55 lines
2.2 KiB
C#
55 lines
2.2 KiB
C#
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using System;
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using System.Linq;
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using System.Net.Http;
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using System.Threading.Tasks;
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using PluralKit.Core;
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using SixLabors.ImageSharp;
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namespace PluralKit.Bot {
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public static class AvatarUtils {
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public static async Task VerifyAvatarOrThrow(string url)
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{
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// List of MIME types we consider acceptable
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var acceptableMimeTypes = new[]
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{
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"image/jpeg",
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"image/gif",
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"image/png"
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// TODO: add image/webp once ImageSharp supports this
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};
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using (var client = new HttpClient())
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{
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Uri uri;
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try
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{
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uri = new Uri(url);
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if (!uri.IsAbsoluteUri) throw Errors.InvalidUrl(url);
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}
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catch (UriFormatException)
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{
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throw Errors.InvalidUrl(url);
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}
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var response = await client.GetAsync(uri);
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if (!response.IsSuccessStatusCode) // Check status code
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throw Errors.AvatarServerError(response.StatusCode);
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if (response.Content.Headers.ContentLength == null) // Check presence of content length
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throw Errors.AvatarNotAnImage(null);
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if (response.Content.Headers.ContentLength > Limits.AvatarFileSizeLimit) // Check content length
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throw Errors.AvatarFileSizeLimit(response.Content.Headers.ContentLength.Value);
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if (!acceptableMimeTypes.Contains(response.Content.Headers.ContentType.MediaType)) // Check MIME type
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throw Errors.AvatarNotAnImage(response.Content.Headers.ContentType.MediaType);
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// Parse the image header in a worker
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var stream = await response.Content.ReadAsStreamAsync();
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var image = await Task.Run(() => Image.Identify(stream));
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if (image == null) throw Errors.AvatarInvalid;
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if (image.Width > Limits.AvatarDimensionLimit || image.Height > Limits.AvatarDimensionLimit) // Check image size
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throw Errors.AvatarDimensionsTooLarge(image.Width, image.Height);
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}
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}
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}
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}
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