Adds Network Resource Uploading for admins. (#6904)

Co-authored-by: Pieter-Jan Briers <pieterjan.briers@gmail.com>
Co-authored-by: Pieter-Jan Briers <pieterjan.briers+git@gmail.com>

Content.Shared/Administration/SharedNetworkResourceManager.cs

@@ -0,0 +1,41 @@
+using Robust.Shared.ContentPack;
+using Robust.Shared.Network;
+using Robust.Shared.Utility;
+
+namespace Content.Shared.Administration;
+
+/// <summary>
+///     Manager that allows resources to be added at runtime by admins.
+///     They will be sent to all clients automatically.
+/// </summary>
+public abstract class SharedNetworkResourceManager : IDisposable
+{
+    [Dependency] private readonly INetManager _netManager = default!;
+    [Dependency] protected readonly IResourceManager ResourceManager = default!;
+
+    public const double BytesToMegabytes = 0.000001d;
+
+    /// <summary>
+    ///     The prefix for any and all downloaded network resources.
+    /// </summary>
+    private static readonly ResourcePath Prefix = ResourcePath.Root / "Uploaded";
+
+    protected readonly MemoryContentRoot ContentRoot = new();
+
+    public virtual void Initialize()
+    {
+        _netManager.RegisterNetMessage<NetworkResourceUploadMessage>(ResourceUploadMsg);
+
+        // Add our content root to the resource manager.
+        ResourceManager.AddRoot(Prefix, ContentRoot);
+    }
+
+    protected abstract void ResourceUploadMsg(NetworkResourceUploadMessage msg);
+
+    public void Dispose()
+    {
+        // This is called automatically when the IoCManager's dependency collection is cleared.
+        // MemoryContentRoot uses a ReaderWriterLockSlim, which we need to dispose of.
+        ContentRoot.Dispose();
+    }
+}