first commit

Infrastructure/App/Web/HttpContextLocal.cs

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+using Microsoft.AspNetCore.Http;
+using System;
+using System.Linq.Expressions;
+using System.Reflection;
+using System.Threading;
+
+namespace Microsoft.AspNetCore.Http
+{
+    public static class HttpContextLocal
+    {
+        private static Func<object> _asyncLocalAccessor;
+        private static Func<object, object> _holderAccessor;
+        private static Func<object, HttpContext> _httpContextAccessor;
+
+        /// <summary>
+        /// 获取当前 HttpContext 对象
+        /// </summary>
+        /// <returns></returns>
+        public static HttpContext Current()
+        {
+            var asyncLocal = (_asyncLocalAccessor ??= CreateAsyncLocalAccessor())();
+            if (asyncLocal == null) return null;
+
+            var holder = (_holderAccessor ??= CreateHolderAccessor(asyncLocal))(asyncLocal);
+            if (holder == null) return null;
+
+            return (_httpContextAccessor ??= CreateHttpContextAccessor(holder))(holder);
+
+            // 创建异步本地访问器
+            static Func<object> CreateAsyncLocalAccessor()
+            {
+                var fieldInfo = typeof(HttpContextAccessor).GetField("_httpContextCurrent", BindingFlags.Static | BindingFlags.NonPublic);
+                var field = Expression.Field(null, fieldInfo);
+                return Expression.Lambda<Func<object>>(field).Compile();
+            }
+
+            // 创建常驻 HttpContext 访问器
+            static Func<object, object> CreateHolderAccessor(object asyncLocal)
+            {
+                var holderType = asyncLocal.GetType().GetGenericArguments()[0];
+                var method = typeof(AsyncLocal<>).MakeGenericType(holderType).GetProperty("Value").GetGetMethod();
+                var target = Expression.Parameter(typeof(object));
+                var convert = Expression.Convert(target, asyncLocal.GetType());
+                var getValue = Expression.Call(convert, method);
+                return Expression.Lambda<Func<object, object>>(getValue, target).Compile();
+            }
+
+            // 获取 HttpContext 访问器
+            static Func<object, HttpContext> CreateHttpContextAccessor(object holder)
+            {
+                var target = Expression.Parameter(typeof(object));
+                var convert = Expression.Convert(target, holder.GetType());
+                var field = Expression.Field(convert, "Context");
+                var convertAsResult = Expression.Convert(field, typeof(HttpContext));
+                return Expression.Lambda<Func<object, HttpContext>>(convertAsResult, target).Compile();
+            }
+        }
+    }
+}