Show a user's avatar on the public profile (#333)

web/backend/Features/Features.Users/Dtos/UserDtoMapper.cs

@@ -1,19 +1,39 @@
 using Domain.Entities;
+using Features.ImageUploads.Services;
 
 namespace Features.Users.Dtos;
 
 /// <summary>Converts user domain entities into API response models.</summary>
 public static class UserDtoMapper
 {
+    /// <summary>
+    ///     How long a presigned avatar URL stays valid. Long enough to outlive the page that embeds it,
+    ///     short enough that a leaked URL stops working.
+    /// </summary>
+    public static readonly TimeSpan AvatarUrlLifetime = TimeSpan.FromHours(1);
+
     /// <summary>Converts a user account into its public-profile representation.</summary>
-    public static PublicUserProfileDto ToPublicProfileDto(this UserAccount user)
+    /// <param name="user">The account to convert.</param>
+    /// <param name="fileStorageProvider">
+    ///     Signs the download URL for the account's avatar. <c>Photo.Hyperlink</c> holds an object key
+    ///     rather than a URL, so it has to be signed before a client can fetch it.
+    /// </param>
+    public static PublicUserProfileDto ToPublicProfileDto(
+        this UserAccount user,
+        IFileStorageProvider fileStorageProvider
+    )
     {
+        string? avatarKey = user.UserAvatar?.Photo?.Hyperlink;
+
         return new PublicUserProfileDto(
             UserAccountId : user.UserAccountId,
             Username : user.Username,
             FirstName : user.FirstName,
             LastName : user.LastName,
             Biography : user.UserProfile?.Biography ?? string.Empty,
+            AvatarUrl : string.IsNullOrWhiteSpace(avatarKey)
+                ? string.Empty
+                : fileStorageProvider.GetPresignedUrl(avatarKey, AvatarUrlLifetime),
             CreatedAt : user.CreatedAt
         );
     }

web/backend/Features/Features.Users/Dtos/UserDtos.cs

@@ -7,5 +7,6 @@ public record PublicUserProfileDto(
     string FirstName,
     string LastName,
     string Biography,
+    string AvatarUrl,
     DateTime CreatedAt
 );

web/backend/Features/Features.Users/Queries/GetAllUsers/GetAllUsersHandler.cs

@@ -1,12 +1,15 @@
 using Domain.Entities;
+using Features.ImageUploads.Services;
 using Features.Users.Dtos;
 using Features.Users.Repository;
 using MediatR;
 
 namespace Features.Users.Queries.GetAllUsers;
 
-public class GetAllUsersHandler(IUserListRepository repository)
-    : IRequestHandler<GetAllUsersQuery, IEnumerable<PublicUserProfileDto>>
+public class GetAllUsersHandler(
+    IUserListRepository repository,
+    IFileStorageProvider fileStorageProvider
+) : IRequestHandler<GetAllUsersQuery, IEnumerable<PublicUserProfileDto>>
 {
     public async Task<IEnumerable<PublicUserProfileDto>> Handle(
         GetAllUsersQuery request,
@@ -14,6 +17,6 @@ public class GetAllUsersHandler(IUserListRepository repository)
     )
     {
         IEnumerable<UserAccount> users = await repository.GetAllAsync(request.Limit, request.Offset);
-        return users.Select(user => user.ToPublicProfileDto());
+        return users.Select(user => user.ToPublicProfileDto(fileStorageProvider));
     }
 }

web/backend/Features/Features.Users/Queries/GetPublicUserProfileById/GetPublicUserProfileByIdHandler.cs

@@ -1,13 +1,16 @@
 using Domain.Entities;
 using Domain.Exceptions;
+using Features.ImageUploads.Services;
 using Features.Users.Dtos;
 using Features.Users.Repository;
 using MediatR;
 
 namespace Features.Users.Queries.GetPublicUserProfileById;
 
-public class GetPublicUserProfileByIdHandler(IUserListRepository repository)
-    : IRequestHandler<GetPublicUserProfileByIdQuery, PublicUserProfileDto>
+public class GetPublicUserProfileByIdHandler(
+    IUserListRepository repository,
+    IFileStorageProvider fileStorageProvider
+) : IRequestHandler<GetPublicUserProfileByIdQuery, PublicUserProfileDto>
 {
     /// <exception cref="NotFoundException">Thrown when no user account exists with the given ID.</exception>
     public async Task<PublicUserProfileDto> Handle(
@@ -18,6 +21,6 @@ public class GetPublicUserProfileByIdHandler(IUserListRepository repository)
         UserAccount? user = await repository.GetByIdAsync(request.UserAccountId);
         if (user is null)
             throw new NotFoundException($"User with ID {request.UserAccountId} not found");
-        return user.ToPublicProfileDto();
+        return user.ToPublicProfileDto(fileStorageProvider);
     }
 }

web/backend/Features/Features.Users/Repository/UserListRepository.cs

@@ -15,7 +15,10 @@ public class UserListRepository(ISqlConnectionFactory connectionFactory)
     /// <inheritdoc />
     /// <remarks>
     ///     Left-joins <c>Social.UserProfile</c>, so <see cref="UserAccount.UserProfile" /> is
-    ///     <c>null</c> for an account whose profile has yet to be created.
+    ///     <c>null</c> for an account whose profile has yet to be created, and left-joins the
+    ///     account's active <c>Social.UserAvatar</c> (<c>ValidTo IS NULL</c>) with its
+    ///     <c>Media.Photo</c>, so <see cref="UserAccount.UserAvatar" /> is <c>null</c> for an account
+    ///     with no avatar.
     /// </remarks>
     public async Task<UserAccount?> GetByIdAsync(Guid id)
     {
@@ -23,51 +26,89 @@ public class UserListRepository(ISqlConnectionFactory connectionFactory)
         IEnumerable<UserAccount> results = await connection.QueryAsync<
             UserAccount,
             UserProfile,
+            Photo,
+            UserAvatar,
             UserAccount
         >(
             """
             SELECT 
-                ua.UserAccountID, 
-                ua.Username, 
-                ua.FirstName, ua.LastName, ua.Email, ua.CreatedAt, ua.UpdatedAt,
-                ua.DateOfBirth, ua.RowVersion,
-                up.UserProfileID, up.UserAccountID, up.Biography, up.RowVersion
+                ua.UserAccountID, ua.Username, ua.FirstName, ua.LastName,
+                ua.Email, ua.CreatedAt, ua.UpdatedAt, ua.DateOfBirth,
+                ua.RowVersion, up.UserProfileID, up.UserAccountID,
+                up.Biography, up.RowVersion, p.PhotoID, p.UploadedByID, 
+                p.Hyperlink, p.UploadedAt, p.RowVersion, av.UserAvatarID, 
+                av.UserProfileID, av.PhotoID, av.ValidFrom, av.ValidTo,
+                av.RowVersion
             FROM Auth.UserAccount ua
-            LEFT JOIN Social.UserProfile up ON ua.UserAccountID = up.UserAccountID
+            LEFT JOIN Social.UserProfile up 
+                ON ua.UserAccountID = up.UserAccountID
+            LEFT JOIN Social.UserAvatar av
+                ON up.UserProfileID = av.UserProfileID 
+                       AND av.ValidTo IS NULL
+            LEFT JOIN Media.Photo p ON av.PhotoID = p.PhotoID
             WHERE ua.UserAccountID = @UserAccountId
             """,
             MapUserRow,
             new { UserAccountId = id },
-            splitOn: "UserProfileID"
+            splitOn: AvatarSplitOn
         );
 
         return results.SingleOrDefault();
     }
 
-    private static UserAccount MapUserRow(UserAccount user, UserProfile? profile)
-    {
-        user.UserProfile = profile;
-        return user;
-    }
-
     /// <inheritdoc />
     /// <remarks>
     ///     Always applies pagination via <c>OFFSET</c>/<c>FETCH</c>, ordered by creation date descending.
     ///     A <c>null</c> <paramref name="limit" />/<paramref name="offset" /> is treated as "no limit"/"no offset".
-    ///     Does not select <c>Email</c> or <c>DateOfBirth</c>: this listing is consumed only as public
-    ///     profiles, so those fields are left at their default rather than read from the database.
+    ///     Joins the same profile and active-avatar rows as <see cref="GetByIdAsync" />, both of which are
+    ///     part of a public profile. Does not select <c>Email</c> or <c>DateOfBirth</c>: this listing is
+    ///     consumed only as public profiles, so those fields are left at their default rather than read
+    ///     from the database.
     /// </remarks>
     public async Task<IEnumerable<UserAccount>> GetAllAsync(int? limit, int? offset)
     {
         await using DbConnection connection = await CreateConnection();
-        return await connection.QueryAsync<UserAccount>(
+        return await connection.QueryAsync<
+            UserAccount,
+            UserProfile,
+            Photo,
+            UserAvatar,
+            UserAccount
+        >(
             """
-            SELECT UserAccountID, Username, FirstName, LastName, CreatedAt, UpdatedAt, RowVersion
-            FROM Auth.UserAccount
-            ORDER BY CreatedAt DESC
+            SELECT
+                ua.UserAccountID, ua.Username, ua.FirstName, ua.LastName,
+                ua.CreatedAt, ua.UpdatedAt, ua.RowVersion,
+                up.UserProfileID, up.UserAccountID, up.Biography, up.RowVersion,
+                p.PhotoID, p.UploadedByID, p.Hyperlink, p.UploadedAt, p.RowVersion,
+                av.UserAvatarID, av.UserProfileID, av.PhotoID, av.ValidFrom, av.ValidTo,
+                av.RowVersion
+            FROM Auth.UserAccount ua
+            LEFT JOIN Social.UserProfile up ON ua.UserAccountID = up.UserAccountID
+            LEFT JOIN Social.UserAvatar av
+                ON up.UserProfileID = av.UserProfileID AND av.ValidTo IS NULL
+            LEFT JOIN Media.Photo p ON av.PhotoID = p.PhotoID
+            ORDER BY ua.CreatedAt DESC
             OFFSET @Offset ROWS FETCH NEXT @Limit ROWS ONLY
             """,
-            new { Offset = offset ?? 0, Limit = limit ?? int.MaxValue }
+            MapUserRow,
+            new { Offset = offset ?? 0, Limit = limit ?? int.MaxValue },
+            splitOn: AvatarSplitOn
         );
     }
+
+    private const string AvatarSplitOn = "UserProfileID,PhotoID,UserAvatarID";
+
+    private static UserAccount MapUserRow(
+        UserAccount user,
+        UserProfile? profile,
+        Photo? photo,
+        UserAvatar? avatar
+    )
+    {
+        user.UserProfile = profile;
+        avatar?.Photo = photo;
+        user.UserAvatar = avatar;
+        return user;
+    }
 }