Simple network replication for hands, untested.

Content.Client/Content.Client.csproj

@@ -62,6 +62,8 @@
     <Compile Include="EntryPoint.cs" />
     <Compile Include="Prototypes\DiscoBall.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="GameObjects\Components\Items\HandsComponent.cs" />
+    <Compile Include="Interfaces\GameObjects\Components\Items\IHandsComponent.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Content.Shared\Content.Shared.csproj">

Content.Client/EntryPoint.cs

@@ -1,4 +1,6 @@
-using SS14.Shared.ContentPack;
+using Content.Client.GameObjects;
+using Content.Client.Interfaces.GameObjects;
+using SS14.Shared.ContentPack;
 using SS14.Shared.Interfaces.GameObjects;
 using SS14.Shared.IoC;
 
@@ -12,6 +14,9 @@ namespace Content.Client
 
             factory.RegisterIgnore("Inventory");
             factory.RegisterIgnore("Item");
+
+            factory.Register<HandsComponent>();
+            factory.RegisterReference<HandsComponent, IHandsComponent>();
         }
     }
 }

Content.Client/GameObjects/Components/Items/HandsComponent.cs

@@ -0,0 +1,34 @@
+using Content.Client.Interfaces.GameObjects;
+using Content.Shared.GameObjects;
+using SS14.Shared.GameObjects;
+using SS14.Shared.Interfaces.GameObjects;
+using SS14.Shared.IoC;
+using System.Collections.Generic;
+
+namespace Content.Client.GameObjects
+{
+    public class HandsComponent : SharedHandsComponent, IHandsComponent
+    {
+        private readonly Dictionary<string, IEntity> hands = new Dictionary<string, IEntity>();
+
+        public IEntity GetEntity(string index)
+        {
+            if (hands.TryGetValue(index, out var entity))
+            {
+                return entity;
+            }
+
+            return null;
+        }
+
+        public override void HandleComponentState(ComponentState state)
+        {
+            var cast = (HandsComponentState)state;
+            hands.Clear();
+            foreach (var hand in cast.Hands)
+            {
+                hands[hand.Key] = Owner.EntityManager.GetEntity(hand.Value);
+            }
+        }
+    }
+}

Content.Client/Interfaces/GameObjects/Components/Items/IHandsComponent.cs

@@ -0,0 +1,16 @@
+using Content.Client.Interfaces.GameObjects;
+using Content.Shared.GameObjects;
+using SS14.Shared.GameObjects;
+using SS14.Shared.Interfaces.GameObjects;
+using SS14.Shared.IoC;
+using System.Collections.Generic;
+
+namespace Content.Client.Interfaces.GameObjects
+{
+    // HYPER SIMPLE HANDS API CLIENT SIDE.
+    // To allow for showing the HUD, mostly.
+    public interface IHandsComponent
+    {
+        IEntity GetEntity(string index);
+    }
+}

Content.Server/GameObjects/Components/Items/HandsComponent.cs

@@ -1,4 +1,5 @@
 using Content.Server.Interfaces.GameObjects;
+using Content.Shared.GameObjects;
 using SS14.Shared.GameObjects;
 using SS14.Shared.Interfaces.GameObjects;
 using SS14.Shared.Utility;
@@ -9,10 +10,8 @@ using YamlDotNet.RepresentationModel;
 
 namespace Content.Server.GameObjects
 {
-    public class HandsComponent : Component, IHandsComponent
+    public class HandsComponent : SharedHandsComponent, IHandsComponent
     {
-        public override string Name => "Hands";
-
         private string activeIndex;
         public string ActiveIndex
         {
@@ -54,8 +53,6 @@ namespace Content.Server.GameObjects
 
         public IEnumerable<IItemComponent> GetAllHeldItems()
         {
-            throw new NotImplementedException();
-            /*
             foreach (var slot in hands.Values)
             {
                 if (slot.Item != null)
@@ -63,7 +60,6 @@ namespace Content.Server.GameObjects
                     yield return slot.Item;
                 }
             }
-            */
         }
 
         public IItemComponent GetHand(string index)
@@ -77,8 +73,6 @@ namespace Content.Server.GameObjects
         /// </summary>
         private IEnumerable<string> ActivePriorityEnumerable()
         {
-            throw new NotImplementedException();
-            /*
             yield return ActiveIndex;
             foreach (var hand in hands.Keys)
             {
@@ -89,7 +83,6 @@ namespace Content.Server.GameObjects
 
                 yield return hand;
             }
-            */
         }
 
         public bool PutInHand(IItemComponent item)
@@ -183,5 +176,18 @@ namespace Content.Server.GameObjects
         ///     Get the name of the slot passed to the inventory component.
         /// </summary>
         private string HandSlotName(string index) => $"_hand_{index}";
+
+        public override ComponentState GetComponentState()
+        {
+            var dict = new Dictionary<string, int>(hands.Count);
+            foreach (var hand in hands)
+            {
+                if (hand.Value.Item != null)
+                {
+                    dict[hand.Key] = hand.Value.Item.Owner.Uid;
+                }
+            }
+            return new HandsComponentState(dict);
+        }
     }
 }

Content.Shared/Content.Shared.csproj

@@ -56,6 +56,8 @@
   <ItemGroup>
     <Compile Include="EntryPoint.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="GameObjects\Components\Items\HandsComponent.cs" />
+    <Compile Include="GameObjects\Components\NetIDs.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\engine\Lidgren.Network\Lidgren.Network.csproj">

Content.Shared/GameObjects/Components/Items/HandsComponent.cs

@@ -0,0 +1,25 @@
+using SS14.Shared.GameObjects;
+using System;
+using System.Collections.Generic;
+
+namespace Content.Shared.GameObjects
+{
+    public abstract class SharedHandsComponent : Component
+    {
+        public sealed override string Name => "Hands";
+        public sealed override uint? NetID => ContentNetIDs.HANDS;
+        public sealed override Type StateType => typeof(HandsComponentState);
+    }
+
+    // The IDs of the items get synced over the network.
+    [Serializable]
+    public class HandsComponentState : ComponentState
+    {
+        public readonly Dictionary<string, int> Hands;
+
+        public HandsComponentState(Dictionary<string, int> hands)
+        {
+            Hands = hands;
+        }
+    }
+}

Content.Shared/GameObjects/Components/NetIDs.cs

@@ -0,0 +1,7 @@
+namespace Content.Shared.GameObjects
+{
+    public static class ContentNetIDs
+    {
+        public const uint HANDS = 0;
+    }
+}