session state

Author: andrewlock

CustomFeatureFilter/CustomFeatureFilter/ClaimsFeatureFilter.cs

@@ -9,22 +9,21 @@ namespace CustomFeatureFilter
     [FilterAlias("Claims")]
     public class ClaimsFeatureFilter : IFeatureFilter
     {
-        private readonly IHttpContextAccessor _httpContextAccesor;
+        private readonly IHttpContextAccessor _httpContextAccessor;
 
-        public ClaimsFeatureFilter(IHttpContextAccessor httpContextAccesor)
+        public ClaimsFeatureFilter(IHttpContextAccessor httpContextAccessor)
         {
-            _httpContextAccesor = httpContextAccesor ?? throw new ArgumentNullException(nameof(httpContextAccesor));
+            _httpContextAccessor = httpContextAccessor ?? throw new ArgumentNullException(nameof(httpContextAccessor));
         }
 
         public bool Evaluate(FeatureFilterEvaluationContext context)
         {
             var settings = context.Parameters.Get<ClaimsFilterSettings>();
 
-            var user = _httpContextAccesor.HttpContext.User;
+            var user = _httpContextAccessor.HttpContext.User;
 
             return settings.RequiredClaims
                 .All(claimType => user.HasClaim(claim => claim.Type == claimType));
         }
     }
-        
-}
+}

CustomFeatureFilter/CustomFeatureFilter/FeatureFlags.cs

@@ -4,5 +4,6 @@ public static class FeatureFlags
     {
         public const string Beta = "Beta";
         public const string NewWelcomeBanner = "NewWelcomeBanner";
+        public const string NewExperience = "NewExperience";
     }
 }

CustomFeatureFilter/CustomFeatureFilter/Pages/Index.cshtml

@@ -1,16 +1,13 @@
 @page
 @model IndexModel
+@inject Microsoft.FeatureManagement.IFeatureManagerSnapshot FeatureManager
 @{
     ViewData["Title"] = "Home page";
 }
 
-<feature name="@FeatureFlags.Beta">
-    <div class="alert alert-primary" role="alert">
-        Congratulations - You're in the Beta test!
-    </div>
-</feature>
-
-<div class="text-center">
-    <h1 class="display-4">@Model.WelcomeMessage</h1>
-    <p>Learn about <a href="https://docs.microsoft.com/aspnet/core">building Web apps with ASP.NET Core</a>.</p>
-</div>
+<ul>
+@for (var i = 0; i < 10; i++)
+{
+    <li>Flag is: @FeatureManager.IsEnabled(FeatureFlags.NewExperience)</li>
+}
+</ul>

CustomFeatureFilter/CustomFeatureFilter/SessionSessionManager.cs

@@ -0,0 +1,34 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.FeatureManagement;
+
+namespace CustomFeatureFilter
+{
+    public class SessionSessionManager : ISessionManager
+    {
+        private readonly IHttpContextAccessor _contextAccessor;
+        public SessionSessionManager(IHttpContextAccessor contextAccessor)
+        {
+            _contextAccessor = contextAccessor;
+        }
+
+        public void Set(string featureName, bool enabled)
+        {
+            var session = _contextAccessor.HttpContext.Session;
+            var sessionKey = $"feature_{featureName}";
+            session.Set(sessionKey, new[] {enabled ? (byte) 1 : (byte) 0});
+        }
+
+        public bool TryGet(string featureName, out bool enabled)
+        {
+            var session = _contextAccessor.HttpContext.Session;
+            if (session.TryGetValue($"feature_{featureName}", out var enabledBytes))
+            {
+                enabled = enabledBytes[0] == 1;
+                return true;
+            }
+
+            enabled = false;
+            return false;
+        }
+    }
+}

CustomFeatureFilter/CustomFeatureFilter/Startup.cs

@@ -13,7 +13,9 @@
 using CustomFeatureFilter.Data;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.FeatureManagement;
+using Microsoft.FeatureManagement.FeatureFilters;
 
 namespace CustomFeatureFilter
 {
@@ -46,8 +48,13 @@ public void ConfigureServices(IServiceCollection services)
 
             services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
 
+            services.AddSession();
+            services.AddHttpContextAccessor();
+            services.AddTransient<ISessionManager, SessionSessionManager>();
+
             services.AddFeatureManagement()
                     .AddFeatureFilter<ClaimsFeatureFilter>()
+                    .AddFeatureFilter<PercentageFilter>()
                     .UseDisabledFeaturesHandler(new RedirectDisabledFeatureHandler());
         }
 
@@ -71,6 +78,7 @@ public void Configure(IApplicationBuilder app, IHostingEnvironment env)
             app.UseCookiePolicy();
 
             app.UseAuthentication();
+            app.UseSession();
 
             app.UseMvc();
         }

CustomFeatureFilter/CustomFeatureFilter/appsettings.json

@@ -9,7 +9,17 @@
   },
   "AllowedHosts": "*",
   "FeatureManagement": {
-    "NewWelcomeBanner": true,
+    "NewWelcomeBanner": false,
+    "NewExperience": {
+      "EnabledFor": [
+        {
+          "Name": "Microsoft.Percentage",
+          "Parameters": {
+            "Value": 50
+          }
+        }
+      ]
+    },
     "Beta": {
       "EnabledFor": [
         {