Merge pull request #69 from crupest/image

Post image feature.

1 files changed, 53 insertions, 0 deletions

diff --git a/Timeline/Services/ImageValidator.cs b/Timeline/Services/ImageValidator.cs
new file mode 100644
index 00000000..c331d912
--- /dev/null
+++ b/Timeline/Services/ImageValidator.cs
@@ -0,0 +1,53 @@
+using SixLabors.ImageSharp;

+using SixLabors.ImageSharp.Formats;

+using System;

+using System.Linq;

+using System.Threading.Tasks;

+

+namespace Timeline.Services

+{

+    public interface IImageValidator

+    {

+        /// <summary>

+        /// Validate a image data.

+        /// </summary>

+        /// <param name="data">The data of the image. Can't be null.</param>

+        /// <param name="requestType">If not null, the real image format will be check against the requested format and throw if not match. If null, then do not check.</param>

+        /// <param name="square">If true, image must be square.</param>

+        /// <returns>The format.</returns>

+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="data"/> is null.</exception>

+        /// <exception cref="ImageException">Thrown when image data can't be decoded or real type does not match request type or image is not square when required.</exception>

+        Task<IImageFormat> Validate(byte[] data, string? requestType = null, bool square = false);

+    }

+

+    public class ImageValidator : IImageValidator

+    {

+        public ImageValidator()

+        {

+        }

+

+        public async Task<IImageFormat> Validate(byte[] data, string? requestType = null, bool square = false)

+        {

+            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.NotSquare, data, requestType, format.DefaultMimeType);

+                    return format;

+                }

+                catch (UnknownImageFormatException e)

+                {

+                    throw new ImageException(e, ImageException.ErrorReason.CantDecode, data, requestType, null);

+                }

+            });

+            return format;

+        }

+    }

+}