feat(centralui+comm): IOpcUaBrowseService + typed BrowseOpcUaNodeAsync on CommunicationService

src/ZB.MOM.WW.ScadaBridge.CentralUI/ServiceCollectionExtensions.cs

@@ -50,6 +50,11 @@ public static class ServiceCollectionExtensions
         // Backs the Audit Log page's Export button via GET /api/centralui/audit/export.
         services.AddScoped<IAuditLogExportService, AuditLogExportService>();
 
+        // OPC UA Tag Browser (Task 14): facade over CommunicationService.BrowseOpcUaNodeAsync
+        // that enforces the CentralUI-side Design-role trust boundary and translates
+        // transport failures into typed BrowseFailure results for the dialog.
+        services.AddScoped<IOpcUaBrowseService, OpcUaBrowseService>();
+
         // Roslyn-backed C# analysis for the Monaco script editor.
         // Scoped because SharedScriptCatalog wraps a scoped service.
         services.AddMemoryCache(o => o.SizeLimit = 200);

src/ZB.MOM.WW.ScadaBridge.CentralUI/Services/IOpcUaBrowseService.cs

@@ -0,0 +1,37 @@
+using ZB.MOM.WW.ScadaBridge.Commons.Messages.Management;
+
+namespace ZB.MOM.WW.ScadaBridge.CentralUI.Services;
+
+/// <summary>
+/// CentralUI facade over the central-to-site OPC UA browse command. Backs the
+/// OPC UA Tag Browser dialog: each tree expansion / manual node-id paste calls
+/// <see cref="BrowseChildrenAsync"/>, which forwards a
+/// <see cref="BrowseOpcUaNodeCommand"/> to the owning site via
+/// <see cref="ZB.MOM.WW.ScadaBridge.Communication.CommunicationService"/>.
+/// </summary>
+/// <remarks>
+/// The service is the trust boundary for the browse capability: it enforces the
+/// <c>Design</c> role at central before any cross-cluster traffic is generated,
+/// because site-side actors do not unwrap the central trust envelope. Transport
+/// failures (timeouts, unreachable sites) are translated into a typed
+/// <see cref="BrowseFailure"/> so the dialog can render an inline error and
+/// remain usable (manual node-id paste still works).
+/// </remarks>
+public interface IOpcUaBrowseService
+{
+    /// <summary>
+    /// Enumerates the immediate children of an OPC UA node on the live server
+    /// backing <paramref name="dataConnectionId"/> at <paramref name="siteId"/>.
+    /// Pass <c>null</c> for <paramref name="parentNodeId"/> to browse from the
+    /// server root (ObjectsFolder).
+    /// </summary>
+    /// <param name="siteId">The target site identifier.</param>
+    /// <param name="dataConnectionId">Id of the site-local data connection to browse against.</param>
+    /// <param name="parentNodeId">Node to browse, or <c>null</c> to browse from the server root.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    Task<BrowseOpcUaNodeResult> BrowseChildrenAsync(
+        string siteId,
+        int dataConnectionId,
+        string? parentNodeId,
+        CancellationToken cancellationToken = default);
+}

src/ZB.MOM.WW.ScadaBridge.CentralUI/Services/OpcUaBrowseService.cs

@@ -0,0 +1,88 @@
+using Microsoft.AspNetCore.Components.Authorization;
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Protocol;
+using ZB.MOM.WW.ScadaBridge.Commons.Messages.Management;
+using ZB.MOM.WW.ScadaBridge.Communication;
+
+namespace ZB.MOM.WW.ScadaBridge.CentralUI.Services;
+
+/// <summary>
+/// Default <see cref="IOpcUaBrowseService"/> implementation — a thin facade over
+/// <see cref="CommunicationService.BrowseOpcUaNodeAsync"/> that enforces the
+/// CentralUI-side <c>Design</c>-role trust boundary and translates transport
+/// exceptions into a typed <see cref="BrowseFailure"/> result.
+/// </summary>
+/// <remarks>
+/// Site-side actors (<c>SiteCommunicationActor</c> + <c>DeploymentManagerActor</c>)
+/// do not unwrap the central trust envelope, so the role check MUST run here —
+/// never on the site. Transport failures collapse into <c>Timeout</c> or
+/// <c>ServerError</c> so the dialog can show an inline banner while leaving the
+/// manual node-id paste field usable.
+/// </remarks>
+public sealed class OpcUaBrowseService : IOpcUaBrowseService
+{
+    private readonly CommunicationService _communication;
+    private readonly AuthenticationStateProvider _auth;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="OpcUaBrowseService"/>.
+    /// </summary>
+    /// <param name="communication">Central-side cluster communication service.</param>
+    /// <param name="auth">Authentication state provider used for the Design-role guard.</param>
+    public OpcUaBrowseService(CommunicationService communication, AuthenticationStateProvider auth)
+    {
+        _communication = communication ?? throw new ArgumentNullException(nameof(communication));
+        _auth = auth ?? throw new ArgumentNullException(nameof(auth));
+    }
+
+    /// <inheritdoc/>
+    public async Task<BrowseOpcUaNodeResult> BrowseChildrenAsync(
+        string siteId,
+        int dataConnectionId,
+        string? parentNodeId,
+        CancellationToken cancellationToken = default)
+    {
+        // CentralUI-side role guard — sites don't enforce envelope-level roles,
+        // so the Design check must happen here before any cross-cluster traffic.
+        var state = await _auth.GetAuthenticationStateAsync();
+        if (!state.User.IsInRole("Design"))
+        {
+            return new BrowseOpcUaNodeResult(
+                Array.Empty<BrowseNode>(),
+                Truncated: false,
+                new BrowseFailure(BrowseFailureKind.ServerError, "Not authorized."));
+        }
+
+        try
+        {
+            return await _communication.BrowseOpcUaNodeAsync(
+                siteId,
+                new BrowseOpcUaNodeCommand(dataConnectionId, parentNodeId),
+                cancellationToken);
+        }
+        catch (TimeoutException ex)
+        {
+            // Akka Ask timed out — the site (or its OPC UA session) didn't answer
+            // within CommunicationOptions.QueryTimeout. Surface as a typed
+            // Timeout failure so the dialog can render an inline banner.
+            return new BrowseOpcUaNodeResult(
+                Array.Empty<BrowseNode>(),
+                Truncated: false,
+                new BrowseFailure(BrowseFailureKind.Timeout, ex.Message));
+        }
+        catch (OperationCanceledException)
+        {
+            // Caller-initiated cancel — propagate so Blazor can drop the response
+            // cleanly. Distinct from Timeout (which the dialog renders inline).
+            throw;
+        }
+        catch (Exception ex)
+        {
+            // Any other transport / serialization failure: keep the dialog
+            // alive and let the user fall back to manual node-id paste.
+            return new BrowseOpcUaNodeResult(
+                Array.Empty<BrowseNode>(),
+                Truncated: false,
+                new BrowseFailure(BrowseFailureKind.ServerError, ex.Message));
+        }
+    }
+}

src/ZB.MOM.WW.ScadaBridge.Communication/CommunicationService.cs

@@ -9,6 +9,7 @@ using ZB.MOM.WW.ScadaBridge.Commons.Messages.Health;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.InboundApi;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Integration;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Lifecycle;
+using ZB.MOM.WW.ScadaBridge.Commons.Messages.Management;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Notification;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.RemoteQuery;
 using ZB.MOM.WW.ScadaBridge.Communication.Actors;
@@ -346,6 +347,29 @@ public class CommunicationService
             envelope, _options.QueryTimeout, cancellationToken);
     }
 
+    // ── OPC UA Tag Browser (interactive design-time query) ──
+
+    /// <summary>
+    /// Asks a site to enumerate the immediate children of an OPC UA node on the
+    /// live server backing the given data connection. Used by the CentralUI OPC UA
+    /// Tag Browser dialog. The Ask is bounded by <see cref="CommunicationOptions.QueryTimeout"/>
+    /// — interactive browse expansions are short, one-shot queries that share the
+    /// same latency budget as other remote queries (event logs, parked messages).
+    /// </summary>
+    /// <param name="siteId">The target site identifier.</param>
+    /// <param name="command">The OPC UA browse command.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>The browse result (children + truncation flag + structured failure).</returns>
+    public Task<BrowseOpcUaNodeResult> BrowseOpcUaNodeAsync(
+        string siteId,
+        BrowseOpcUaNodeCommand command,
+        CancellationToken cancellationToken = default)
+    {
+        var envelope = new SiteEnvelope(siteId, command);
+        return GetActor().Ask<BrowseOpcUaNodeResult>(
+            envelope, _options.QueryTimeout, cancellationToken);
+    }
+
     // ── Pattern 8: Heartbeat (site→central, Tell) ──
     // Heartbeats are received by central, not sent. No method needed here.