Added ${aspnet-request-form} (#313)

* Added aspnet-request-form layout renderer that outputs all or some of the request form collection.

* Made the aspnet-request-form layout renderer output uniform in both asp.net core and .net

* Added unit tests for aspnet-request-form layout renderer.

* Fixed issues with the unit tests for aspnet-request-form not working in the AspNetCore.Tests project.

* Removed code duplication by changing to a foreach that works for both AspNetCore and .net framework .

* Changed Include and Exclude to case insensitive HashSets.

* Added unit test to cove exclude/include precedence and updated comments.

* Made AspNetRequestFormLayoutRenderer a subclass of AspNetLayoutMultiValueRendererBase

NLog.Web.AspNetCore.Tests/LayoutRenderers/AspNetRequestFormLayoutRendererTests.cs

@@ -0,0 +1,147 @@
+using NLog.Web.Tests.LayoutRenderers;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using NLog.Web.LayoutRenderers;
+using NLog.Web.Tests;
+using NSubstitute;
+using System.Collections.Specialized;
+#if ASP_NET_CORE
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Primitives;
+#else
+using System.Web;
+#endif
+using Xunit;
+
+namespace NLog.Web.Tests.LayoutRenderers
+{
+    public class AspNetRequestFormLayoutRendererTests : TestInvolvingAspNetHttpContext
+    {
+        [Fact]
+        public void ShouldReturnEmptyIfFormCollectionIsEmpty()
+        {
+            // Arrange
+            var expectedResult = "";
+            var renderer = CreateRenderer(false);
+
+            // Act
+            string result = renderer.Render(new LogEventInfo());
+
+            // Assert
+            Assert.Equal(expectedResult, result);
+        }
+
+        [Fact]
+        public void ShouldReturnAllIfDefaultsAreUsed()
+        {
+            // Arrange
+            var expectedResult = "id=1,name=Test Person,token=86abe8fe-2237-4f87-81af-0a4e522b4140";
+            var renderer = CreateRenderer();
+
+            // Act
+            string result = renderer.Render(new LogEventInfo());
+
+            // Assert
+            Assert.Equal(expectedResult, result);
+        }
+
+        [Fact]
+        public void ShouldReturnOnlySpecifiedIfIncludeIsUsed()
+        {
+            // Arrange
+            var expectedResult = "id=1,name=Test Person";
+            var renderer = CreateRenderer();
+            renderer.Include.Add("id");
+            renderer.Include.Add("name");
+
+            // Act
+            string result = renderer.Render(new LogEventInfo());
+
+            // Assert
+            Assert.Equal(expectedResult, result);
+        }
+
+        [Fact]
+        public void ShouldNotReturnKeysSpecidiedInExclude()
+        {
+            // Arrange
+            var expectedResult = "id=1,name=Test Person";
+            var renderer = CreateRenderer();
+            renderer.Exclude.Add("token");
+
+            // Act
+            string result = renderer.Render(new LogEventInfo());
+
+            // Assert
+            Assert.Equal(expectedResult, result);
+        }
+
+        [Fact]
+        public void ShouldUseTheSpecifiedSeparator()
+        {
+            // Arrange
+            var expectedResult = "id=1\r\nname=Test Person\r\ntoken=86abe8fe-2237-4f87-81af-0a4e522b4140";
+            var renderer = CreateRenderer();
+            renderer.ItemSeparator = "${newline}";
+
+            // Act
+            string result = renderer.Render(new LogEventInfo());
+
+            // Assert
+            Assert.Equal(expectedResult, result);
+        }
+
+        [Fact]
+        public void ExcludeShouldTakePrecedenceOverInclude()
+        {
+            // Arrange
+            var expectedResult = "name=Test Person";
+            var renderer = CreateRenderer();
+            renderer.Include.Add("id");
+            renderer.Include.Add("name");
+            renderer.Exclude.Add("id");
+
+            // Act
+            string result = renderer.Render(new LogEventInfo());
+
+            // Assert
+            Assert.Equal(expectedResult, result);
+        }
+
+        private AspNetRequestFormLayoutRenderer CreateRenderer(bool hasFormValues = true)
+        {
+#if ASP_NET_CORE
+            var httpContext = this.HttpContext;
+            httpContext.Request.ContentType = "application/x-www-form-urlencoded";
+#else
+            var httpContext = Substitute.For<HttpContextBase>();
+            httpContext.Request.ContentType.Returns("application/x-www-form-urlencoded");
+#endif
+
+            if (hasFormValues)
+            {
+#if ASP_NET_CORE
+                var formCollection = new FormCollection(new Dictionary<string, StringValues>{
+                    { "id","1" },
+                    { "name","Test Person" },
+                    { "token","86abe8fe-2237-4f87-81af-0a4e522b4140" }
+                });
+                httpContext.Request.Form = formCollection;
+#else
+                var formCollection = new NameValueCollection(){
+                    { "id","1" },
+                    { "name","Test Person" },
+                    { "token","86abe8fe-2237-4f87-81af-0a4e522b4140" }
+                };
+                httpContext.Request.Form.Returns(formCollection);
+#endif
+            }
+
+            return new AspNetRequestFormLayoutRenderer
+            {
+                HttpContextAccessor = new FakeHttpContextAccessor(httpContext)
+            };
+        }
+    }
+}

NLog.Web.AspNetCore/LayoutRenderers/AspNetRequestFormLayoutRenderer.cs

@@ -0,0 +1,94 @@
+using NLog.LayoutRenderers;
+using NLog.Web.Internal;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NLog.Web.LayoutRenderers
+{
+    /// <summary>
+    /// ASP.NET Request Form Data
+    /// </summary>
+    /// <example>
+    /// <para>Example usage of ${aspnet-request-form}:</para>
+    /// <code lang="NLog Layout Renderer">
+    /// ${aspnet-request-form} - Produces - All Form Data from the Request with each key/value pair separated by a comma.
+    /// ${aspnet-request-form:Include=id,name} - Produces - Only Form Data from the Request with keys "id" and "name".
+    /// ${aspnet-request-form:Exclude=id,name} - Produces - All Form Data from the Request except the keys "id" and "name".
+    /// ${aspnet-request-form:Include=id,name:Exclude=id} - Produces - Only Form Data from the Request with key "name" (<see cref="Exclude"/> takes precedence over <see cref="Include"/>).
+    /// ${aspnet-request-form:ItemSeparator=${newline}} - Produces - All Form Data from the Request with each key/value pair separated by a new line.
+    /// </code>
+    /// </example>
+    [LayoutRenderer("aspnet-request-form")]
+    public class AspNetRequestFormLayoutRenderer : AspNetLayoutMultiValueRendererBase
+    {
+        /// <summary>
+        /// Gets or sets the form keys to include in the output.  If omitted, all are included.  <see cref="Exclude"/> takes precedence over <see cref="Include"/>.
+        /// </summary>
+        /// <docgen category='Rendering Options' order='10' />
+#if ASP_NET_CORE
+        public ISet<string> Include { get; set; }
+#else
+        public HashSet<string> Include { get; set; }
+#endif
+
+        /// <summary>
+        /// Gets or sets the form keys to exclude from the output.  If omitted, none are excluded.  <see cref="Exclude"/> takes precedence over <see cref="Include"/>.
+        /// </summary>
+        /// <docgen category='Rendering Options' order='10' />
+#if ASP_NET_CORE
+        public ISet<string> Exclude { get; set; }
+#else
+        public HashSet<string> Exclude { get; set; }
+#endif
+
+        /// <summary>
+        /// Constructor
+        /// </summary>
+        public AspNetRequestFormLayoutRenderer()
+        {
+            Include = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+            Exclude = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+        }
+
+        /// <summary>
+        /// Renders the Form Collection from the HttpRequest and appends it to the specified <see cref="StringBuilder" />.
+        /// </summary>
+        /// <param name="builder"></param>
+        /// <param name="logEvent"></param>
+        protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
+        {
+            if (HttpContextAccessor?.HttpContext?.TryGetRequest() == null)
+            {
+                return;
+            }
+
+            var formDataToInclude = GetPairsToInclude();
+
+            if (formDataToInclude.Any())
+            {
+                SerializePairs(formDataToInclude, builder, logEvent);
+            }
+        }
+
+        private IEnumerable<KeyValuePair<string, string>> GetPairsToInclude()
+        {
+            var httpRequest = HttpContextAccessor?.HttpContext?.TryGetRequest();
+            var pairs = new List<KeyValuePair<string, string>>();
+
+            if (httpRequest.Form != null)
+            {
+                foreach (string key in httpRequest.Form.Keys)
+                {
+                    if ((!Include.Any() || Include.Contains(key)) && !Exclude.Contains(key))
+                    {
+                        pairs.Add(new KeyValuePair<string, string>(key, httpRequest.Form[key]));
+                    }
+                }
+            }
+
+            return pairs;
+        }
+    }
+}

NLog.Web.Tests/NLog.Web.Tests.csproj

@@ -92,6 +92,9 @@
     <Compile Include="..\NLog.Web.AspNetCore.Tests\LayoutRenderers\AspNetMvcActionRendererTests.cs" />
     <Compile Include="..\NLog.Web.AspNetCore.Tests\LayoutRenderers\AspNetCookieLayoutRendererTests.cs" />
     <Compile Include="..\NLog.Web.AspNetCore.Tests\LayoutRenderers\AspNetItemValueLayoutRendererTests.cs" />
+    <Compile Include="..\NLog.Web.AspNetCore.Tests\LayoutRenderers\AspNetRequestFormLayoutRendererTests.cs">
+      <Link>AspNetRequestFormLayoutRendererTests.cs</Link>
+    </Compile>
     <Compile Include="..\NLog.Web.AspNetCore.Tests\LayoutRenderers\AspNetRequestValueLayoutRendererTests.cs" />
     <Compile Include="..\NLog.Web.AspNetCore.Tests\LayoutRenderers\AspNetSessionIDLayoutRendererTests.cs" />
     <Compile Include="..\NLog.Web.AspNetCore.Tests\LayoutRenderers\AspNetSessionValueLayoutRendererTests.cs" />

NLog.Web/NLog.Web.csproj

@@ -68,6 +68,9 @@
     <Compile Include="..\NLog.Web.AspNetCore\LayoutRenderers\AspNetMvcControllerRenderer.cs" />
     <Compile Include="..\NLog.Web.AspNetCore\LayoutRenderers\AspNetMvcActionRenderer.cs" />
     <Compile Include="..\NLog.Web.AspNetCore\LayoutRenderers\AspNetMvcLayoutRendererBase.cs" />
+    <Compile Include="..\NLog.Web.AspNetCore\LayoutRenderers\AspNetRequestFormLayoutRenderer.cs">
+      <Link>AspNetRequestFormLayoutRenderer.cs</Link>
+    </Compile>
     <Compile Include="..\NLog.Web.AspNetCore\LayoutRenderers\AspNetRequestValueLayoutRenderer.cs" />
     <Compile Include="..\NLog.Web.AspNetCore\LayoutRenderers\AspNetRequestIpLayoutRenderer.cs" />
     <Compile Include="..\NLog.Web.AspNetCore\LayoutRenderers\AspNetSessionIdLayoutRenderer.cs" />