Fix AUI interaction checks (#7130)

Content.Server/UserInterface/ActivatableUIComponent.cs

@@ -33,6 +33,22 @@ namespace Content.Server.UserInterface
         [DataField("verbText")]
         public string VerbText = "ui-verb-toggle-open";
 
+        /// <summary>
+        ///     Whether you need a hand to operate this UI. The hand does not need to be free, you just need to have one.
+        /// </summary>
+        /// <remarks>
+        ///     This should probably be true for most machines & computers, but there will still be UIs that represent a
+        ///     more generic interaction / configuration that might not require hands.
+        /// </remarks>
+        [DataField("requireHands")]
+        public bool RequireHands = true;
+
+        /// <summary>
+        ///     Whether spectators (non-admin ghosts) should be allowed to view this UI.
+        /// </summary>
+        [DataField("allowSpectator")]
+        public bool AllowSpectator = true;
+
         /// <summary>
         ///     The client channel currently using the object, or null if there's none/not single user.
         ///     NOTE: DO NOT DIRECTLY SET, USE ActivatableUISystem.SetCurrentSingleUser

Content.Server/UserInterface/ActivatableUISystem.cs

@@ -1,8 +1,7 @@
 using Content.Server.Administration.Managers;
 using Content.Server.Ghost.Components;
-using Content.Shared.Actions;
-using Content.Shared.Actions.ActionTypes;
 using Content.Shared.Hands;
+using Content.Shared.Hands.Components;
 using Content.Shared.Interaction;
 using Content.Shared.Interaction.Events;
 using Content.Shared.Verbs;
@@ -28,12 +27,25 @@ namespace Content.Server.UserInterface
             // *THIS IS A BLATANT WORKAROUND!* RATIONALE: Microwaves need it
             SubscribeLocalEvent<ActivatableUIComponent, EntParentChangedMessage>(OnParentChanged);
             SubscribeLocalEvent<ActivatableUIComponent, BoundUIClosedEvent>(OnUIClose);
+            SubscribeLocalEvent<BoundUserInterfaceMessageAttempt>(OnBoundInterfaceInteractAttempt);
 
             SubscribeLocalEvent<ActivatableUIComponent, GetVerbsEvent<ActivationVerb>>(AddOpenUiVerb);
 
             SubscribeLocalEvent<ServerUserInterfaceComponent, OpenUiActionEvent>(OnActionPerform);
         }
 
+        private void OnBoundInterfaceInteractAttempt(BoundUserInterfaceMessageAttempt ev)
+        {
+            if (!TryComp(ev.Target, out ActivatableUIComponent? comp))
+                return;
+
+            if (!comp.RequireHands)
+                return;
+
+            if (!TryComp(ev.Sender.AttachedEntity, out SharedHandsComponent? hands) || hands.Hands.Count == 0)
+                ev.Cancel();
+        }
+
         private void OnActionPerform(EntityUid uid, ServerUserInterfaceComponent component, OpenUiActionEvent args)
         {
             if (args.Handled || args.Key == null)
@@ -57,7 +69,7 @@ namespace Content.Server.UserInterface
             if (component.InHandsOnly && args.Using != uid)
                 return;
 
-            if (!args.CanInteract && !HasComp<GhostComponent>(args.User))
+            if (!args.CanInteract && (!component.AllowSpectator || !HasComp<GhostComponent>(args.User)))
                 return;
 
             ActivationVerb verb = new();

Resources/Prototypes/Entities/Structures/Furniture/instruments.yml

@@ -6,6 +6,7 @@
   components:
   - type: Instrument
   - type: ActivatableUI
+    allowSpectator: false # otherwise they can play client-side music
     inHandsOnly: false
     singleUser: true
     verbText: verb-instrument-openui