ASP.NET Response Cookie Layout Renderer

src/NLog.Web.AspNetCore/NLog.Web.AspNetCore.csproj

@@ -75,7 +75,7 @@ NLog 5 release post: https://nlog-project.org/2021/08/25/nlog-5-0-preview1-ready
     <DefineConstants>$(DefineConstants);ASP_NET_CORE;ASP_NET_CORE3</DefineConstants>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="NLog.Extensions.Logging" Version="5.0.0" />
+	<PackageReference Include="NLog.Extensions.Logging" Version="5.0.0" />
   </ItemGroup>
   <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' or '$(TargetFramework)' == 'net461' ">
     <!-- Fixed to 2.1.0 as 2.1 is Long Term Supported (LTS) and works with vanilla .NET Core 2.1 SDK -->

src/Shared/LayoutRenderers/AspNetResponseCookieLayoutRenderer.cs

@@ -0,0 +1,180 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Sockets;
+using System.Text;
+using NLog.Config;
+using NLog.LayoutRenderers;
+using NLog.Web.Enums;
+using NLog.Web.Internal;
+#if !ASP_NET_CORE
+using System.Collections.Specialized;
+using System.Web;
+using Cookies = System.Web.HttpCookieCollection;
+#else
+using Microsoft.Extensions.Primitives;
+using Microsoft.Net.Http.Headers;
+using Microsoft.AspNetCore.Http;
+#endif
+
+namespace NLog.Web.LayoutRenderers
+{
+    /// <summary>
+    /// ASP.NET Response Cookie
+    /// </summary>
+    /// <example>
+    /// <para>Example usage of ${aspnet-response-cookie}</para>
+    /// <code lang="NLog Layout Renderer">
+    /// ${aspnet-response-cookie:OutputFormat=Flat}
+    /// ${aspnet-response-cookie:OutputFormat=JsonArray}
+    /// ${aspnet-response-cookie:OutputFormat=JsonDictionary}
+    /// ${aspnet-response-cookie:OutputFormat=JsonDictionary:CookieNames=username}
+    /// ${aspnet-response-cookie:OutputFormat=JsonDictionary:Exclude=access_token}
+    /// </code>
+    /// </example>
+    [LayoutRenderer("aspnet-response-cookie")]
+    public class AspNetResponseCookieLayoutRenderer : AspNetLayoutMultiValueRendererBase
+    {
+        /// <summary>
+        /// Cookie names to be rendered.
+        /// If <c>null</c> or empty array, all cookies will be rendered.
+        /// </summary>
+        public List<string> CookieNames { get; set; }
+
+        /// <summary>
+        /// Gets or sets the keys to exclude from the output. If omitted, none are excluded.
+        /// </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>
+        /// Initializes a new instance of the <see cref="AspNetResponseCookieLayoutRenderer" /> class.
+        /// </summary>
+        public AspNetResponseCookieLayoutRenderer()
+        {
+            Exclude = new HashSet<string>(new[] { "AUTH", "SESS_ID" }, StringComparer.OrdinalIgnoreCase);
+        }
+
+        /// <summary>
+        /// Renders the ASP.NET Cookie appends it to the specified <see cref="StringBuilder" />.
+        /// </summary>
+        /// <param name="builder">The <see cref="StringBuilder" /> to append the rendered data to.</param>
+        /// <param name="logEvent">Logging event.</param>
+        protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
+        {
+            var httpResponse = HttpContextAccessor.HttpContext.TryGetResponse();
+            if (httpResponse == null)
+            {
+                return;
+            }
+
+            var cookies = GetCookies(httpResponse);
+#if ASP_NET_CORE
+            if (cookies.Any())
+#else
+            if(cookies.Count > 0)
+#endif
+            {
+                bool checkForExclude = (CookieNames == null || CookieNames.Count == 0) && Exclude?.Count > 0;
+                var cookieValues = GetCookieValues(cookies, checkForExclude);
+                SerializePairs(cookieValues, builder, logEvent);
+            }
+        }
+
+#if !ASP_NET_CORE
+
+        /// <summary>
+        /// Method to get cookies for .NET Framework
+        /// </summary>
+        /// <param name="response"></param>
+        /// <returns></returns>
+        protected Cookies GetCookies(HttpResponseBase response)
+        {
+            return response.Cookies;
+        }
+
+        private List<string> GetCookieNames(HttpCookieCollection cookies)
+        {
+            return CookieNames?.Count > 0 ? CookieNames : cookies.Keys.Cast<string>().ToList();
+        }
+
+        private IEnumerable<KeyValuePair<string, string>> GetCookieValues(HttpCookieCollection cookies, bool checkForExclude)
+        {
+            var cookieNames = GetCookieNames(cookies);
+            foreach (var cookieName in cookieNames)
+            {
+                if (checkForExclude && Exclude.Contains(cookieName))
+                    continue;
+
+                var httpCookie = cookies[cookieName];
+                if (httpCookie == null)
+                {
+                    continue;
+                }
+
+                if (OutputFormat != AspNetRequestLayoutOutputFormat.Flat)
+                {
+                    // Split multi-valued cookie, as allowed for in the HttpCookie API for backwards compatibility with classic ASP
+                    var isFirst = true;
+                    foreach (var multiValueKey in httpCookie.Values.AllKeys)
+                    {
+                        var cookieKey = multiValueKey;
+                        if (isFirst)
+                        {
+                            cookieKey = cookieName;
+                            isFirst = false;
+                        }
+                        yield return new KeyValuePair<string, string>(cookieKey, httpCookie.Values[multiValueKey]);
+                    }
+                }
+                else
+                {
+                    yield return new KeyValuePair<string, string>(cookieName, httpCookie.Value);
+                }
+            }
+        }
+
+#else
+        /// <summary>
+        /// Method to get cookies for all ASP.NET Core versions
+        /// </summary>
+        /// <param name="response"></param>
+        /// <returns></returns>
+        protected IList<SetCookieHeaderValue> GetCookies(HttpResponse response)
+        {
+            var queryResults = response.Headers[HeaderNames.SetCookie];
+            if (queryResults.Count > 0 && SetCookieHeaderValue.TryParseList(queryResults, out var result))
+                return result;
+            else
+                return Array.Empty<SetCookieHeaderValue>();
+        }
+
+        private List<string> GetCookieNames(IEnumerable<SetCookieHeaderValue> cookies)
+        {
+            return CookieNames?.Count > 0 ? CookieNames : cookies.Select(row => row.Name.ToString()).ToList();
+        }
+
+        private IEnumerable<KeyValuePair<string, string>> GetCookieValues(IEnumerable<SetCookieHeaderValue> cookies, bool checkForExclude)
+        {
+            var cookieNames = GetCookieNames(cookies);
+            foreach (var cookieName in cookieNames)
+            {
+                if (checkForExclude && Exclude.Contains(cookieName))
+                    continue;
+
+                var httpCookie = cookies.SingleOrDefault(cookie => cookie.Name.ToString() == cookieName);
+                if (httpCookie == null)
+                {
+                    continue;
+                }
+
+                yield return new KeyValuePair<string, string>(cookieName, httpCookie.Value.ToString());
+            }
+        }
+#endif
+    }
+}