From 1b751781f0681a047f3d3d6097009478886ee2f5 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Tue, 27 Apr 2021 18:52:57 +0800
Subject: refactor: ...

---
 BackEnd/Timeline/Services/Imaging/ImageService.cs | 54 +++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 BackEnd/Timeline/Services/Imaging/ImageService.cs

(limited to 'BackEnd/Timeline/Services/Imaging/ImageService.cs')

diff --git a/BackEnd/Timeline/Services/Imaging/ImageService.cs b/BackEnd/Timeline/Services/Imaging/ImageService.cs
new file mode 100644
index 00000000..9fefe3e9
--- /dev/null
+++ b/BackEnd/Timeline/Services/Imaging/ImageService.cs
@@ -0,0 +1,54 @@
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.Formats;
+using System;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Timeline.Services.Imaging
+{
+
+    public class ImageService : IImageService
+    {
+        public async Task<IImageFormat> DetectFormatAsync(byte[] data, CancellationToken cancellationToken = default)
+        {
+            if (data == null)
+                throw new ArgumentNullException(nameof(data));
+
+            var format = await Task.Run(() =>
+            {
+                var format = Image.DetectFormat(data);
+                if (format is null)
+                {
+                    throw new ImageException(ImageException.ErrorReason.CantDecode, data, null, null, null);
+                }
+                return format;
+            }, cancellationToken);
+            return format;
+        }
+
+        public async Task<IImageFormat> ValidateAsync(byte[] data, string? requestType = null, bool square = false, CancellationToken cancellationToken = default)
+        {
+            if (data == null)
+                throw new ArgumentNullException(nameof(data));
+
+            var format = await Task.Run(() =>
+            {
+                try
+                {
+                    using var image = Image.Load(data, out IImageFormat format);
+                    if (requestType != null && !format.MimeTypes.Contains(requestType))
+                        throw new ImageException(ImageException.ErrorReason.UnmatchedFormat, data, requestType, format.DefaultMimeType);
+                    if (square && image.Width != image.Height)
+                        throw new ImageException(ImageException.ErrorReason.BadSize, data, requestType, format.DefaultMimeType);
+                    return format;
+                }
+                catch (UnknownImageFormatException e)
+                {
+                    throw new ImageException(ImageException.ErrorReason.CantDecode, data, requestType, null, null, e);
+                }
+            }, cancellationToken);
+            return format;
+        }
+    }
+}
-- 
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