Merge pull request #324 from LD-Reborn/319-feature-user-image-pre-loading

319 feature user image pre loading

src/Controllers/HomeController.cs

@@ -106,15 +106,15 @@ public class HomeController : Controller
         }
         if (size is null)
         {
-            return File(Convert.FromBase64String(user.JpegPhoto), "image/jpeg");
+            return File(Convert.FromBase64String(user.JpegPhoto), "image/webp");
         }
         if (size is not null)
         {
             AdminSettingsModel adminSettingsModel = await adminSettingsModelTask;
             size = Math.Min((int)size, adminSettingsModel.MaxDownloadableUserImageSize);
         }
-        string encodedFile = ImageHelper.ResizeAndConvertToBase64(Convert.FromBase64String(user.JpegPhoto), size ?? 32);
-        return File(Convert.FromBase64String(encodedFile), "image/jpeg");
+        byte[] encodedFile = ImageHelper.ResizeAndConvertToWebp(user.JpegPhoto, size ?? 32);
+        return File(encodedFile, "image/webp");
     }
 
 

src/Helpers/ImageHelper.cs

@@ -1,41 +1,38 @@
 using SixLabors.ImageSharp;
-using SixLabors.ImageSharp.Processing;
-using SixLabors.ImageSharp.Formats.Jpeg;
-using System.IO;
-using SixLabors.ImageSharp.Formats.Gif;
-using SixLabors.ImageSharp.Processing.Processors.Quantization;
-using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Formats.Webp;
+using SixLabors.ImageSharp.Formats;
 
 namespace Berufsschule_HAM.Helpers;
 
 public static class ImageHelper
 {
-    public static string ResizeAndConvertToBase64(byte[] imageBytes, int size = 32)
+    public static Dictionary<int, Dictionary<string, byte[]>> ImageCache = [];
+    public static byte[] ResizeAndConvertToWebp(string imageString, int size = 32)
     {
-        using var inputStream = new MemoryStream(imageBytes);
-        using var image = Image.Load(inputStream);
-
-        // Optional: crop to square before resize
-        int minDimension = Math.Min(image.Width, image.Height);
-        var cropRectangle = new Rectangle(
-            (image.Width - minDimension) / 2,
-            (image.Height - minDimension) / 2,
-            minDimension,
-            minDimension);
-
-        image.Mutate(x =>
+        if (ImageCache.TryGetValue(size, out Dictionary<string, byte[]>? sizeCache)
+        && sizeCache.TryGetValue(imageString, out byte[]? result) && result.Length > 0)
         {
-            x.Crop(cropRectangle);
-            x.Resize(new ResizeOptions
-            {
-                Size = new Size(size, size),
-                Mode = ResizeMode.Crop
-            });
-        });
+            return result;
+        }
+        if (sizeCache is null) ImageCache[size] = [];
+        lock (ImageCache[size])
+        {
+            byte[] imageBytes = Convert.FromBase64String(imageString);
+            using var inputStream = new MemoryStream(imageBytes);
 
-        using var outputStream = new MemoryStream();
-        image.Save(outputStream, new WebpEncoder(){});
-        return Convert.ToBase64String(outputStream.ToArray());
+            var decoderOptions = new DecoderOptions
+            {
+                TargetSize = new Size(size, size),
+                SkipMetadata = true
+            };
+
+            using var image = Image.Load(decoderOptions, inputStream);
+
+            using var outputStream = new MemoryStream();
+            image.Save(outputStream, new WebpEncoder());
+            result = outputStream.ToArray();
+            ImageCache[size][imageString] = result;
+        }
+        return result;
     }
 }

src/Program.cs

@@ -12,6 +12,7 @@ var builder = WebApplication.CreateBuilder(args);
 builder.Services.Configure<LdapConfig>(builder.Configuration.GetSection("Ldap"));
 
 builder.Services.AddLocalization(options => options.ResourcesPath = "Resources");
+builder.Services.AddResponseCaching();
 
 builder.Services.AddControllersWithViews()
     .AddViewLocalization(Microsoft.AspNetCore.Mvc.Razor.LanguageViewLocationExpanderFormat.Suffix)