feat: add support for external avatar hosting service (#614)

PluralKit.Bot/BotConfig.cs

@@ -25,6 +25,7 @@ public class BotConfig
     public string? RedisGatewayUrl { get; set; }
 
     public string? DiscordBaseUrl { get; set; }
+    public string? AvatarServiceUrl { get; set; }
 
     public bool DisableErrorReporting { get; set; } = false;
 

PluralKit.Bot/Commands/Groups.cs

@@ -21,13 +21,15 @@ public class Groups
     private readonly HttpClient _client;
     private readonly DispatchService _dispatch;
     private readonly EmbedService _embeds;
+    private readonly AvatarHostingService _avatarHosting;
 
     public Groups(EmbedService embeds, HttpClient client,
-                  DispatchService dispatch)
+                  DispatchService dispatch, AvatarHostingService avatarHosting)
     {
         _embeds = embeds;
         _client = client;
         _dispatch = dispatch;
+        _avatarHosting = avatarHosting;
     }
 
     public async Task CreateGroup(Context ctx)
@@ -261,6 +263,7 @@ public class Groups
         {
             ctx.CheckOwnGroup(target);
 
+            img = await _avatarHosting.TryRehostImage(img, AvatarHostingService.RehostedImageType.Avatar, ctx.Author.Id);
             await AvatarUtils.VerifyAvatarOrThrow(_client, img.Url);
 
             await ctx.Repository.UpdateGroup(target.Id, new GroupPatch { Icon = img.CleanUrl ?? img.Url });
@@ -326,6 +329,7 @@ public class Groups
         {
             ctx.CheckOwnGroup(target);
 
+            img = await _avatarHosting.TryRehostImage(img, AvatarHostingService.RehostedImageType.Banner, ctx.Author.Id);
             await AvatarUtils.VerifyAvatarOrThrow(_client, img.Url, true);
 
             await ctx.Repository.UpdateGroup(target.Id, new GroupPatch { BannerImage = img.CleanUrl ?? img.Url });

PluralKit.Bot/Commands/Member.cs

@@ -16,13 +16,15 @@ public class Member
     private readonly HttpClient _client;
     private readonly DispatchService _dispatch;
     private readonly EmbedService _embeds;
+    private readonly AvatarHostingService _avatarHosting;
 
     public Member(EmbedService embeds, HttpClient client,
-                  DispatchService dispatch)
+                  DispatchService dispatch, AvatarHostingService avatarHosting)
     {
         _embeds = embeds;
         _client = client;
         _dispatch = dispatch;
+        _avatarHosting = avatarHosting;
     }
 
     public async Task NewMember(Context ctx)
@@ -78,6 +80,8 @@ public class Member
                 uriBuilder.Query = "";
                 img.CleanUrl = uriBuilder.Uri.AbsoluteUri;
 
+                img = await _avatarHosting.TryRehostImage(img, AvatarHostingService.RehostedImageType.Avatar, ctx.Author.Id);
+
                 await AvatarUtils.VerifyAvatarOrThrow(_client, img.Url);
                 await ctx.Repository.UpdateMember(member.Id, new MemberPatch { AvatarUrl = img.CleanUrl ?? img.Url }, conn);
 

PluralKit.Bot/Commands/MemberAvatar.cs

@@ -9,10 +9,12 @@ namespace PluralKit.Bot;
 public class MemberAvatar
 {
     private readonly HttpClient _client;
+    private readonly AvatarHostingService _avatarHosting;
 
-    public MemberAvatar(HttpClient client)
+    public MemberAvatar(HttpClient client, AvatarHostingService avatarHosting)
     {
         _client = client;
+        _avatarHosting = avatarHosting;
     }
 
     private async Task AvatarClear(MemberAvatarLocation location, Context ctx, PKMember target, MemberGuildSettings? mgs)
@@ -138,6 +140,8 @@ public class MemberAvatar
         }
 
         ctx.CheckSystem().CheckOwnMember(target);
+
+        avatarArg = await _avatarHosting.TryRehostImage(avatarArg.Value, AvatarHostingService.RehostedImageType.Avatar, ctx.Author.Id);
         await AvatarUtils.VerifyAvatarOrThrow(_client, avatarArg.Value.Url);
         await UpdateAvatar(location, ctx, target, avatarArg.Value.CleanUrl ?? avatarArg.Value.Url);
         await PrintResponse(location, ctx, target, avatarArg.Value, guildData);

PluralKit.Bot/Commands/MemberEdit.cs

@@ -13,10 +13,12 @@ namespace PluralKit.Bot;
 public class MemberEdit
 {
     private readonly HttpClient _client;
+    private readonly AvatarHostingService _avatarHosting;
 
-    public MemberEdit(HttpClient client)
+    public MemberEdit(HttpClient client, AvatarHostingService avatarHosting)
     {
         _client = client;
+        _avatarHosting = avatarHosting;
     }
 
     public async Task Name(Context ctx, PKMember target)
@@ -180,6 +182,7 @@ public class MemberEdit
 
         async Task SetBannerImage(ParsedImage img)
         {
+            img = await _avatarHosting.TryRehostImage(img, AvatarHostingService.RehostedImageType.Banner, ctx.Author.Id);
             await AvatarUtils.VerifyAvatarOrThrow(_client, img.Url, true);
 
             await ctx.Repository.UpdateMember(target.Id, new MemberPatch { BannerImage = img.CleanUrl ?? img.Url });

PluralKit.Bot/Commands/SystemEdit.cs

@@ -18,12 +18,14 @@ public class SystemEdit
     private readonly HttpClient _client;
     private readonly DataFileService _dataFiles;
     private readonly PrivateChannelService _dmCache;
+    private readonly AvatarHostingService _avatarHosting;
 
-    public SystemEdit(DataFileService dataFiles, HttpClient client, PrivateChannelService dmCache)
+    public SystemEdit(DataFileService dataFiles, HttpClient client, PrivateChannelService dmCache, AvatarHostingService avatarHosting)
     {
         _dataFiles = dataFiles;
         _client = client;
         _dmCache = dmCache;
+        _avatarHosting = avatarHosting;
     }
 
     public async Task Name(Context ctx, PKSystem target)
@@ -473,6 +475,7 @@ public class SystemEdit
         {
             ctx.CheckOwnSystem(target);
 
+            img = await _avatarHosting.TryRehostImage(img, AvatarHostingService.RehostedImageType.Avatar, ctx.Author.Id);
             await AvatarUtils.VerifyAvatarOrThrow(_client, img.Url);
 
             await ctx.Repository.UpdateSystem(target.Id, new SystemPatch { AvatarUrl = img.CleanUrl ?? img.Url });
@@ -541,6 +544,7 @@ public class SystemEdit
         {
             ctx.CheckOwnSystem(target);
 
+            img = await _avatarHosting.TryRehostImage(img, AvatarHostingService.RehostedImageType.Avatar, ctx.Author.Id);
             await AvatarUtils.VerifyAvatarOrThrow(_client, img.Url);
 
             await ctx.Repository.UpdateSystemGuild(target.Id, ctx.Guild.Id, new SystemGuildPatch { AvatarUrl = img.CleanUrl ?? img.Url });
@@ -638,6 +642,7 @@ public class SystemEdit
 
         else if (await ctx.MatchImage() is { } img)
         {
+            img = await _avatarHosting.TryRehostImage(img, AvatarHostingService.RehostedImageType.Banner, ctx.Author.Id);
             await AvatarUtils.VerifyAvatarOrThrow(_client, img.Url, true);
 
             await ctx.Repository.UpdateSystem(target.Id, new SystemPatch { BannerImage = img.CleanUrl ?? img.Url });

PluralKit.Bot/Modules.cs

@@ -136,6 +136,7 @@ public class BotModule: Module
         builder.RegisterType<ErrorMessageService>().AsSelf().SingleInstance();
         builder.RegisterType<CommandMessageService>().AsSelf().SingleInstance();
         builder.RegisterType<InteractionDispatchService>().AsSelf().SingleInstance();
+        builder.RegisterType<AvatarHostingService>().AsSelf().SingleInstance();
 
         // Sentry stuff
         builder.Register(_ => new Scope(null)).AsSelf().InstancePerLifetimeScope();

PluralKit.Bot/Services/AvatarHostingService.cs

@@ -0,0 +1,65 @@
+using System.Net;
+using System.Net.Http.Json;
+
+namespace PluralKit.Bot;
+
+public class AvatarHostingService
+{
+    private readonly BotConfig _config;
+    private readonly HttpClient _client;
+
+    public AvatarHostingService(BotConfig config, HttpClient client)
+    {
+        _config = config;
+        _client = client;
+    }
+
+    public async Task<ParsedImage> TryRehostImage(ParsedImage input, RehostedImageType type, ulong userId)
+    {
+        var uploaded = await TryUploadAvatar(input.Url, type, userId);
+        if (uploaded != null)
+        {
+            // todo: make new image type called Cdn?
+            return new ParsedImage { Url = uploaded, Source = AvatarSource.Url };
+        }
+
+        return input;
+    }
+
+    public async Task<string?> TryUploadAvatar(string? avatarUrl, RehostedImageType type, ulong userId)
+    {
+        if (!AvatarUtils.IsDiscordCdnUrl(avatarUrl))
+            return null;
+
+        if (_config.AvatarServiceUrl == null)
+            return null;
+
+        var kind = type switch
+        {
+            RehostedImageType.Avatar => "avatar",
+            RehostedImageType.Banner => "banner",
+            _ => throw new ArgumentOutOfRangeException(nameof(type), type, null)
+        };
+
+        var response = await _client.PostAsJsonAsync(_config.AvatarServiceUrl + "/pull",
+            new { url = avatarUrl, kind, uploaded_by = userId });
+        if (response.StatusCode != HttpStatusCode.OK)
+        {
+            var error = await response.Content.ReadFromJsonAsync<ErrorResponse>();
+            throw new PKError($"Error uploading image to CDN: {error.Error}");
+        }
+
+        var success = await response.Content.ReadFromJsonAsync<SuccessResponse>();
+        return success.Url;
+    }
+
+    public record ErrorResponse(string Error);
+
+    public record SuccessResponse(string Url, bool New);
+
+    public enum RehostedImageType
+    {
+        Avatar,
+        Banner,
+    }
+}

PluralKit.Bot/Utils/AvatarUtils.cs

@@ -80,4 +80,6 @@ public static class AvatarUtils
 
         return newUrl;
     }
+
+    public static bool IsDiscordCdnUrl(string? url) => url != null && DiscordCdnUrl.Match(url).Success;
 }