Add aspnet-request-servervariable and aspnet-request-item layout renders

src/Shared/LayoutRenderers/AspNetHttpContextItemLayoutRenderer.cs

@@ -0,0 +1,67 @@
+using System.Text;
+using NLog.LayoutRenderers;
+using NLog.Config;
+#if !ASP_NET_CORE
+using System.Web;
+#else
+using Microsoft.AspNetCore.Http;
+#endif
+
+namespace NLog.Web.LayoutRenderers
+{
+    /// <summary>
+    /// ASP.NET HttpContext Item.
+    /// </summary>
+    /// <remarks>
+    /// Use this layout renderer to insert the value of the specified Item of the HttpContext
+    /// </remarks>
+    /// <example>
+    /// <para>Example usage of ${aspnet-httpcontext-item}:</para>
+    /// <code lang="NLog Layout Renderer">
+    /// ${aspnet-httpcontext-item:Item=v}
+    /// </code>
+    /// </example>
+    [LayoutRenderer("aspnet-httpcontext-item")]
+    public class AspNetHttpContextItemLayoutRenderer : AspNetLayoutRendererBase
+    {
+        /// <summary>
+        /// Gets or sets the item name. The Item collection variables having the specified name are rendered.
+        /// </summary>
+        [RequiredParameter]
+        [DefaultParameter]
+        public string Item { get; set; }
+
+        /// <inheritdoc />
+        protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
+        {
+            var httpContext = HttpContextAccessor.HttpContext;
+            if (httpContext == null)
+            {
+                return;
+            }
+
+            if (Item != null)
+            {
+                builder.Append(LookupItemValue(Item, httpContext));
+            }
+        }
+
+#if !ASP_NET_CORE
+        private static string LookupItemValue(string key, HttpContextBase httpContext)
+        {
+            return httpContext?.Request?[key];
+        }
+
+#else
+        private static string LookupItemValue(string key, HttpContext httpContext)
+        {
+            object itemValue = null;
+            if (httpContext.Items?.TryGetValue(key, out itemValue) ?? false)
+            {
+                return itemValue?.ToString();
+            }
+            return null;
+        }
+#endif
+    }
+}

src/Shared/LayoutRenderers/AspNetRequestServerVariableLayoutRenderer.cs

@@ -0,0 +1,61 @@
+#if !ASP_NET_CORE || ASP_NET_CORE3
+using System.Text;
+using NLog.LayoutRenderers;
+using NLog.Web.Internal;
+using NLog.Config;
+#if !ASP_NET_CORE
+using System.Web;
+#else
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.Features;
+#endif
+
+namespace NLog.Web.LayoutRenderers
+{
+    /// <summary>
+    /// ASP.NET Server Variable.
+    /// </summary>
+    /// <remarks>
+    /// Use this layout renderer to insert the value of the specified Server Variable
+    /// </remarks>
+    /// <example>
+    /// <para>Example usage of ${aspnet-request-servervariable}:</para>
+    /// <code lang="NLog Layout Renderer">
+    /// ${aspnet-request-servervariable:Item=v}
+    /// </code>
+    /// </example>
+    [LayoutRenderer("aspnet-request-servervariable")]
+    public class AspNetRequestServerVariableLayoutRenderer : AspNetLayoutRendererBase
+    {
+
+        /// <summary>
+        /// Gets or sets the ServerVariables item to be rendered.
+        /// </summary>
+        [RequiredParameter]
+        [DefaultParameter]
+        public string Item { get; set; }
+
+        /// <inheritdoc />
+        protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
+        {
+            if (Item != null)
+            {
+                builder.Append(LookupItemValue(Item, HttpContextAccessor.HttpContext));
+            }
+        }
+
+#if !ASP_NET_CORE
+        private static string LookupItemValue(string key, HttpContextBase httpContext)
+        {
+            return httpContext?.TryGetRequest()?.ServerVariables?[key];
+        }
+
+#elif ASP_NET_CORE3
+        private static string LookupItemValue(string key, HttpContext httpContext)
+        {
+            return httpContext?.TryGetFeatureCollection()?.Get<IServerVariablesFeature>()?[key];
+        }
+#endif
+    }
+}
+#endif

src/Shared/LayoutRenderers/AspNetRequestValueLayoutRenderer.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Text;
 using NLog.Config;
 using NLog.LayoutRenderers;
@@ -7,7 +6,7 @@
 using System.Web;
 #else
 using Microsoft.AspNetCore.Http;
-
+using Microsoft.AspNetCore.Http.Features;
 #endif
 
 namespace NLog.Web.LayoutRenderers
@@ -58,7 +57,7 @@ public class AspNetRequestValueLayoutRenderer : AspNetLayoutRendererBase
         /// <docgen category='Rendering Options' order='10' />
         public string Cookie { get; set; }
 
-#if !ASP_NET_CORE
+#if !ASP_NET_CORE || ASP_NET_CORE3
         /// <summary>
         /// Gets or sets the ServerVariables item to be rendered.
         /// </summary>
@@ -101,8 +100,12 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
 #if !ASP_NET_CORE
             else if (ServerVariable != null)
             {
-                value = httpRequest.ServerVariables?.Count > 0 ?
-                    httpRequest.ServerVariables[ServerVariable] : null;
+                value = LookupServerVariableValue(ServerVariable, httpRequest);
+            }
+#elif ASP_NET_CORE3
+            else if (ServerVariable != null)
+            {
+                value = LookupServerVariableValue(ServerVariable, HttpContextAccessor.HttpContext);
             }
 #endif
             else if (Header != null)
@@ -147,6 +150,12 @@ private static string LookupItemValue(string key, HttpRequestBase httpRequest)
         {
             return httpRequest[key];
         }
+
+        private static string LookupServerVariableValue(string key, HttpRequestBase httpRequest)
+        {
+            var collection = httpRequest.ServerVariables;
+            return collection?.Count > 0 ? collection[key] : null;
+        }
 #else
         private static string LookupQueryString(string key, HttpRequest httpRequest)
         {
@@ -206,5 +215,12 @@ private static string LookupItemValue(string key, HttpRequest httpRequest)
             return null;
         }
 #endif
+
+#if ASP_NET_CORE3
+        private static string LookupServerVariableValue(string key, HttpContext httpContext)
+        {
+            return httpContext?.TryGetFeatureCollection()?.Get<IServerVariablesFeature>()?[key];
+        }
+#endif
     }
 }

tests/Shared/LayoutRenderers/AspNetHttpContextItemLayoutRendererTests.cs

@@ -0,0 +1,59 @@
+using System.IO;
+#if !ASP_NET_CORE
+using System.Collections.Specialized;
+using System.Web;
+using System.Web.Routing;
+using System.Web.SessionState;
+#else
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.Features;
+using Microsoft.Extensions.Primitives;
+using HttpContextBase = Microsoft.AspNetCore.Http.HttpContext;
+#endif
+using NLog.Common;
+using NLog.Web.LayoutRenderers;
+using NSubstitute;
+using NSubstitute.ExceptionExtensions;
+using Xunit;
+using System.Collections.Generic;
+
+
+namespace NLog.Web.Tests.LayoutRenderers
+{
+    public class AspNetHttpContextItemLayoutRendererTests : TestInvolvingAspNetHttpContext
+    {
+        [Fact]
+        public void KeyNotFoundRendersEmptyString()
+        {
+            var httpContext = Substitute.For<HttpContextBase>();
+
+            var renderer = new AspNetHttpContextItemLayoutRenderer();
+            renderer.HttpContextAccessor = new FakeHttpContextAccessor(httpContext);
+            renderer.Item = "key";
+
+            string result = renderer.Render(new LogEventInfo());
+
+            Assert.Empty(result);
+        }
+
+        [Fact]
+        public void KeyFoundRendersValue()
+        {
+            var expectedResult = "value";
+            var httpContext = Substitute.For<HttpContextBase>();
+#if !ASP_NET_CORE
+            httpContext.Request["key"].Returns(expectedResult);
+#else
+            httpContext.Items.Returns(new Dictionary<object, object>() { { "key", expectedResult } });
+#endif
+
+            var renderer = new AspNetHttpContextItemLayoutRenderer();
+            renderer.HttpContextAccessor = new FakeHttpContextAccessor(httpContext);
+            renderer.Item = "key";
+
+            string result = renderer.Render(new LogEventInfo());
+
+            Assert.Equal(expectedResult, result);
+        }
+    }
+}

tests/Shared/LayoutRenderers/AspNetRequestServerVariableLayoutRendererTests.cs

@@ -0,0 +1,122 @@
+using System.IO;
+#if !ASP_NET_CORE
+using System.Collections.Specialized;
+using System.Web;
+using System.Web.Routing;
+using System.Web.SessionState;
+#else
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.Features;
+using Microsoft.Extensions.Primitives;
+using HttpContextBase = Microsoft.AspNetCore.Http.HttpContext;
+#endif
+using NLog.Common;
+using NLog.Web.LayoutRenderers;
+using NSubstitute;
+using NSubstitute.ExceptionExtensions;
+using Xunit;
+using System.Collections.Generic;
+
+
+namespace NLog.Web.Tests.LayoutRenderers
+{
+    public class AspNetRequestServerVariableLayoutRendererTests : TestInvolvingAspNetHttpContext
+    {
+
+#if !ASP_NET_CORE
+        [Fact]
+        public void NullRequestRendersEmptyStringWithoutLoggingError()
+        {
+            var internalLog = new StringWriter();
+            InternalLogger.LogWriter = internalLog;
+            InternalLogger.LogLevel = LogLevel.Error;
+
+            var httpContext = Substitute.For<HttpContextBase>();
+            httpContext.Request.Returns(x => { throw new HttpException(); });
+
+            var renderer = new AspNetRequestServerVariableLayoutRenderer();
+            renderer.HttpContextAccessor = new FakeHttpContextAccessor(httpContext);
+            renderer.Item = "key";
+
+            string result = renderer.Render(new LogEventInfo());
+
+            Assert.Empty(result);
+            Assert.True(string.IsNullOrEmpty(internalLog.ToString()));
+        }
+#endif
+
+#if !ASP_NET_CORE
+        [Fact]
+        public void KeyNotFoundRendersEmptyString()
+        {
+            var httpContext = Substitute.For<HttpContextBase>();
+
+            var renderer = new AspNetRequestServerVariableLayoutRenderer();
+            renderer.HttpContextAccessor = new FakeHttpContextAccessor(httpContext);
+            renderer.Item = "key";
+
+            string result = renderer.Render(new LogEventInfo());
+
+            Assert.Empty(result);
+        }
+
+        [Fact]
+        public void KeyFoundRendersValue()
+        {
+            var expectedResult = "value";
+            var httpContext = Substitute.For<HttpContextBase>();
+            httpContext.Request.ServerVariables.Returns(new NameValueCollection { { "key", expectedResult } });
+
+            var renderer = new AspNetRequestServerVariableLayoutRenderer();
+            renderer.HttpContextAccessor = new FakeHttpContextAccessor(httpContext);
+            renderer.Item = "key";
+
+            string result = renderer.Render(new LogEventInfo());
+
+            Assert.Equal(expectedResult, result);
+        }
+#endif
+
+#if ASP_NET_CORE3
+        [Fact]
+        public void KeyNotFoundRendersEmptyString()
+        {
+            var httpContext = Substitute.For<HttpContextBase>();
+
+            var serverVariablesFeature = Substitute.For<IServerVariablesFeature>();
+            var featureCollection = new FeatureCollection();
+            featureCollection.Set<IServerVariablesFeature>(serverVariablesFeature);
+            httpContext.Features.Returns(featureCollection);
+
+            var renderer = new AspNetRequestServerVariableLayoutRenderer();
+            renderer.HttpContextAccessor = new FakeHttpContextAccessor(httpContext);
+            renderer.Item = "key";
+
+            string result = renderer.Render(new LogEventInfo());
+
+            Assert.Empty(result);
+        }
+
+        [Fact]
+        public void KeyFoundRendersValue()
+        {
+            var expectedResult = "value";
+            var httpContext = Substitute.For<HttpContextBase>();
+
+            var serverVariablesFeature = Substitute.For<IServerVariablesFeature>();
+            serverVariablesFeature["key"].Returns(expectedResult);
+            var featureCollection = new FeatureCollection();
+            featureCollection.Set<IServerVariablesFeature>(serverVariablesFeature);
+            httpContext.Features.Returns(featureCollection);
+
+            var renderer = new AspNetRequestServerVariableLayoutRenderer();
+            renderer.HttpContextAccessor = new FakeHttpContextAccessor(httpContext);
+            renderer.Item = "key";
+
+            string result = renderer.Render(new LogEventInfo());
+
+            Assert.Equal(expectedResult, result);
+        }
+#endif
+    }
+}