Radicade Public Code

Server/Images/ImageAPI.cs

@@ -0,0 +1,203 @@
+using Microsoft.AspNetCore.Mvc;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.Processing;
+using SixLabors.ImageSharp.Formats;
+
+namespace RadicadeServer.Images
+{
+	[Route("images")]
+	public class ImageAPI : Controller
+	{
+		private const string SignatureData =
+			"IWwe/pZ5vWWqNSkSM/54isgDxlZkdrP0sUrppKCbNktO2yCOTjq746xWiiLsueGuVcAGQqkjeRTimxolHckS/YXSYkEJxtiCXbLlsRia2DyAqtWVkGWsfczzFhp/56U66FVzolTspPCvjScOVlGO7dDIK7sJ+ndcRauWjsQsC6g3e7rUc6uwY099a6gy7sw6xr5BFZQSz8wg+fqyHYD/Sc4nQQVOTFZNNASqbJYhpNhEMXRnafCMuLl8a3mkGwvy3t4q2D/7SM48xrGZjEV47qNx1A91KCe28XVToFh4BzwEUU8nZ0d+KwV79MGarLo1cY8igc8FcoThKcovI4ClOg==";
+
+		public const string PatchedKeyId = "KEY:RSA:p1.radicade.internal";
+
+		public const string StockKeyId = "KEY:RSA:p1.rec.net";
+
+		public static readonly string SignatureString = BuildSignature(PatchedKeyId);
+
+		public static readonly string StockSignatureString = BuildSignature(StockKeyId);
+
+		public const string KeyIdQueryParameter = "rcsig";
+
+		public static readonly string BareRouteKeyId =
+			IsWellFormedKeyId(Environment.GetEnvironmentVariable("RADICADE_IMAGE_BARE_KEYID") ?? string.Empty)
+				? Environment.GetEnvironmentVariable("RADICADE_IMAGE_BARE_KEYID") ?? StockKeyId
+				: StockKeyId;
+
+		private static string BuildSignature(string keyId) => $"key-id={keyId}; data={SignatureData}";
+
+		[HttpGet("img/{imageName}")]
+		public async Task<IActionResult> GetImageFile(string imageName, [FromQuery] int? width, [FromQuery] int? cropSquare, [FromQuery] string sig,
+			[FromQuery(Name = KeyIdQueryParameter)] string clientKeyId)
+		{
+			return await ProcessImage(imageName, width, cropSquare, false, SignatureFor(clientKeyId, "img", PatchedKeyId));
+		}
+
+		[HttpGet("{imageName}")]
+		public async Task<IActionResult> GetImageFileAlt(string imageName, [FromQuery] int? width, [FromQuery] int? cropSquare, [FromQuery] string sig,
+			[FromQuery(Name = KeyIdQueryParameter)] string clientKeyId)
+		{
+			return await ProcessImage(imageName, width, cropSquare, false, SignatureFor(clientKeyId, "bare", BareRouteKeyId));
+		}
+
+		[HttpGet("default")]
+		public async Task<IActionResult> GetDefaultImage([FromQuery] int? width, [FromQuery] int? cropSquare, [FromQuery] string sig,
+			[FromQuery(Name = KeyIdQueryParameter)] string clientKeyId)
+		{
+			return await ProcessImage(DBConfig.DefaultRoomImage, width, cropSquare, false, SignatureFor(clientKeyId, "default", BareRouteKeyId));
+		}
+
+		public static string SignatureFor(string clientKeyId, string route, string routeDefaultKeyId)
+		{
+			var keyId = IsWellFormedKeyId(clientKeyId) ? clientKeyId : routeDefaultKeyId;
+			return BuildSignature(keyId);
+		}
+
+		public static bool IsWellFormedKeyId(string keyId)
+		{
+			const string prefix = "KEY:RSA:p1.";
+			if (string.IsNullOrEmpty(keyId) || keyId.Length > 96 || !keyId.StartsWith(prefix, StringComparison.Ordinal))
+				return false;
+			var tail = keyId.Substring(prefix.Length);
+			if (tail.Length == 0 || tail.Length > 64)
+				return false;
+			foreach (var c in tail)
+			{
+				if (!char.IsLetterOrDigit(c) && c != '.' && c != '-' && c != '_')
+					return false;
+			}
+			return true;
+		}
+
+		public static string[] AssetRoots() => new[] { DBConfig.CDNImages, DBConfig.CDNCustom, DBConfig.CDNStorage };
+
+		private static readonly string[] ExtensionVariants = { ".png", ".jpg", ".jpeg" };
+
+		public static string? ResolveAsset(string imageName) => ResolveAsset(imageName, AssetRoots());
+
+		public static string? ResolveAsset(string imageName, IEnumerable<string> roots)
+		{
+			var name = Path.GetFileName(imageName);
+			if (string.IsNullOrWhiteSpace(name) || name == "." || name == "..")
+				return null;
+
+			foreach (var candidate in CandidateNames(name))
+			{
+				foreach (var root in roots)
+				{
+					var path = Path.Join(root, candidate);
+					if (WithinRoot(root, path) && System.IO.File.Exists(path))
+					{
+						return path;
+					}
+				}
+			}
+
+			return null;
+		}
+
+		private static IEnumerable<string> CandidateNames(string name)
+		{
+			yield return name;
+
+			var existing = Path.GetExtension(name);
+
+			foreach (var variant in ExtensionVariants)
+			{
+				if (existing.Length == 0)
+				{
+					yield return name + variant;
+				}
+				else if (!string.Equals(existing, variant, StringComparison.OrdinalIgnoreCase))
+				{
+					yield return string.Concat(name.AsSpan(0, name.Length - existing.Length), variant);
+				}
+			}
+		}
+
+		private static bool WithinRoot(string root, string path)
+		{
+			try
+			{
+				var fullRoot = Path.GetFullPath(root) + Path.DirectorySeparatorChar;
+				return Path.GetFullPath(path).StartsWith(fullRoot, StringComparison.Ordinal);
+			}
+			catch (ArgumentException)
+			{
+				return false;
+			}
+		}
+
+		private async Task<IActionResult> ProcessImage(string imageName, int? width, int? cropSquare, bool isFallback = false, string? signature = null)
+		{
+			Response.Headers["Content-Signature"] = signature ?? SignatureString;
+
+			var fullPath = ResolveAsset(imageName);
+
+			if (fullPath == null)
+			{
+				if (!isFallback)
+				{
+					var fallback = ResolveAsset(DBConfig.DefaultRoomImage);
+					if (fallback != null)
+					{
+						return await ServeImageFile(fallback, width, cropSquare);
+					}
+				}
+				return NotFound();
+			}
+
+			return await ServeImageFile(fullPath, width, cropSquare);
+		}
+
+		private async Task<IActionResult> ServeImageFile(string fullPath, int? width, int? cropSquare)
+		{
+			if (!width.HasValue)
+			{
+				return PhysicalFile(fullPath, "image/jpeg");
+			}
+
+			Image image;
+			try
+			{
+				image = await Image.LoadAsync(fullPath);
+			}
+			catch (Exception)
+			{
+				return PhysicalFile(fullPath, "image/jpeg");
+			}
+
+			using (image)
+			{
+				if (cropSquare == 1)
+				{
+					int size = Math.Min(image.Width, image.Height);
+
+					var cropRect = new Rectangle((image.Width - size) / 2, (image.Height - size) / 2, size, size);
+
+					image.Mutate(x =>
+					{
+						x.Crop(cropRect);
+						x.Resize(width.Value, width.Value);
+					});
+				}
+				else
+				{
+					image.Mutate(x => x.Resize(width.Value, 0));
+				}
+
+				IImageFormat format = await Image.DetectFormatAsync(fullPath);
+
+				var ms = new MemoryStream();
+
+				await image.SaveAsync(ms, format);
+
+				ms.Position = 0;
+
+				return File(ms, format.DefaultMimeType);
+			}
+		}
+	}
+}