Include the variation key in the response metadata

Author: rmja

src/HttpClient.Cache/Files/FileCache.cs

@@ -214,6 +214,7 @@ TimeProvider timeProvider
 
             var now = _timeProvider.GetUtcNow();
             var cachedResponse = await SetResponseImplAsync(
+                variationKey: null,
                 responseKey,
                 response,
                 now,
@@ -242,6 +243,7 @@ TimeProvider timeProvider
 
             // Write the response
             var cachedResponse = await SetResponseImplAsync(
+                variationKey,
                 responseKey,
                 response,
                 now,
@@ -268,6 +270,7 @@ TimeProvider timeProvider
     }
 
     private async Task<HttpResponseMessage> SetResponseImplAsync(
+        string? variationKey,
         string responseKey,
         HttpResponseMessage response,
         DateTimeOffset now,
@@ -278,7 +281,8 @@ CancellationToken cancellationToken
         var expiration = response.GetExpiration(now) ?? (now + DefaultInitialExpiration);
         var metadata = new MetadataModel()
         {
-            Key = responseKey,
+            VariationKey = variationKey,
+            ResponseKey = responseKey,
             Url = response.RequestMessage!.RequestUri!,
             Version = response.Version,
             StatusCode = response.StatusCode,

src/HttpClient.Cache/Files/MetadataModel.cs

@@ -4,7 +4,8 @@ namespace HttpClientCache.Files;
 
 public record MetadataModel
 {
-    public required string Key { get; init; }
+    public required string? VariationKey { get; init; }
+    public required string ResponseKey { get; init; }
     public required Uri Url { get; init; }
     public required Version Version { get; init; }
     public required HttpStatusCode StatusCode { get; init; }

src/HttpClient.Cache/Files/VariationFile.cs

@@ -52,7 +52,7 @@ public readonly async ValueTask WriteAsync(string key, Variation variation)
     {
         var model = new VariationModel
         {
-            Key = key,
+            VariationKey = key,
             CacheType = variation.CacheType,
             NormalizedVaryHeaders = variation.NormalizedVaryHeaders,
         };

src/HttpClient.Cache/Files/VariationModel.cs

@@ -2,7 +2,7 @@
 
 internal class VariationModel
 {
-    public required string Key { get; init; } = string.Empty;
+    public required string VariationKey { get; init; }
     public required CacheType CacheType { get; init; }
     public required List<string> NormalizedVaryHeaders { get; init; }
 }