank', 'noopener,noreferrer')
+    } catch {
+      toast.error('Failed to open live view')
+    }
+  }, [activeDesignId])
+
   const handleExport = useCallback(() => {
     const el = canvasRef.current?.querySelector<HTMLElement>('.react-flow')
     if (!el) { toast.error('Canvas not ready'); return }
@@ -601,6 +623,7 @@ export default function App() {
               onExportMd={handleExportMd}
               onExportYaml={handleExportYaml}
               onImportYaml={handleImportYaml}
+              onViewOnly={handleViewOnly}
             />
             <div className="flex flex-1 min-h-0">
               <div ref={canvasRef} className="flex-1 min-w-0 h-full">

frontend/src/api/__tests__/client.test.ts

@@ -158,6 +158,16 @@ describe('api/client', () => {
     expect(api.get).not.toHaveBeenCalled()
   })
 
+  it('liveviewApi.load forwards design as design_id when provided', () => {
+    mod.liveviewApi.load('k-1', 'design-9')
+    expect(publicApi.get).toHaveBeenCalledWith('/liveview', { params: { key: 'k-1', design_id: 'design-9' } })
+  })
+
+  it('liveviewApi.getConfig hits the authenticated config endpoint', () => {
+    mod.liveviewApi.getConfig()
+    expect(api.get).toHaveBeenCalledWith('/liveview/config')
+  })
+
   it('scanApi endpoints route correctly', () => {
     mod.scanApi.trigger()
     expect(api.post).toHaveBeenCalledWith('/scan/trigger')

frontend/src/api/client.ts

@@ -53,7 +53,9 @@ export const edgesApi = {
 }
 
 export const liveviewApi = {
-  load: (key: string) => publicApi.get('/liveview', { params: { key } }),
+  load: (key: string, design?: string) =>
+    publicApi.get('/liveview', { params: { key, ...(design ? { design_id: design } : {}) } }),
+  getConfig: () => api.get<{ enabled: boolean; key: string | null }>('/liveview/config'),
 }
 
 export const scanApi = {

frontend/src/components/LiveView.tsx

@@ -68,10 +68,14 @@ function LiveViewCanvas() {
     }
 
     // Already handled synchronously in useState initializer
-    const key = new URLSearchParams(window.location.search).get('key')
+    const search = new URLSearchParams(window.location.search)
+    const key = search.get('key')
     if (!key) return
+    // Optional ?design=<id> selects which canvas to render; backend falls back
+    // to the first design when omitted.
+    const design = search.get('design') ?? undefined
 
-    liveviewApi.load(key)
+    liveviewApi.load(key, design)
       .then((res) => {
         const { nodes: apiNodes, edges: apiEdges } = res.data
         const proxmoxMap = new Map<string, boolean>(

frontend/src/components/__tests__/LiveView.test.tsx

@@ -118,7 +118,15 @@ describe('LiveView (non-standalone)', () => {
     await waitFor(() => {
       expect(screen.getByTestId('react-flow')).toBeDefined()
     })
-    expect(liveviewApi.load).toHaveBeenCalledWith('correct-key')
+    expect(liveviewApi.load).toHaveBeenCalledWith('correct-key', undefined)
+  })
+
+  it('forwards ?design=<id> to the API so a specific canvas is loaded', async () => {
+    setSearch('?key=correct-key&design=elec-123')
+    vi.mocked(liveviewApi.load).mockResolvedValue(canvasPayload as never)
+    render(<LiveView />)
+    await waitFor(() => expect(screen.getByTestId('react-flow')).toBeDefined())
+    expect(liveviewApi.load).toHaveBeenCalledWith('correct-key', 'elec-123')
   })
 
   it('allows zooming out to 0.25 so large infra fits (matches the editor)', async () => {

frontend/src/components/panels/Toolbar.tsx

@@ -1,5 +1,5 @@
 import { useRef } from 'react'
-import { Save, LayoutDashboard, Download, Palette, Undo2, Redo2, HelpCircle, Table2, FileDown, Upload } from 'lucide-react'
+import { Save, LayoutDashboard, Download, Palette, Undo2, Redo2, HelpCircle, Table2, FileDown, Upload, Eye } from 'lucide-react'
 import { Button } from '@/components/ui/button'
 import { Logo } from '@/components/ui/Logo'
 import { useCanvasStore } from '@/stores/canvasStore'
@@ -15,9 +15,10 @@ interface ToolbarProps {
   onExportMd: () => void
   onExportYaml: () => void
   onImportYaml: (content: string) => void
+  onViewOnly: () => void
 }
 
-export function Toolbar({ onSave, onAutoLayout, onExport, onChangeStyle, onUndo, onRedo, onShortcuts, onExportMd, onExportYaml, onImportYaml }: ToolbarProps) {
+export function Toolbar({ onSave, onAutoLayout, onExport, onChangeStyle, onUndo, onRedo, onShortcuts, onExportMd, onExportYaml, onImportYaml, onViewOnly }: ToolbarProps) {
   const { hasUnsavedChanges, past, future } = useCanvasStore()
   const fileInputRef = useRef<HTMLInputElement>(null)
 
@@ -81,6 +82,9 @@ export function Toolbar({ onSave, onAutoLayout, onExport, onChangeStyle, onUndo,
       <Button size="sm" variant="ghost" className="gap-1.5 text-muted-foreground hover:text-foreground cursor-pointer hover:bg-[#21262d]" onClick={onExportMd} title="Copy inventory as Markdown table">
         <Table2 size={14} /> MD
       </Button>
+      <Button size="sm" variant="ghost" className="gap-1.5 text-muted-foreground hover:text-foreground cursor-pointer hover:bg-[#21262d]" onClick={onViewOnly} title="Open read-only live view of this canvas">
+        <Eye size={14} /> View
+      </Button>
       <Button size="sm" variant="ghost" className="gap-1.5 text-muted-foreground hover:text-foreground cursor-pointer hover:bg-[#21262d]" onClick={onShortcuts} title="Keyboard shortcuts (?)">
         <HelpCircle size={14} />
       </Button>