Allow browser cache by minutes and seconds

Author: JimBobSquarePants

src/ImageSharp.Web/Middleware/ImageContext.cs

@@ -127,7 +127,7 @@ public void ComprehendRequestHeaders(DateTimeOffset lastModified, long length)
         /// <returns>The <see cref="Task"/>.</returns>
         public Task SendStatusAsync(int statusCode, in ImageCacheMetadata metaData)
         {
-            this.ApplyResponseHeaders(statusCode, metaData.ContentType, this.ComputeMaxAge(metaData));
+            this.ApplyResponseHeaders(statusCode, metaData.ContentType, metaData.CacheControlMaxAge);
 
             // this.logger.LogHandled(statusCode, SubPath);
             return ResponseConstants.CompletedTask;
@@ -141,7 +141,7 @@ public Task SendStatusAsync(int statusCode, in ImageCacheMetadata metaData)
         /// <returns>The <see cref="Task"/>.</returns>
         public async Task SendAsync(Stream stream, ImageCacheMetadata metaData)
         {
-            this.ApplyResponseHeaders(ResponseConstants.Status200Ok, metaData.ContentType, this.ComputeMaxAge(metaData));
+            this.ApplyResponseHeaders(ResponseConstants.Status200Ok, metaData.ContentType, metaData.CacheControlMaxAge);
 
             if (stream.CanSeek)
             {
@@ -267,17 +267,5 @@ private void ComputeIfModifiedSince()
                 this.ifUnmodifiedSinceState = unmodified ? PreconditionState.ShouldProcess : PreconditionState.PreconditionFailed;
             }
         }
-
-        private TimeSpan ComputeMaxAge(in ImageCacheMetadata metaData)
-        {
-            // 14.9.3 CacheControl Max-Age
-            var maxAge = TimeSpan.FromDays(this.options.MaxBrowserCacheDays);
-            if (!metaData.CacheControlMaxAge.Equals(TimeSpan.MinValue))
-            {
-                maxAge = metaData.CacheControlMaxAge;
-            }
-
-            return maxAge;
-        }
     }
 }

src/ImageSharp.Web/Middleware/ImageSharpMiddleware.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
@@ -77,6 +78,11 @@ public class ImageSharpMiddleware
         /// </summary>
         private readonly DateTimeOffset minCacheLastWriteTimeUtc;
 
+        /// <summary>
+        /// The maximum time to store the response in a browser cache.
+        /// </summary>
+        private readonly TimeSpan maxBrowserCacheDuration;
+
         /// <summary>
         /// The collection of known commands gathered from the processors.
         /// </summary>
@@ -128,6 +134,7 @@ public ImageSharpMiddleware(
             this.cache = cache;
             this.cacheHash = cacheHash;
             this.minCacheLastWriteTimeUtc = this.GetMaxCacheDateTimeOffset();
+            this.maxBrowserCacheDuration = this.GetMaxBrowserCacheDuration();
 
             var commands = new HashSet<string>();
             foreach (IImageWebProcessor processor in this.processors)
@@ -256,9 +263,10 @@ private async Task ProcessRequestAsync(
                             format = image.Format;
                         }
 
-                        // Check to see if the source metadata has a cachecontrol max-age value and use it to
-                        // override the default max age from our options.
-                        var maxAge = TimeSpan.FromDays(this.options.MaxBrowserCacheDays);
+                        // 14.9.3 CacheControl Max-Age
+                        // Check to see if the source metadata has a CacheControl Max-Age value
+                        // and use it to override the default max age from our options.
+                        TimeSpan maxAge = this.maxBrowserCacheDuration;
                         if (!sourceImageMetadata.CacheControlMaxAge.Equals(TimeSpan.MinValue))
                         {
                             maxAge = sourceImageMetadata.CacheControlMaxAge;
@@ -416,5 +424,12 @@ private DateTimeOffset GetMaxCacheDateTimeOffset()
                 .AddMinutes(-this.options.MaxCacheMinutes)
                 .AddSeconds(-this.options.MaxCacheSeconds);
         }
+
+        private TimeSpan GetMaxBrowserCacheDuration()
+        {
+            return TimeSpan.FromDays(this.options.MaxBrowserCacheDays)
+                .Add(TimeSpan.FromMinutes(this.options.MaxBrowserCacheMinutes))
+                .Add(TimeSpan.FromSeconds(this.options.MaxBrowserCacheSeconds));
+        }
     }
 }

src/ImageSharp.Web/Middleware/ImageSharpMiddlewareOptions.cs

@@ -28,11 +28,23 @@ public class ImageSharpMiddlewareOptions
 
         /// <summary>
         /// Gets or sets the number of days to store images in the browser cache.
+        /// Defaults to 7.
         /// </summary>
         public int MaxBrowserCacheDays { get; set; } = 7;
 
+        /// <summary>
+        /// Gets or sets the number of minutes to store images in the browser cache.
+        /// </summary>
+        public int MaxBrowserCacheMinutes { get; set; }
+
+        /// <summary>
+        /// Gets or sets the number of seconds to store images in the browser cache.
+        /// </summary>
+        public int MaxBrowserCacheSeconds { get; set; }
+
         /// <summary>
         /// Gets or sets the number of days to store images in the image cache.
+        /// Defaults to 365.
         /// </summary>
         public int MaxCacheDays { get; set; } = 365;
 
@@ -47,7 +59,8 @@ public class ImageSharpMiddlewareOptions
         public int MaxCacheSeconds { get; set; }
 
         /// <summary>
-        /// Gets or sets the length of the filename to use (minus the extension) when storing images in the image cache.
+        /// Gets or sets the length of the filename to use (minus the extension) when storing
+        /// images in the image cache. Defaults to 12.
         /// </summary>
         public uint CachedNameLength { get; set; } = 12;