diff options
Diffstat (limited to 'Timeline/Services/UserAvatarService.cs')
| -rw-r--r-- | Timeline/Services/UserAvatarService.cs | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/Timeline/Services/UserAvatarService.cs b/Timeline/Services/UserAvatarService.cs new file mode 100644 index 00000000..dd0e5e7c --- /dev/null +++ b/Timeline/Services/UserAvatarService.cs @@ -0,0 +1,250 @@ +using Microsoft.AspNetCore.Hosting;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.Formats;
+using System;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using Timeline.Entities;
+
+namespace Timeline.Services
+{
+ public class Avatar
+ {
+ public string Type { get; set; }
+ public byte[] Data { get; set; }
+ }
+
+ /// <summary>
+ /// Thrown when avatar is of bad format.
+ /// </summary>
+ [Serializable]
+ public class AvatarDataException : Exception
+ {
+ public enum ErrorReason
+ {
+ /// <summary>
+ /// Decoding image failed.
+ /// </summary>
+ CantDecode,
+ /// <summary>
+ /// Decoding succeeded but the real type is not the specified type.
+ /// </summary>
+ UnmatchedFormat,
+ /// <summary>
+ /// Image is not a square.
+ /// </summary>
+ BadSize
+ }
+
+ public AvatarDataException(Avatar avatar, ErrorReason error, string message) : base(message) { Avatar = avatar; Error = error; }
+ public AvatarDataException(Avatar avatar, ErrorReason error, string message, Exception inner) : base(message, inner) { Avatar = avatar; Error = error; }
+ protected AvatarDataException(
+ System.Runtime.Serialization.SerializationInfo info,
+ System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+
+ public ErrorReason Error { get; set; }
+ public Avatar Avatar { get; set; }
+ }
+
+ /// <summary>
+ /// Provider for default user avatar.
+ /// </summary>
+ /// <remarks>
+ /// Mainly for unit tests.
+ /// </remarks>
+ public interface IDefaultUserAvatarProvider
+ {
+ /// <summary>
+ /// Get the default avatar.
+ /// </summary>
+ Task<Avatar> GetDefaultAvatar();
+ }
+
+ public interface IUserAvatarValidator
+ {
+ /// <summary>
+ /// Validate a avatar's format and size info.
+ /// </summary>
+ /// <param name="avatar">The avatar to validate.</param>
+ /// <exception cref="AvatarDataException">Thrown when validation failed.</exception>
+ Task Validate(Avatar avatar);
+ }
+
+ public interface IUserAvatarService
+ {
+ /// <summary>
+ /// Get avatar of a user. If the user has no avatar, a default one is returned.
+ /// </summary>
+ /// <param name="username">The username of the user to get avatar of.</param>
+ /// <returns>The avatar.</returns>
+ /// <exception cref="ArgumentException">Thrown if <paramref name="username"/> is null or empty.</exception>
+ /// <exception cref="UserNotExistException">Thrown if the user does not exist.</exception>
+ Task<Avatar> GetAvatar(string username);
+
+ /// <summary>
+ /// Set avatar for a user.
+ /// </summary>
+ /// <param name="username">The username of the user to set avatar for.</param>
+ /// <param name="avatar">The avatar. Can be null to delete the saved avatar.</param>
+ /// <exception cref="ArgumentException">Throw if <paramref name="username"/> is null or empty.
+ /// Or thrown if <paramref name="avatar"/> is not null but <see cref="Avatar.Type"/> is null or empty or <see cref="Avatar.Data"/> is null.</exception>
+ /// <exception cref="UserNotExistException">Thrown if the user does not exist.</exception>
+ /// <exception cref="AvatarDataException">Thrown if avatar is of bad format.</exception>
+ Task SetAvatar(string username, Avatar avatar);
+ }
+
+ public class DefaultUserAvatarProvider : IDefaultUserAvatarProvider
+ {
+ private readonly IHostingEnvironment _environment;
+
+ public DefaultUserAvatarProvider(IHostingEnvironment environment)
+ {
+ _environment = environment;
+ }
+
+ public async Task<Avatar> GetDefaultAvatar()
+ {
+ return new Avatar
+ {
+ Type = "image/png",
+ Data = await File.ReadAllBytesAsync(Path.Combine(_environment.ContentRootPath, "default-avatar.png"))
+ };
+ }
+ }
+
+ public class UserAvatarValidator : IUserAvatarValidator
+ {
+ public Task Validate(Avatar avatar)
+ {
+ return Task.Run(() =>
+ {
+ try
+ {
+ using (var image = Image.Load(avatar.Data, out IImageFormat format))
+ {
+ if (!format.MimeTypes.Contains(avatar.Type))
+ throw new AvatarDataException(avatar, AvatarDataException.ErrorReason.UnmatchedFormat, "Image's actual mime type is not the specified one.");
+ if (image.Width != image.Height)
+ throw new AvatarDataException(avatar, AvatarDataException.ErrorReason.BadSize, "Image is not a square, aka, width is not equal to height.");
+ }
+ }
+ catch (UnknownImageFormatException e)
+ {
+ throw new AvatarDataException(avatar, AvatarDataException.ErrorReason.CantDecode, "Failed to decode image. See inner exception.", e);
+ }
+ });
+ }
+ }
+
+ public class UserAvatarService : IUserAvatarService
+ {
+
+ private readonly ILogger<UserAvatarService> _logger;
+
+ private readonly DatabaseContext _database;
+
+ private readonly IDefaultUserAvatarProvider _defaultUserAvatarProvider;
+ private readonly IUserAvatarValidator _avatarValidator;
+
+ public UserAvatarService(ILogger<UserAvatarService> logger, DatabaseContext database, IDefaultUserAvatarProvider defaultUserAvatarProvider, IUserAvatarValidator avatarValidator)
+ {
+ _logger = logger;
+ _database = database;
+ _defaultUserAvatarProvider = defaultUserAvatarProvider;
+ _avatarValidator = avatarValidator;
+ }
+
+ public async Task<Avatar> GetAvatar(string username)
+ {
+ if (string.IsNullOrEmpty(username))
+ throw new ArgumentException("Username is null or empty.", nameof(username));
+
+ var user = await _database.Users.Where(u => u.Name == username).SingleOrDefaultAsync();
+ if (user == null)
+ throw new UserNotExistException(username);
+
+ await _database.Entry(user).Reference(u => u.Avatar).LoadAsync();
+ var avatar = user.Avatar;
+
+ if (avatar == null)
+ {
+ return await _defaultUserAvatarProvider.GetDefaultAvatar();
+ }
+ else
+ {
+ return new Avatar
+ {
+ Type = avatar.Type,
+ Data = avatar.Data
+ };
+ }
+ }
+
+ public async Task SetAvatar(string username, Avatar avatar)
+ {
+ if (string.IsNullOrEmpty(username))
+ throw new ArgumentException("Username is null or empty.", nameof(username));
+
+ if (avatar != null)
+ {
+ if (string.IsNullOrEmpty(avatar.Type))
+ throw new ArgumentException("Type of avatar is null or empty.", nameof(avatar));
+ if (avatar.Data == null)
+ throw new ArgumentException("Data of avatar is null.", nameof(avatar));
+ }
+
+ var user = await _database.Users.Where(u => u.Name == username).SingleOrDefaultAsync();
+ if (user == null)
+ throw new UserNotExistException(username);
+
+ await _database.Entry(user).Reference(u => u.Avatar).LoadAsync();
+ var avatarEntity = user.Avatar;
+
+ if (avatar == null)
+ {
+ if (avatarEntity == null)
+ return;
+ else
+ {
+ _database.UserAvatars.Remove(avatarEntity);
+ await _database.SaveChangesAsync();
+ _logger.LogInformation("Removed an entry in user_avatars.");
+ }
+ }
+ else
+ {
+ await _avatarValidator.Validate(avatar);
+
+ if (avatarEntity == null)
+ {
+ user.Avatar = new UserAvatar
+ {
+ Type = avatar.Type,
+ Data = avatar.Data
+ };
+ }
+ else
+ {
+ avatarEntity.Type = avatar.Type;
+ avatarEntity.Data = avatar.Data;
+ }
+ await _database.SaveChangesAsync();
+ _logger.LogInformation("Added or modified an entry in user_avatars.");
+ }
+ }
+ }
+
+ public static class UserAvatarServiceCollectionExtensions
+ {
+ public static void AddUserAvatarService(this IServiceCollection services)
+ {
+ services.AddScoped<IUserAvatarService, UserAvatarService>();
+ services.AddSingleton<IDefaultUserAvatarProvider, DefaultUserAvatarProvider>();
+ services.AddSingleton<IUserAvatarValidator, UserAvatarValidator>();
+ }
+ }
+}
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