From 03f2293800fc3f40c6db902b492278c155c0d813 Mon Sep 17 00:00:00 2001
From: Jaxel Rojas <jaxelr@gmail.com>
Date: Wed, 25 Jan 2023 08:06:37 -0400
Subject: [PATCH] refactor: moved checksum calculation to middleware

---
 src/Carter.Cache/CarterCachingMiddleware.cs   | 19 +++++++++++++++++--
 .../Extensions/HttpContextExtensions.cs       | 13 -------------
 .../Unit/CachingServiceFxtures.cs             |  2 +-
 3 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/src/Carter.Cache/CarterCachingMiddleware.cs b/src/Carter.Cache/CarterCachingMiddleware.cs
index 5e560aa..1c380fd 100644
--- a/src/Carter.Cache/CarterCachingMiddleware.cs
+++ b/src/Carter.Cache/CarterCachingMiddleware.cs
@@ -1,4 +1,7 @@
-using System.IO;
+using System;
+using System.IO;
+using System.Linq;
+using System.Security.Cryptography;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
 
@@ -48,7 +51,7 @@ private async Task SetCache(HttpContext ctx, RequestDelegate next, CachingOption
 
             if (options.ValidResponse(ctx))
             {
-                string checksum = ctx.CalculateChecksum(bytes);
+                string checksum = CalculateChecksum(bytes);
                 ctx.AddEtagToContext(checksum);
 
                 if (memoryStream.Length > 0)
@@ -68,4 +71,16 @@ private async Task SetCache(HttpContext ctx, RequestDelegate next, CachingOption
     }
 
     private async Task<bool> CheckCache(HttpContext ctx, CachingOption options) => await service.CheckCache(ctx, options);
+
+    internal static string CalculateChecksum(byte[] content)
+    {
+        if (content.Length == 0) //Dont process an empty byte array
+        {
+            return string.Empty;
+        }
+
+        using var sha1 = SHA1.Create();
+
+        return Convert.ToBase64String(sha1.ComputeHash(content.ToArray()));
+    }
 }
diff --git a/src/Carter.Cache/Extensions/HttpContextExtensions.cs b/src/Carter.Cache/Extensions/HttpContextExtensions.cs
index 97bec24..ebf0b2b 100644
--- a/src/Carter.Cache/Extensions/HttpContextExtensions.cs
+++ b/src/Carter.Cache/Extensions/HttpContextExtensions.cs
@@ -1,6 +1,4 @@
 using System;
-using System.Linq;
-using System.Security.Cryptography;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Net.Http.Headers;
 
@@ -44,15 +42,4 @@ internal static void AddEtagToContext(this HttpContext ctx, string checksum)
 
         ctx.Response.Headers[HeaderNames.ETag] = $"\"{checksum}\"";
     }
-
-    internal static string CalculateChecksum(this HttpContext ctx, byte[] content)
-    {
-        if (content.Length == 0) //Dont process an empty byte array
-        {
-            return string.Empty;
-        }
-
-        using var sha1 = SHA1.Create();
-        return Convert.ToBase64String(sha1.ComputeHash(content.ToArray()));
-    }
 }
diff --git a/tests/Carter.Cache.Tests/Unit/CachingServiceFxtures.cs b/tests/Carter.Cache.Tests/Unit/CachingServiceFxtures.cs
index ae4c233..5ae4a74 100644
--- a/tests/Carter.Cache.Tests/Unit/CachingServiceFxtures.cs
+++ b/tests/Carter.Cache.Tests/Unit/CachingServiceFxtures.cs
@@ -158,7 +158,7 @@ public async Task Service_set_cache_default_with_request_body()
         A.CallTo(() => response.StatusCode).Returns(StatusCodes.Status200OK);
 
         A.CallTo(() => response.Headers.ContainsKey(HeaderNames.ETag)).Returns(true);
-        A.CallTo(() => response.Headers[HeaderNames.ETag]).Returns(ctx.CalculateChecksum(body));
+        A.CallTo(() => response.Headers[HeaderNames.ETag]).Returns(CarterCachingMiddleware.CalculateChecksum(body));
 
         var cachedResponse = new CachedResponse(ctx, body);