1 files changed, 70 insertions, 0 deletions
diff --git a/lib/VNLib.Plugins.Extensions.Loading/src/Routing/MiddlewareHelpers.cs b/lib/VNLib.Plugins.Extensions.Loading/src/Routing/MiddlewareHelpers.cs
new file mode 100644
index 0000000..6a0d848
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+++ b/lib/VNLib.Plugins.Extensions.Loading/src/Routing/MiddlewareHelpers.cs
@@ -0,0 +1,70 @@
+/*
+* Copyright (c) 2024 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Plugins.Extensions.Loading
+* File: MiddlewareHelpers.cs 
+*
+* MiddlewareHelpers.cs is part of VNLib.Plugins.Extensions.Loading which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* VNLib.Plugins.Extensions.Loading is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU Affero General Public License as 
+* published by the Free Software Foundation, either version 3 of the
+* License, or (at your option) any later version.
+*
+* VNLib.Plugins.Extensions.Loading is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU Affero General Public License for more details.
+*
+* You should have received a copy of the GNU Affero General Public License
+* along with this program.  If not, see https://www.gnu.org/licenses/.
+*/
+
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+
+using VNLib.Utils.Extensions;
+using VNLib.Plugins.Essentials.Middleware;
+
+namespace VNLib.Plugins.Extensions.Loading.Routing
+{
+    /// <summary>
+    /// Provides helper extensions for http middleware
+    /// </summary>
+    public static class MiddlewareHelpers
+    {
+        private static readonly ConditionalWeakTable<PluginBase, List<IHttpMiddleware>> _pluginMiddlewareList = new();
+
+        /// <summary>
+        /// Exports a single middlware instance to the collection for the plugin. 
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="plugin"></param>
+        /// <param name="instances">A params array of middleware instances to export to the plugin</param>
+        /// <remarks>
+        /// WARNING: Adding middleware arrays explicitly to the plugin service pool will override
+        /// this function. All instances must be exposed though this function
+        /// </remarks>
+        public static void ExportMiddleware<T>(this PluginBase plugin, params T[] instances) where T : IHttpMiddleware
+        {
+            /*
+              * The runtime accepts an enumeration of IHttpMiddleware instances, so 
+              * a list can just be exported as an enumerable instance
+              */
+            static List<IHttpMiddleware> OnCreate(PluginBase plugin)
+            {
+                List<IHttpMiddleware> collection = new(1);
+                plugin.ExportService<IEnumerable<IHttpMiddleware>>(collection);
+                return collection;
+            }
+
+            //Get the endpoint collection for the current plugin
+            List<IHttpMiddleware> middlewares = _pluginMiddlewareList.GetValue(plugin, OnCreate);
+
+            //Add the endpoint to the collection
+            instances.ForEach(mw => middlewares.Add(mw));
+        }
+    }
+}