Adds variation by the header name Accept-Language to the delivery API output cache policy (#19709)

* Adds variation by the header name Accept-Language to the develivery API output cache policy

* Removed obsolete constructor (not necessary as the class is internal).

* Introduce contants for header names.

Author: AndyButland

src/Umbraco.Cms.Api.Delivery/Caching/DeliveryApiOutputCachePolicy.cs

@@ -1,15 +1,20 @@
-using Microsoft.AspNetCore.OutputCaching;
+using Microsoft.AspNetCore.OutputCaching;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Primitives;
 using Umbraco.Cms.Core.DeliveryApi;
 
 namespace Umbraco.Cms.Api.Delivery.Caching;
 
 internal sealed class DeliveryApiOutputCachePolicy : IOutputCachePolicy
 {
     private readonly TimeSpan _duration;
+    private readonly StringValues _varyByHeaderNames;
 
-    public DeliveryApiOutputCachePolicy(TimeSpan duration)
-        => _duration = duration;
+    public DeliveryApiOutputCachePolicy(TimeSpan duration, StringValues varyByHeaderNames)
+    {
+        _duration = duration;
+        _varyByHeaderNames = varyByHeaderNames;
+    }
 
     ValueTask IOutputCachePolicy.CacheRequestAsync(OutputCacheContext context, CancellationToken cancellationToken)
     {
@@ -20,6 +25,7 @@ ValueTask IOutputCachePolicy.CacheRequestAsync(OutputCacheContext context, Cance
 
         context.EnableOutputCaching = requestPreviewService.IsPreview() is false;
         context.ResponseExpirationTimeSpan = _duration;
+        context.CacheVaryByRules.HeaderNames = _varyByHeaderNames;
 
         return ValueTask.CompletedTask;
     }

src/Umbraco.Cms.Api.Delivery/DependencyInjection/UmbracoBuilderExtensions.cs

@@ -5,6 +5,7 @@
 using Microsoft.AspNetCore.Routing;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Primitives;
 using Umbraco.Cms.Api.Common.DependencyInjection;
 using Umbraco.Cms.Api.Delivery.Accessors;
 using Umbraco.Cms.Api.Delivery.Caching;
@@ -110,12 +111,20 @@ private static IUmbracoBuilder AddOutputCache(this IUmbracoBuilder builder)
 
             if (outputCacheSettings.ContentDuration.TotalSeconds > 0)
             {
-                options.AddPolicy(Constants.DeliveryApi.OutputCache.ContentCachePolicy, new DeliveryApiOutputCachePolicy(outputCacheSettings.ContentDuration));
+                options.AddPolicy(
+                    Constants.DeliveryApi.OutputCache.ContentCachePolicy,
+                    new DeliveryApiOutputCachePolicy(
+                        outputCacheSettings.ContentDuration,
+                        new StringValues([Constants.DeliveryApi.HeaderNames.AcceptLanguage, Constants.DeliveryApi.HeaderNames.AcceptSegment, Constants.DeliveryApi.HeaderNames.StartItem])));
             }
 
             if (outputCacheSettings.MediaDuration.TotalSeconds > 0)
             {
-                options.AddPolicy(Constants.DeliveryApi.OutputCache.MediaCachePolicy, new DeliveryApiOutputCachePolicy(outputCacheSettings.MediaDuration));
+                options.AddPolicy(
+                    Constants.DeliveryApi.OutputCache.MediaCachePolicy,
+                    new DeliveryApiOutputCachePolicy(
+                        outputCacheSettings.MediaDuration,
+                        Constants.DeliveryApi.HeaderNames.StartItem));
             }
         });
 

src/Umbraco.Cms.Api.Delivery/Filters/SwaggerContentDocumentationFilter.cs

@@ -1,4 +1,4 @@
-using Microsoft.OpenApi.Any;
+using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Models;
 using Swashbuckle.AspNetCore.SwaggerGen;
 using Umbraco.Cms.Api.Delivery.Configuration;
@@ -21,7 +21,7 @@ protected override void ApplyOperation(OpenApiOperation operation, OperationFilt
 
         operation.Parameters.Add(new OpenApiParameter
         {
-            Name = "Accept-Language",
+            Name = Core.Constants.DeliveryApi.HeaderNames.AcceptLanguage,
             In = ParameterLocation.Header,
             Required = false,
             Description = "Defines the language to return. Use this when querying language variant content items.",
@@ -35,7 +35,7 @@ protected override void ApplyOperation(OpenApiOperation operation, OperationFilt
 
         operation.Parameters.Add(new OpenApiParameter
         {
-            Name = "Accept-Segment",
+            Name = Core.Constants.DeliveryApi.HeaderNames.AcceptSegment,
             In = ParameterLocation.Header,
             Required = false,
             Description = "Defines the segment to return. Use this when querying segment variant content items.",
@@ -51,7 +51,7 @@ protected override void ApplyOperation(OpenApiOperation operation, OperationFilt
 
         operation.Parameters.Add(new OpenApiParameter
         {
-            Name = "Preview",
+            Name = Core.Constants.DeliveryApi.HeaderNames.Preview,
             In = ParameterLocation.Header,
             Required = false,
             Description = "Whether to request draft content.",
@@ -60,7 +60,7 @@ protected override void ApplyOperation(OpenApiOperation operation, OperationFilt
 
         operation.Parameters.Add(new OpenApiParameter
         {
-            Name = "Start-Item",
+            Name = Core.Constants.DeliveryApi.HeaderNames.StartItem,
             In = ParameterLocation.Header,
             Required = false,
             Description = "URL segment or GUID of a root content item.",

src/Umbraco.Cms.Api.Delivery/Filters/SwaggerDocumentationFilterBase.cs

@@ -1,4 +1,4 @@
-using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc;
 using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Models;
 using Swashbuckle.AspNetCore.SwaggerGen;
@@ -63,7 +63,7 @@ protected void AddFields(OpenApiOperation operation, OperationFilterContext cont
     protected void AddApiKey(OpenApiOperation operation) =>
         operation.Parameters.Add(new OpenApiParameter
         {
-            Name = "Api-Key",
+            Name = Core.Constants.DeliveryApi.HeaderNames.ApiKey,
             In = ParameterLocation.Header,
             Required = false,
             Description = "API key specified through configuration to authorize access to the API.",

src/Umbraco.Cms.Api.Delivery/Services/ApiAccessService.cs

@@ -1,4 +1,4 @@
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Options;
 using Umbraco.Cms.Core.Configuration.Models;
 using Umbraco.Cms.Core.DeliveryApi;
@@ -29,7 +29,7 @@ public ApiAccessService(IHttpContextAccessor httpContextAccessor, IOptionsMonito
     private bool IfEnabled(Func<bool> condition) => _deliveryApiSettings.Enabled && condition();
 
     private bool HasValidApiKey() => _deliveryApiSettings.ApiKey.IsNullOrWhiteSpace() == false
-                                     && _deliveryApiSettings.ApiKey.Equals(GetHeaderValue("Api-Key"));
+                                     && _deliveryApiSettings.ApiKey.Equals(GetHeaderValue(Core.Constants.DeliveryApi.HeaderNames.ApiKey));
 
     private bool IfMediaEnabled(Func<bool> condition) => _deliveryApiSettings is { Enabled: true, Media.Enabled: true } && condition();
 }

src/Umbraco.Cms.Api.Delivery/Services/RequestPreviewService.cs

@@ -11,5 +11,5 @@ public RequestPreviewService(IHttpContextAccessor httpContextAccessor)
     }
 
     /// <inheritdoc />
-    public bool IsPreview() => string.Equals(GetHeaderValue("Preview"), "true", StringComparison.OrdinalIgnoreCase);
+    public bool IsPreview() => string.Equals(GetHeaderValue(Core.Constants.DeliveryApi.HeaderNames.Preview), "true", StringComparison.OrdinalIgnoreCase);
 }

src/Umbraco.Cms.Api.Delivery/Services/RequestSegmentService.cs

@@ -1,4 +1,4 @@
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
 using Umbraco.Cms.Core.DeliveryApi;
 
 namespace Umbraco.Cms.Api.Delivery.Services;
@@ -12,5 +12,5 @@ public RequestSegmentService(IHttpContextAccessor httpContextAccessor)
 
     /// <inheritdoc />
     public string? GetRequestedSegment()
-        => GetHeaderValue("Accept-Segment");
+        => GetHeaderValue(Core.Constants.DeliveryApi.HeaderNames.AcceptSegment);
 }

src/Umbraco.Cms.Api.Delivery/Services/RequestStartItemProvider.cs

@@ -60,5 +60,5 @@ public RequestStartItemProvider(
     }
 
     /// <inheritdoc/>
-    public string? RequestedStartItem() => GetHeaderValue("Start-Item");
+    public string? RequestedStartItem() => GetHeaderValue(Constants.DeliveryApi.HeaderNames.StartItem);
 }

src/Umbraco.Core/Constants-DeliveryApi.cs

@@ -1,4 +1,4 @@
-namespace Umbraco.Cms.Core;
+namespace Umbraco.Cms.Core;
 
 public static partial class Constants
 {
@@ -24,14 +24,45 @@ public static class Routing
         public static class OutputCache
         {
             /// <summary>
-            ///     Output cache policy name for content
+            ///     Output cache policy name for content.
             /// </summary>
             public const string ContentCachePolicy = "DeliveryApiContent";
 
             /// <summary>
-            ///     Output cache policy name for media
+            ///     Output cache policy name for media.
             /// </summary>
             public const string MediaCachePolicy = "DeliveryApiMedia";
         }
+
+        /// <summary>
+        ///     Constants for Delivery API header names.
+        /// </summary>
+        public static class HeaderNames
+        {
+            /// <summary>
+            /// Header name for accept language.
+            /// </summary>
+            public const string AcceptLanguage = "Accept-Language";
+
+            /// <summary>
+            /// Header name for accept segment.
+            /// </summary>
+            public const string AcceptSegment = "Accept-Segment";
+
+            /// <summary>
+            /// Header name for API key.
+            /// </summary>
+            public const string ApiKey = "Api-Key";
+
+            /// <summary>
+            /// Header name for preview.
+            /// </summary>
+            public const string Preview = "Preview";
+
+            /// <summary>
+            /// Header name for start item.
+            /// </summary>
+            public const string StartItem = "Start-Item";
+        }
     }
 }