Release v37.1

Closes #189

app/.idea/.idea.DiscordHistoryTracker/.idea/avalonia.xml

@@ -7,6 +7,7 @@
         <entry key="Desktop/Dialogs/CheckBox/CheckBoxDialog.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Dialogs/Message/MessageDialog.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Dialogs/Progress/ProgressDialog.axaml" value="Desktop/Desktop.csproj" />
+        <entry key="Desktop/Dialogs/TextBox/TextBoxDialog.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/AboutWindow.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/Controls/AttachmentFilterPanel.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/Controls/MessageFilterPanel.axaml" value="Desktop/Desktop.csproj" />

app/Desktop/App.axaml

@@ -7,7 +7,7 @@
     <Application.Styles>
 
         <FluentTheme Mode="Light" />
-        <StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Default.xaml"/>
+        <StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Default.xaml" />
 
         <Style Selector="Button, CheckBox, RadioButton, Expander /template/ ToggleButton#ExpanderHeader">
             <Setter Property="Cursor" Value="Hand" />
@@ -33,8 +33,19 @@
         <Style Selector="TextBox:focus /template/ Border#PART_BorderElement">
             <Setter Property="BorderThickness" Value="1" />
         </Style>
-        <Style Selector="TextBox:disabled"><!-- TODO bug in Avalonia (https://github.com/AvaloniaUI/Avalonia/pull/7792) -->
+        <Style Selector="TextBox:error DataValidationErrors">
-            <Setter Property="Foreground" Value="{DynamicResource TextControlForegroundDisabled}" />
+            <Style.Resources>
+                <ControlTemplate x:Key="InlineDataValidationContentTemplate" TargetType="DataValidationErrors">
+                    <ContentPresenter Name="PART_ContentPresenter"
+                                      Padding="{TemplateBinding Padding}"
+                                      Background="{TemplateBinding Background}"
+                                      BorderThickness="{TemplateBinding BorderThickness}"
+                                      CornerRadius="{TemplateBinding CornerRadius}"
+                                      Content="{TemplateBinding Content}"
+                                      ContentTemplate="{TemplateBinding ContentTemplate}" />
+                </ControlTemplate>
+            </Style.Resources>
+            <Setter Property="Template" Value="{StaticResource InlineDataValidationContentTemplate}" />
         </Style>
 
         <Style Selector="Expander /template/ ToggleButton#ExpanderHeader">

app/Desktop/Common/BytesValueConverter.cs

@@ -4,12 +4,26 @@ using Avalonia.Data.Converters;
 
 namespace DHT.Desktop.Common {
 	sealed class BytesValueConverter : IValueConverter {
-		private static readonly string[] Units = {
+		private sealed class Unit {
-			"B",
+			private readonly string label;
-			"kB",
+			private readonly string numberFormat;
-			"MB",
+			
-			"GB",
+			public Unit(string label, int decimalPlaces) {
-			"TB"
+				this.label = label;
+				this.numberFormat = "{0:n" + decimalPlaces + "}";
+			}
+			
+			public string Format(double size) {
+				return string.Format(Program.Culture, numberFormat, size) + " " + label;
+			}
+		}
+		
+		private static readonly Unit[] Units = {
+			new ("B", decimalPlaces: 0),
+			new ("kB", decimalPlaces: 0),
+			new ("MB", decimalPlaces: 1),
+			new ("GB", decimalPlaces: 1),
+			new ("TB", decimalPlaces: 1)
 		};
 
 		private const int Scale = 1000;
@@ -17,13 +31,7 @@ namespace DHT.Desktop.Common {
 		private static string Convert(ulong size) {
 			int power = size == 0L ? 0 : (int) Math.Log(size, Scale);
 			int unit = power >= Units.Length ? Units.Length - 1 : power;
-			if (unit == 0) {
+			return Units[unit].Format(unit == 0 ? size : size / Math.Pow(Scale, unit));
-				return string.Format(Program.Culture, "{0:n0}", size) + " " + Units[unit];
-			}
-			else {
-				double humanReadableSize = size / Math.Pow(Scale, unit);
-				return string.Format(Program.Culture, "{0:n0}", humanReadableSize) + " " + Units[unit];
-			}
 		}
 
 		public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture) {

app/Desktop/Desktop.csproj

@@ -21,16 +21,20 @@
     <DebugType>none</DebugType>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Avalonia" Version="0.10.14" />
+    <PackageReference Include="Avalonia" Version="0.10.16" />
-    <PackageReference Include="Avalonia.Controls.DataGrid" Version="0.10.14" />
+    <PackageReference Include="Avalonia.Controls.DataGrid" Version="0.10.16" />
-    <PackageReference Include="Avalonia.Desktop" Version="0.10.14" />
+    <PackageReference Include="Avalonia.Desktop" Version="0.10.16" />
-    <PackageReference Include="Avalonia.Diagnostics" Version="0.10.14" Condition=" '$(Configuration)' == 'Debug' " />
+    <PackageReference Include="Avalonia.Diagnostics" Version="0.10.16" Condition=" '$(Configuration)' == 'Debug' " />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Server\Server.csproj" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="..\Version.cs" Link="Version.cs" />
+    <Compile Update="Dialogs\TextBox\TextBoxDialog.axaml.cs">
+      <DependentUpon>CheckBoxDialog.axaml</DependentUpon>
+      <SubType>Code</SubType>
+    </Compile>
   </ItemGroup>
   <ItemGroup>
     <AvaloniaResource Include="Resources/icon.ico" />

app/Desktop/Dialogs/TextBox/TextBoxDialog.axaml

@@ -0,0 +1,56 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        xmlns:namespace="clr-namespace:DHT.Desktop.Dialogs.TextBox"
+        mc:Ignorable="d" d:DesignWidth="500"
+        x:Class="DHT.Desktop.Dialogs.TextBox.TextBoxDialog"
+        Title="{Binding Title}"
+        Icon="avares://DiscordHistoryTracker/Resources/icon.ico"
+        Width="500" SizeToContent="Height" CanResize="False"
+        WindowStartupLocation="CenterOwner">
+
+    <Window.DataContext>
+        <namespace:TextBoxDialogModel />
+    </Window.DataContext>
+
+    <Window.Styles>
+        <Style Selector="Panel.buttons">
+            <Setter Property="Margin" Value="0 20 0 0" />
+        </Style>
+        <Style Selector="Panel.buttons > WrapPanel.right">
+            <Setter Property="HorizontalAlignment" Value="Right" />
+        </Style>
+        <Style Selector="Panel.buttons Button">
+            <Setter Property="MinWidth" Value="80" />
+            <Setter Property="Margin" Value="8 0 0 0" />
+        </Style>
+    </Window.Styles>
+
+    <StackPanel Margin="20">
+        <ScrollViewer MaxHeight="400">
+            <StackPanel Spacing="10">
+                <TextBlock Text="{Binding Description}" TextWrapping="Wrap" />
+                <ItemsRepeater Items="{Binding Items}">
+                    <ItemsRepeater.ItemTemplate>
+                        <DataTemplate>
+                            <DockPanel Margin="0 5 25 0">
+                                <TextBox Name="Input" Text="{Binding Value}" Width="180" VerticalAlignment="Top" DockPanel.Dock="Right" />
+                                <Label Target="Input" VerticalAlignment="Center" DockPanel.Dock="Left">
+                                    <TextBlock Text="{Binding Title}" TextWrapping="Wrap" />
+                                </Label>
+                            </DockPanel>
+                        </DataTemplate>
+                    </ItemsRepeater.ItemTemplate>
+                </ItemsRepeater>
+            </StackPanel>
+        </ScrollViewer>
+        <Panel Classes="buttons">
+            <WrapPanel Classes="right">
+                <Button Click="ClickOk" IsEnabled="{Binding !HasErrors}">OK</Button>
+                <Button Click="ClickCancel">Cancel</Button>
+            </WrapPanel>
+        </Panel>
+    </StackPanel>
+
+</Window>

app/Desktop/Dialogs/TextBox/TextBoxDialog.axaml.cs

@@ -0,0 +1,31 @@
+using System.Diagnostics.CodeAnalysis;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+using Avalonia.Markup.Xaml;
+using DHT.Desktop.Dialogs.Message;
+
+namespace DHT.Desktop.Dialogs.TextBox {
+	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+	public sealed class TextBoxDialog : Window {
+		public TextBoxDialog() {
+			InitializeComponent();
+			#if DEBUG
+			this.AttachDevTools();
+			#endif
+		}
+
+		private void InitializeComponent() {
+			AvaloniaXamlLoader.Load(this);
+		}
+
+		public void ClickOk(object? sender, RoutedEventArgs e) {
+			Close(DialogResult.OkCancel.Ok);
+		}
+
+		public void ClickCancel(object? sender, RoutedEventArgs e) {
+			Close(DialogResult.OkCancel.Cancel);
+		}
+	}
+}
+

app/Desktop/Dialogs/TextBox/TextBoxDialogModel.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using DHT.Utils.Models;
+
+namespace DHT.Desktop.Dialogs.TextBox {
+	class TextBoxDialogModel : BaseModel {
+		public string Title { get; init; } = "";
+		public string Description { get; init; } = "";
+
+		private IReadOnlyList<TextBoxItem> items = Array.Empty<TextBoxItem>();
+
+		public IReadOnlyList<TextBoxItem> Items {
+			get => items;
+
+			protected set {
+				foreach (var item in items) {
+					item.ErrorsChanged -= OnItemErrorsChanged;
+				}
+
+				items = value;
+
+				foreach (var item in items) {
+					item.ErrorsChanged += OnItemErrorsChanged;
+				}
+			}
+		}
+		
+		public bool HasErrors => Items.Any(static item => !item.IsValid);
+
+		private void OnItemErrorsChanged(object? sender, DataErrorsChangedEventArgs e) {
+			OnPropertyChanged(nameof(HasErrors));
+		}
+	}
+
+	sealed class TextBoxDialogModel<T> : TextBoxDialogModel {
+		public new IReadOnlyList<TextBoxItem<T>> Items { get; }
+
+		public IEnumerable<TextBoxItem<T>> ValidItems => Items.Where(static item => item.IsValid);
+
+		public TextBoxDialogModel(IEnumerable<TextBoxItem<T>> items) {
+			this.Items = new List<TextBoxItem<T>>(items);
+			base.Items = this.Items;
+		}
+	}
+}

app/Desktop/Dialogs/TextBox/TextBoxItem.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Collections;
+using System.ComponentModel;
+using DHT.Utils.Models;
+
+namespace DHT.Desktop.Dialogs.TextBox {
+	class TextBoxItem : BaseModel, INotifyDataErrorInfo {
+		public string Title { get; init; } = "";
+		public object? Item { get; init; } = null;
+		
+		public Func<string, bool> ValidityCheck { get; init; } = static _ => true;
+		public bool IsValid => ValidityCheck(Value);
+
+		private string value = string.Empty;
+
+		public string Value {
+			get => this.value;
+			set {
+				Change(ref this.value, value);
+				ErrorsChanged?.Invoke(this, new DataErrorsChangedEventArgs(nameof(Value)));
+			}
+		}
+
+		public IEnumerable GetErrors(string? propertyName) {
+			if (propertyName == nameof(Value) && !IsValid) {
+				yield return string.Empty;
+			}
+		}
+
+		public bool HasErrors => !IsValid;
+		public event EventHandler<DataErrorsChangedEventArgs>? ErrorsChanged;
+	}
+
+	sealed class TextBoxItem<T> : TextBoxItem {
+		public new T Item { get; }
+
+		public TextBoxItem(T item) {
+			this.Item = item;
+			base.Item = item;
+		}
+	}
+}

app/Desktop/Main/Controls/AttachmentFilterPanelModel.cs

@@ -9,7 +9,7 @@ using DHT.Utils.Tasks;
 
 namespace DHT.Desktop.Main.Controls {
 	sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
-		public sealed record Unit(string Name, int Scale);
+		public sealed record Unit(string Name, uint Scale);
 
 		private static readonly Unit[] AllUnits = {
 			new ("B", 1),
@@ -26,7 +26,7 @@ namespace DHT.Desktop.Main.Controls {
 		public string FilterStatisticsText { get; private set; } = "";
 
 		private bool limitSize = false;
-		private int maximumSize = 0;
+		private ulong maximumSize = 0L;
 		private Unit maximumSizeUnit = AllUnits[0];
 
 		public bool LimitSize {
@@ -34,7 +34,7 @@ namespace DHT.Desktop.Main.Controls {
 			set => Change(ref limitSize, value);
 		}
 
-		public int MaximumSize {
+		public ulong MaximumSize {
 			get => maximumSize;
 			set => Change(ref maximumSize, value);
 		}
@@ -116,7 +116,11 @@ namespace DHT.Desktop.Main.Controls {
 			AttachmentFilter filter = new();
 
 			if (LimitSize) {
+				try {
 					filter.MaxBytes = maximumSize * maximumSizeUnit.Scale;
+				} catch (ArithmeticException) {
+					// set no size limit, because the overflown size is larger than any file could possibly be
+				}
 			}
 
 			return filter;

app/Desktop/Main/Controls/MessageFilterPanelModel.cs

@@ -169,7 +169,7 @@ namespace DHT.Desktop.Main.Controls {
 			var exportedMessageCountStr = exportedMessageCount?.Format() ?? "(...)";
 			var totalMessageCountStr = totalMessageCount?.Format() ?? "(...)";
 			
-			FilterStatisticsText = verb + " " + exportedMessageCountStr + " out of " + totalMessageCountStr + " message" + (totalMessageCount is null or 0 ? "." : "s.");
+			FilterStatisticsText = verb + " " + exportedMessageCountStr + " out of " + totalMessageCountStr + " message" + (totalMessageCount is null or 1 ? "." : "s.");
 			OnPropertyChanged(nameof(FilterStatisticsText));
 		}
 

app/Desktop/Main/Pages/AttachmentsPageModel.cs

@@ -175,7 +175,6 @@ namespace DHT.Desktop.Main.Pages {
 			};
 
 			db.RemoveDownloadItems(allExceptFailedFilter, FilterRemovalMode.KeepMatching);
-			downloadStatisticsComputer.Recompute();
 
 			if (IsDownloading) {
 				EnqueueDownloadItems();

app/Desktop/Main/Pages/DatabasePage.axaml

@@ -24,6 +24,7 @@
         <WrapPanel>
             <Button Command="{Binding OpenDatabaseFolder}">Open Database Folder</Button>
             <Button Command="{Binding MergeWithDatabase}">Merge with Database(s)...</Button>
+            <Button Command="{Binding ImportLegacyArchive}">Import Legacy Archive(s)...</Button>
         </WrapPanel>
     </StackPanel>
 

app/Desktop/Main/Pages/DatabasePageModel.cs

@@ -1,6 +1,8 @@
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
@@ -9,7 +11,10 @@ using Avalonia.Threading;
 using DHT.Desktop.Common;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Dialogs.Progress;
+using DHT.Desktop.Dialogs.TextBox;
+using DHT.Server.Data;
 using DHT.Server.Database;
+using DHT.Server.Database.Import;
 using DHT.Utils.Logging;
 using DHT.Utils.Models;
 
@@ -112,6 +117,73 @@ namespace DHT.Desktop.Main.Pages {
 			});
 		}
 
+		public async void ImportLegacyArchive() {
+			var fileDialog = new OpenFileDialog {
+				Title = "Open Legacy DHT Archive",
+				Directory = Path.GetDirectoryName(Db.Path),
+				AllowMultiple = true
+			};
+
+			string[]? paths = await fileDialog.ShowAsync(window);
+			if (paths == null || paths.Length == 0) {
+				return;
+			}
+
+			ProgressDialog progressDialog = new ProgressDialog();
+			progressDialog.DataContext = new ProgressDialogModel(async callback => await ImportLegacyArchiveFromPaths(Db, paths, progressDialog, callback)) {
+				Title = "Legacy Archive Import"
+			};
+
+			await progressDialog.ShowDialog(window);
+		}
+
+		private static async Task ImportLegacyArchiveFromPaths(IDatabaseFile target, string[] paths, ProgressDialog dialog, IProgressCallback callback) {
+			var fakeSnowflake = new FakeSnowflake();
+
+			await PerformImport(target, paths, dialog, callback, "Legacy Archive Import", "Legacy Archive Error", "archive file", async path => {
+				await using var jsonStream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read);
+				
+				return await LegacyArchiveImport.Read(jsonStream, target, fakeSnowflake, async servers => {
+					SynchronizationContext? prevSyncContext = SynchronizationContext.Current;
+					SynchronizationContext.SetSynchronizationContext(new AvaloniaSynchronizationContext());
+					Dictionary<DHT.Server.Data.Server, ulong>? result = await Dispatcher.UIThread.InvokeAsync(() => AskForServerIds(dialog, servers));
+					SynchronizationContext.SetSynchronizationContext(prevSyncContext);
+					return result;
+				});
+			});
+		}
+
+		private static async Task<Dictionary<DHT.Server.Data.Server, ulong>?> AskForServerIds(Window window, DHT.Server.Data.Server[] servers) {
+			static bool IsValidSnowflake(string value) {
+				return string.IsNullOrEmpty(value) || ulong.TryParse(value, out _);
+			}
+			
+			var items = new List<TextBoxItem<DHT.Server.Data.Server>>();
+
+			foreach (var server in servers.OrderBy(static server => server.Type).ThenBy(static server => server.Name)) {
+				items.Add(new TextBoxItem<DHT.Server.Data.Server>(server) {
+					Title = server.Name + " (" + ServerTypes.ToNiceString(server.Type) + ")",
+					ValidityCheck = IsValidSnowflake
+				});
+			}
+
+			var model = new TextBoxDialogModel<DHT.Server.Data.Server>(items) {
+				Title = "Imported Server IDs",
+				Description = "Please fill in the IDs of servers and direct messages. First enable Developer Mode in Discord, then right-click each server or direct message, click 'Copy ID', and paste it into the input field. If a server no longer exists, leave its input field empty to use a random ID."
+			};
+
+			var dialog = new TextBoxDialog { DataContext = model };
+			var result = await dialog.ShowDialog<DialogResult.OkCancel>(window);
+
+			if (result != DialogResult.OkCancel.Ok) {
+				return null;
+			}
+
+			return model.ValidItems
+			            .Where(static item => !string.IsNullOrEmpty(item.Value))
+			            .ToDictionary(static item => item.Item, static item => ulong.Parse(item.Value));
+		}
+
 		private static async Task PerformImport(IDatabaseFile target, string[] paths, ProgressDialog dialog, IProgressCallback callback, string neutralDialogTitle, string errorDialogTitle, string itemName, Func<string, Task<bool>> performImport) {
 			int total = paths.Length;
 			var oldStatistics = target.SnapshotStatistics();

app/Desktop/Main/Pages/ViewerPageModel.cs

@@ -11,9 +11,11 @@ using Avalonia.Controls;
 using DHT.Desktop.Common;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Main.Controls;
+using DHT.Desktop.Server;
 using DHT.Server.Data.Filters;
 using DHT.Server.Database;
 using DHT.Server.Database.Export;
+using DHT.Server.Database.Export.Strategy;
 using DHT.Utils.Models;
 using static DHT.Desktop.Program;
 
@@ -55,7 +57,7 @@ namespace DHT.Desktop.Main.Pages {
 			HasFilters = FilterModel.HasAnyFilters;
 		}
 
-		private async Task WriteViewerFile(string path) {
+		private async Task WriteViewerFile(string path, IViewerExportStrategy strategy) {
 			const string ArchiveTag = "/*[ARCHIVE]*/";
 
 			string indexFile = await Resources.ReadTextAsync("Viewer/index.html");
@@ -68,7 +70,7 @@ namespace DHT.Desktop.Main.Pages {
 			string jsonTempFile = path + ".tmp";
 
 			await using (var jsonStream = new FileStream(jsonTempFile, FileMode.Create, FileAccess.ReadWrite, FileShare.Read)) {
-				await ViewerJsonExport.Generate(jsonStream, db, FilterModel.CreateFilter());
+				await ViewerJsonExport.Generate(jsonStream, strategy, db, FilterModel.CreateFilter());
 
 				char[] jsonBuffer = new char[Math.Min(32768, jsonStream.Position)];
 				jsonStream.Position = 0;
@@ -106,7 +108,7 @@ namespace DHT.Desktop.Main.Pages {
 			TemporaryFiles.Add(fullPath);
 			
 			Directory.CreateDirectory(rootPath);
-			await WriteViewerFile(fullPath);
+			await WriteViewerFile(fullPath, new LiveViewerExportStrategy(ServerManager.Port, ServerManager.Token));
 
 			Process.Start(new ProcessStartInfo(fullPath) { UseShellExecute = true });
 		}
@@ -126,7 +128,7 @@ namespace DHT.Desktop.Main.Pages {
 
 			string? path = await dialog;
 			if (!string.IsNullOrEmpty(path)) {
-				await WriteViewerFile(path);
+				await WriteViewerFile(path, StandaloneViewerExportStrategy.Instance);
 			}
 		}
 

app/Resources/Tracker/scripts/discord.js

@@ -91,13 +91,15 @@ class DISCORD {
 	static getMessageElementProps(ele) {
 		const props = DOM.getReactProps(ele);
 		
-		if (props.children && props.children.length >= 4) {
+		if (props.children && props.children.length) {
-			const childProps = props.children[3].props;
+			for (let i = 3; i < props.children.length; i++) {
+				const childProps = props.children[i].props;
 				
-			if ("message" in childProps && "channel" in childProps) {
+				if (childProps && "message" in childProps && "channel" in childProps) {
 					return childProps;
 				}
 			}
+		}
 		
 		return null;
 	}
@@ -110,16 +112,20 @@ class DISCORD {
 			const messages = [];
 			
 			for (const ele of this.getMessageElements()) {
+				try {
 					const props = this.getMessageElementProps(ele);
 					
 					if (props != null) {
 						messages.push(props.message);
 					}
+				} catch (e) {
+					console.error("[DHT] Error extracing message data, skipping it.", e, ele, DOM.tryGetReactProps(ele));
+				}
 			}
 			
 			return messages;
 		} catch (e) {
-			console.error(e);
+			console.error("[DHT] Error retrieving messages.", e);
 			return [];
 		}
 	}

app/Resources/Tracker/scripts/dom.js

@@ -71,4 +71,15 @@ class DOM {
 		key = keys.find(key => key.startsWith("__reactProps$"));
 		return key ? ele[key] : null;
 	}
+	
+	/**
+	 * Returns internal React state object of an element, or null if the retrieval throws.
+	 */
+	static tryGetReactProps(ele) {
+		try {
+			return this.getReactProps(ele);
+		} catch (e) {
+			return null;
+		}
+	}
 }

app/Resources/Tracker/scripts/state.js

@@ -251,6 +251,11 @@ const STATE = (function() {
 							mapped.type = attachment.content_type;
 						}
 						
+						if (attachment.width && attachment.height) {
+							mapped.width = attachment.width;
+							mapped.height = attachment.height;
+						}
+						
 						return mapped;
 					});
 				}

app/Resources/Tracker/styles/controller.css

@@ -1,9 +1,5 @@
-#app-mount div[class*="app-"] {
+#app-mount {
-  margin-bottom: 48px !important;
+  height: calc(100% - 48px) !important;
-}
-
-#app-mount div[class*="app-"] > div[class*="app-"] {
-  margin-bottom: 0 !important;
 }
 
 #dht-ctrl {

app/Resources/Viewer/scripts/discord.js

@@ -1,7 +1,7 @@
 const DISCORD = (function() {
 	const regex = {
 		formatBold: /\*\*([\s\S]+?)\*\*(?!\*)/g,
-		formatItalic: /(.)?\*([\s\S]+?)\*(?!\*)/g,
+		formatItalic: /(.)?([_*])([\s\S]+?)\2(?!\2)/g,
 		formatUnderline: /__([\s\S]+?)__(?!_)/g,
 		formatStrike: /~~([\s\S]+?)~~(?!~)/g,
 		formatCodeInline: /(`+)\s*([\s\S]*?[^`])\s*\1(?!`)/g,
@@ -9,7 +9,7 @@ const DISCORD = (function() {
 		formatUrl: /(\b(?:https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig,
 		formatUrlNoEmbed: /<(\b(?:https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])>/ig,
 		specialEscapedBacktick: /\\`/g,
-		specialEscapedSingle: /\\([*\\])/g,
+		specialEscapedSingle: /\\([*_\\])/g,
 		specialEscapedDouble: /\\__|_\\_|\\_\\_|\\~~|~\\~|\\~\\~/g,
 		specialUnescaped: /([*_~\\])/g,
 		mentionRole: /&lt;@&(\d+?)&gt;/g,
@@ -26,6 +26,7 @@ const DISCORD = (function() {
 	let templateUserAvatar;
 	let templateAttachmentDownload;
 	let templateEmbedImage;
+	let templateEmbedImageWithSize;
 	let templateEmbedRich;
 	let templateEmbedRichNoDescription;
 	let templateEmbedUrl;
@@ -46,8 +47,8 @@ const DISCORD = (function() {
 				.replace(regex.specialEscapedSingle, escapeHtmlMatch)
 				.replace(regex.specialEscapedDouble, full => full.replace(/\\/g, "").replace(/(.)/g, escapeHtmlMatch))
 				.replace(regex.formatBold, "<b>$1</b>")
-				.replace(regex.formatItalic, (full, pre, match) => pre === "\\" ? full : (pre || "") + "<i>" + match + "</i>")
 				.replace(regex.formatUnderline, "<u>$1</u>")
+				.replace(regex.formatItalic, (full, pre, char, match) => pre === "\\" ? full : (pre || "") + "<i>" + match + "</i>")
 				.replace(regex.formatStrike, "<s>$1</s>");
 		}
 		
@@ -64,6 +65,25 @@ const DISCORD = (function() {
 		return "<p>" + processed + "</p>";
 	};
 	
+	const getImageEmbed = function(url, image) {
+		if (!SETTINGS.enableImagePreviews) {
+			return "";
+		}
+		
+		if (image.width && image.height) {
+			return templateEmbedImageWithSize.apply({ url, src: image.url, width: image.width, height: image.height });
+		}
+		else {
+			return templateEmbedImage.apply({ url, src: image.url });
+		}
+	};
+	
+	const isImageUrl = function(url) {
+		const dot = url.pathname.lastIndexOf(".");
+		const ext = dot === -1 ? "" : url.pathname.substring(dot).toLowerCase();
+		return ext === ".png" || ext === ".gif" || ext === ".jpg" || ext === ".jpeg";
+	};
+	
 	return {
 		setup() {
 			templateChannelServer = new TEMPLATE([
@@ -109,12 +129,17 @@ const DISCORD = (function() {
 			
 			// noinspection HtmlUnknownTarget
 			templateAttachmentDownload = new TEMPLATE([
-				"<a href='{url}' class='embed download'>Download {filename}</a>"
+				"<a href='{url}' class='embed download'>Download {name}</a>"
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
 			templateEmbedImage = new TEMPLATE([
-				"<a href='{url}' class='embed thumbnail'><img src='{src}' alt='(image attachment not found)'></a><br>"
+				"<a href='{url}' class='embed thumbnail loading'><img src='{src}' alt='' onload='DISCORD.handleImageLoad(this)' onerror='DISCORD.handleImageLoadError(this)'></a><br>"
+			].join(""));
+			
+			// noinspection HtmlUnknownTarget
+			templateEmbedImageWithSize = new TEMPLATE([
+				"<a href='{url}' class='embed thumbnail loading'><img src='{src}' width='{width}' height='{height}' alt='' onload='DISCORD.handleImageLoad(this)' onerror='DISCORD.handleImageLoadError(this)'></a><br>"
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
@@ -145,10 +170,20 @@ const DISCORD = (function() {
 			].join(""));
 		},
 		
+		handleImageLoad(ele) {
+			ele.parentElement.classList.remove("loading");
+		},
+		
+		handleImageLoadError(ele) {
+			// noinspection JSUnusedGlobalSymbols
+			ele.onerror = null;
+			ele.parentElement.classList.remove("loading");
+			ele.setAttribute("alt", "(image attachment not found)");
+		},
+		
 		isImageAttachment(attachment) {
-			const dot = attachment.url.lastIndexOf(".");
+			const url = DOM.tryParseUrl(attachment.url);
-			const ext = dot === -1 ? "" : attachment.url.substring(dot).toLowerCase();
+			return url != null && isImageUrl(url);
-			return ext === ".png" || ext === ".gif" || ext === ".jpg" || ext === ".jpeg";
 		},
 		
 		getChannelHTML(channel) { // noinspection FunctionWithInconsistentReturnsJS
@@ -183,10 +218,10 @@ const DISCORD = (function() {
 							return templateEmbedUnsupported.apply(embed);
 						}
 						else if ("image" in embed && embed.image.url) {
-							return SETTINGS.enableImagePreviews ? templateEmbedImage.apply({ url: embed.url, src: embed.image.url }) : "";
+							return getImageEmbed(embed.url, embed.image);
 						}
 						else if ("thumbnail" in embed && embed.thumbnail.url) {
-							return SETTINGS.enableImagePreviews ? templateEmbedImage.apply({ url: embed.url, src: embed.thumbnail.url }) : "";
+							return getImageEmbed(embed.url, embed.thumbnail);
 						}
 						else if ("title" in embed && "description" in embed) {
 							return templateEmbedRich.apply(embed);
@@ -205,16 +240,14 @@ const DISCORD = (function() {
 					}
 					
 					return value.map(attachment => {
-						if (this.isImageAttachment(attachment) && SETTINGS.enableImagePreviews) {
+						if (!DISCORD.isImageAttachment(attachment) || !SETTINGS.enableImagePreviews) {
-							return templateEmbedImage.apply({ url: attachment.url, src: attachment.url });
+							return templateAttachmentDownload.apply(attachment);
+						}
+						else if ("width" in attachment && "height" in attachment) {
+							return templateEmbedImageWithSize.apply({ url: attachment.url, src: attachment.url, width: attachment.width, height: attachment.height });
 						}
 						else {
-							const sliced = attachment.url.split("/");
+							return templateEmbedImage.apply({ url: attachment.url, src: attachment.url });
-							
-							return templateAttachmentDownload.apply({
-								"url": attachment.url,
-								"filename": sliced[sliced.length - 1]
-							});
 						}
 					}).join("");
 				}

app/Resources/Viewer/scripts/dom.js

@@ -51,4 +51,15 @@ class DOM {
 		const date = new Date(timestamp);
 		return date.toLocaleDateString() + ", " + date.toLocaleTimeString();
 	};
+	
+	/**
+	 * Parses a url string into a URL object and returns it. If the parsing fails, returns null.
+	 */
+	static tryParseUrl(url) {
+		try {
+			return new URL(url);
+		} catch (ignore) {
+			return null;
+		}
+	}
 }

app/Resources/Viewer/styles/messages.css

@@ -107,11 +107,25 @@
 }
 
 .message .thumbnail {
+  position: relative;
   max-width: calc(100% - 20px);
   max-height: 320px;
 }
 
+.message .thumbnail.loading::after {
+  content: "";
+  background: rgba(0, 0, 0, 0.75)
+              url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 300 300' preserveAspectRatio='xMidYMid'%3E %3Ccircle cx='150' cy='150' fill='none' stroke='%237983f5' stroke-width='8' r='42' stroke-dasharray='198 68'%3E %3CanimateTransform attributeName='transform' type='rotate' repeatCount='indefinite' dur='1.25s' values='0 150 150;360 150 150' keyTimes='0;1' /%3E %3C/circle%3E %3C/svg%3E")
+              no-repeat center center;
+  position: absolute;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+}
+
 .message .thumbnail img {
+  width: auto;
   max-width: 100%;
   max-height: 320px;
   border-radius: 3px;

app/Server/Data/Attachment.cs

@@ -5,5 +5,7 @@ namespace DHT.Server.Data {
 		public string? Type { get; internal init; }
 		public string Url { get; internal init; }
 		public ulong Size { get; internal init; }
+		public int? Width { get; internal init; }
+		public int? Height { get; internal init; }
 	}
 }

app/Server/Data/DownloadedAttachment.cs

@@ -0,0 +1,6 @@
+namespace DHT.Server.Data {
+	public readonly struct DownloadedAttachment {
+		public string? Type { get; internal init; }
+		public byte[] Data { get; internal init; }
+	}
+}

app/Server/Data/Filters/AttachmentFilter.cs

@@ -1,6 +1,6 @@
 namespace DHT.Server.Data.Filters {
 	public sealed class AttachmentFilter {
-		public long? MaxBytes { get; set; } = null;
+		public ulong? MaxBytes { get; set; } = null;
 
 		public DownloadItemRules? DownloadItemRule { get; set; } = null;
 

app/Server/Data/ServerType.cs

@@ -24,6 +24,15 @@ namespace DHT.Server.Data {
 			};
 		}
 
+		public static string ToNiceString(ServerType? type) {
+			return type switch {
+				ServerType.Server        => "Server",
+				ServerType.Group         => "Group",
+				ServerType.DirectMessage => "DM",
+				_                        => "Unknown"
+			};
+		}
+
 		internal static string ToJsonViewerString(ServerType? type) {
 			return type switch {
 				ServerType.Server        => "server",

app/Server/Database/DatabaseExtensions.cs

@@ -1,16 +1,11 @@
+using System.Collections.Generic;
 using DHT.Server.Data;
 
 namespace DHT.Server.Database {
 	public static class DatabaseExtensions {
 		public static void AddFrom(this IDatabaseFile target, IDatabaseFile source) {
-			foreach (var server in source.GetAllServers()) {
+			target.AddServers(source.GetAllServers());
-				target.AddServer(server);
+			target.AddChannels(source.GetAllChannels());
-			}
-
-			foreach (var channel in source.GetAllChannels()) {
-				target.AddChannel(channel);
-			}
-
 			target.AddUsers(source.GetAllUsers().ToArray());
 			target.AddMessages(source.GetMessages().ToArray());
 			
@@ -18,5 +13,17 @@ namespace DHT.Server.Database {
 				target.AddDownload(download.Status == DownloadStatus.Success ? source.GetDownloadWithData(download) : download);
 			}
 		}
+
+		internal static void AddServers(this IDatabaseFile target, IEnumerable<Data.Server> servers) {
+			foreach (var server in servers) {
+				target.AddServer(server);
+			}
+		}
+
+		internal static void AddChannels(this IDatabaseFile target, IEnumerable<Channel> channels) {
+			foreach (var channel in channels) {
+				target.AddChannel(channel);
+			}
+		}
 	}
 }

app/Server/Database/DummyDatabaseFile.cs

@@ -45,6 +45,10 @@ namespace DHT.Server.Database {
 			return new();
 		}
 
+		public HashSet<ulong> GetMessageIds(MessageFilter? filter = null) {
+			return new();
+		}
+
 		public void RemoveMessages(MessageFilter filter, FilterRemovalMode mode) {}
 
 		public int CountAttachments(AttachmentFilter? filter = null) {
@@ -59,6 +63,10 @@ namespace DHT.Server.Database {
 			return download;
 		}
 
+		public DownloadedAttachment? GetDownloadedAttachment(string url) {
+			return null;
+		}
+
 		public void AddDownload(Data.Download download) {}
 
 		public void EnqueueDownloadItems(AttachmentFilter? filter = null) {}

app/Server/Database/Export/Strategy/IViewerExportStrategy.cs

@@ -0,0 +1,7 @@
+using DHT.Server.Data;
+
+namespace DHT.Server.Database.Export.Strategy {
+	public interface IViewerExportStrategy {
+		string GetAttachmentUrl(Attachment attachment);
+	}
+}

app/Server/Database/Export/Strategy/LiveViewerExportStrategy.cs

@@ -0,0 +1,18 @@
+using System.Net;
+using DHT.Server.Data;
+
+namespace DHT.Server.Database.Export.Strategy {
+	public sealed class LiveViewerExportStrategy : IViewerExportStrategy {
+		private readonly string safePort;
+		private readonly string safeToken;
+		
+		public LiveViewerExportStrategy(ushort port, string token) {
+			this.safePort = port.ToString();
+			this.safeToken = WebUtility.UrlEncode(token);
+		}
+
+		public string GetAttachmentUrl(Attachment attachment) {
+			return "http://127.0.0.1:" + safePort + "/get-attachment/" + WebUtility.UrlEncode(attachment.Url) + "?token=" + safeToken;
+		}
+	}
+}

app/Server/Database/Export/Strategy/StandaloneViewerExportStrategy.cs

@@ -0,0 +1,13 @@
+using DHT.Server.Data;
+
+namespace DHT.Server.Database.Export.Strategy {
+	public sealed class StandaloneViewerExportStrategy : IViewerExportStrategy {
+		public static StandaloneViewerExportStrategy Instance { get; } = new ();
+
+		private StandaloneViewerExportStrategy() {}
+
+		public string GetAttachmentUrl(Attachment attachment) {
+			return attachment.Url;
+		}
+	}
+}

app/Server/Database/Export/ViewerJsonExport.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -5,13 +6,14 @@ using System.Text.Json;
 using System.Threading.Tasks;
 using DHT.Server.Data;
 using DHT.Server.Data.Filters;
+using DHT.Server.Database.Export.Strategy;
 using DHT.Utils.Logging;
 
 namespace DHT.Server.Database.Export {
 	public static class ViewerJsonExport {
 		private static readonly Log Log = Log.ForType(typeof(ViewerJsonExport));
 
-		public static async Task Generate(Stream stream, IDatabaseFile db, MessageFilter? filter = null) {
+		public static async Task Generate(Stream stream, IViewerExportStrategy strategy, IDatabaseFile db, MessageFilter? filter = null) {
 			var perf = Log.Start();
 
 			var includedUserIds = new HashSet<ulong>();
@@ -41,7 +43,7 @@ namespace DHT.Server.Database.Export {
 
 			var value = new {
 				meta = new { users, userindex, servers, channels },
-				data = GenerateMessageList(includedMessages, userIndices)
+				data = GenerateMessageList(includedMessages, userIndices, strategy)
 			};
 			
 			perf.Step("Generate value object");
@@ -138,7 +140,7 @@ namespace DHT.Server.Database.Export {
 			return channels;
 		}
 
-		private static object GenerateMessageList(List<Message> includedMessages, Dictionary<ulong, object> userIndices) {
+		private static object GenerateMessageList( List<Message> includedMessages, Dictionary<ulong, object> userIndices, IViewerExportStrategy strategy) {
 			var data = new Dictionary<string, Dictionary<string, object>>();
 
 			foreach (var grouping in includedMessages.GroupBy(static message => message.Channel)) {
@@ -164,8 +166,18 @@ namespace DHT.Server.Database.Export {
 					}
 
 					if (!message.Attachments.IsEmpty) {
-						obj["a"] = message.Attachments.Select(static attachment => new Dictionary<string, object> {
+						obj["a"] = message.Attachments.Select(attachment => {
-							{ "url", attachment.Url }
+							var a = new Dictionary<string, object> {
+								{ "url", strategy.GetAttachmentUrl(attachment) },
+								{ "name", Uri.TryCreate(attachment.Url, UriKind.Absolute, out var uri) ? Path.GetFileName(uri.LocalPath) : attachment.Url }
+							};
+
+							if (attachment.Width != null && attachment.Height != null) {
+								a["width"] = attachment.Width;
+								a["height"] = attachment.Height;
+							}
+							
+							return a;
 						}).ToArray();
 					}
 
@@ -188,7 +200,7 @@ namespace DHT.Server.Database.Export {
 							r["a"] = reaction.EmojiFlags.HasFlag(EmojiFlags.Animated);
 							r["c"] = reaction.Count;
 							return r;
-						});
+						}).ToArray();
 					}
 
 					channelData[message.Id.ToString()] = obj;

app/Server/Database/IDatabaseFile.cs

@@ -23,6 +23,7 @@ namespace DHT.Server.Database {
 		void AddMessages(Message[] messages);
 		int CountMessages(MessageFilter? filter = null);
 		List<Message> GetMessages(MessageFilter? filter = null);
+		HashSet<ulong> GetMessageIds(MessageFilter? filter = null);
 		void RemoveMessages(MessageFilter filter, FilterRemovalMode mode);
 
 		int CountAttachments(AttachmentFilter? filter = null);
@@ -30,6 +31,7 @@ namespace DHT.Server.Database {
 		void AddDownload(Data.Download download);
 		List<Data.Download> GetDownloadsWithoutData();
 		Data.Download GetDownloadWithData(Data.Download download);
+		DownloadedAttachment? GetDownloadedAttachment(string url);
 
 		void EnqueueDownloadItems(AttachmentFilter? filter = null);
 		List<DownloadItem> GetEnqueuedDownloadItems(int count);

app/Server/Database/Import/FakeSnowflake.cs

@@ -0,0 +1,21 @@
+using System;
+
+namespace DHT.Server.Database.Import {
+	/// <summary>
+	/// https://discord.com/developers/docs/reference#snowflakes
+	/// </summary>
+	public sealed class FakeSnowflake {
+		private const ulong DiscordEpoch = 1420070400000UL;
+			
+		private ulong id;
+
+		public FakeSnowflake() {
+			var unixMillis = (ulong) (DateTime.UtcNow.Subtract(DateTime.UnixEpoch).Ticks / TimeSpan.TicksPerMillisecond);
+			this.id = (unixMillis - DiscordEpoch) << 22;
+		}
+
+		internal ulong Next() {
+			return id++;
+		}
+	}
+}

app/Server/Database/Import/LegacyArchiveImport.cs

@@ -0,0 +1,263 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Linq;
+using System.Text.Json;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+using DHT.Utils.Collections;
+using DHT.Utils.Http;
+using DHT.Utils.Logging;
+using Microsoft.AspNetCore.StaticFiles;
+
+namespace DHT.Server.Database.Import {
+	public static class LegacyArchiveImport {
+		private static readonly Log Log = Log.ForType(typeof(LegacyArchiveImport));
+
+		private static readonly FileExtensionContentTypeProvider ContentTypeProvider = new ();
+
+		public static async Task<bool> Read(Stream stream, IDatabaseFile db, FakeSnowflake fakeSnowflake, Func<Data.Server[], Task<Dictionary<Data.Server, ulong>?>> askForServerIds) {
+			var perf = Log.Start();
+			var root = await JsonSerializer.DeserializeAsync<JsonElement>(stream);
+
+			try {
+				var meta = root.RequireObject("meta");
+				var data = root.RequireObject("data");
+
+				perf.Step("Deserialize JSON");
+
+				var users = ReadUserList(meta);
+				var servers = ReadServerList(meta, fakeSnowflake);
+
+				var newServersOnly = new HashSet<Data.Server>(servers);
+				var oldServersById = db.GetAllServers().ToDictionary(static server => server.Id, static server => server);
+
+				var oldChannels = db.GetAllChannels();
+				var oldChannelsById = oldChannels.ToDictionary(static channel => channel.Id, static channel => channel);
+
+				foreach (var (channelId, serverIndex) in ReadChannelToServerIndexMapping(meta, servers)) {
+					if (oldChannelsById.TryGetValue(channelId, out var oldChannel) && oldServersById.TryGetValue(oldChannel.Server, out var oldServer) && newServersOnly.Remove(servers[serverIndex])) {
+						servers[serverIndex] = oldServer;
+					}
+				}
+
+				perf.Step("Read server and user list");
+
+				if (newServersOnly.Count > 0) {
+					var askedServerIds = await askForServerIds(newServersOnly.ToArray());
+					if (askedServerIds == null) {
+						return false;
+					}
+
+					perf.Step("Ask for server IDs");
+
+					for (var i = 0; i < servers.Length; i++) {
+						var server = servers[i];
+						if (askedServerIds.TryGetValue(server, out var serverId)) {
+							servers[i] = new Data.Server {
+								Id = serverId,
+								Name = server.Name,
+								Type = server.Type
+							};
+						}
+					}
+				}
+
+				var channels = ReadChannelList(meta, servers);
+
+				perf.Step("Read channel list");
+
+				var oldMessageIds = db.GetMessageIds();
+				var newMessages = channels.SelectMany(channel => ReadMessages(data, channel, users, fakeSnowflake))
+				                          .Where(message => !oldMessageIds.Contains(message.Id))
+				                          .ToArray();
+
+				perf.Step("Read messages");
+
+				db.AddUsers(users);
+				db.AddServers(servers);
+				db.AddChannels(channels);
+				db.AddMessages(newMessages);
+
+				perf.Step("Import into database");
+			} catch (HttpException e) {
+				throw new JsonException(e.Message);
+			}
+
+			perf.End();
+			return true;
+		}
+
+		private static User[] ReadUserList(JsonElement meta) {
+			const string UsersPath = "meta.users[]";
+
+			static ulong ParseUserIndex(JsonElement element, int index) {
+				return ulong.Parse(element.GetString() ?? throw new JsonException("Expected key 'meta.userindex[" + index + "]' to be a string."));
+			}
+
+			var userindex = meta.RequireArray("userindex", "meta")
+			                    .Select(static (item, index) => (ParseUserIndex(item, index), index))
+			                    .ToDictionary();
+
+			var users = new User[userindex.Count];
+
+			foreach (var item in meta.RequireObject("users", "meta").EnumerateObject()) {
+				var path = UsersPath + "." + item.Name;
+				var userId = ulong.Parse(item.Name);
+				var userObj = item.Value;
+
+				users[userindex[userId]] = new User {
+					Id = userId,
+					Name = userObj.RequireString("name", path),
+					AvatarUrl = userObj.HasKey("avatar") ? userObj.RequireString("avatar", path) : null,
+					Discriminator = userObj.HasKey("tag") ? userObj.RequireString("tag", path) : null
+				};
+			}
+
+			return users;
+		}
+
+		private static Data.Server[] ReadServerList(JsonElement meta, FakeSnowflake fakeSnowflake) {
+			const string ServersPath = "meta.servers[]";
+
+			return meta.RequireArray("servers", "meta").Select(serverObj => new Data.Server {
+				Id = fakeSnowflake.Next(),
+				Name = serverObj.RequireString("name", ServersPath),
+				Type = ServerTypes.FromString(serverObj.RequireString("type", ServersPath))
+			}).ToArray();
+		}
+
+		private const string ChannelsPath = "meta.channels";
+
+		private static Dictionary<ulong, int> ReadChannelToServerIndexMapping(JsonElement meta, Data.Server[] servers) {
+			return meta.RequireObject("channels", "meta").EnumerateObject().Select(item => {
+				var path = ChannelsPath + "." + item.Name;
+				var channelId = ulong.Parse(item.Name);
+				var channelObj = item.Value;
+
+				return (channelId, channelObj.RequireInt("server", path, min: 0, max: servers.Length - 1));
+			}).ToDictionary();
+		}
+
+		private static Channel[] ReadChannelList(JsonElement meta, Data.Server[] servers) {
+			return meta.RequireObject("channels", "meta").EnumerateObject().Select(item => {
+				var path = ChannelsPath + "." + item.Name;
+				var channelId = ulong.Parse(item.Name);
+				var channelObj = item.Value;
+
+				return new Channel {
+					Id = channelId,
+					Server = servers[channelObj.RequireInt("server", path, min: 0, max: servers.Length - 1)].Id,
+					Name = channelObj.RequireString("name", path),
+					Position = channelObj.HasKey("position") ? channelObj.RequireInt("position", path, min: 0) : null,
+					Topic = channelObj.HasKey("topic") ? channelObj.RequireString("topic", path) : null,
+					Nsfw = channelObj.HasKey("nsfw") ? channelObj.RequireBool("nsfw", path) : null
+				};
+			}).ToArray();
+		}
+
+		private static Message[] ReadMessages(JsonElement data, Channel channel, User[] users, FakeSnowflake fakeSnowflake) {
+			const string DataPath = "data";
+
+			var channelId = channel.Id;
+			var channelIdStr = channelId.ToString();
+
+			var messagesObj = data.HasKey(channelIdStr) ? data.RequireObject(channelIdStr, DataPath) : (JsonElement?) null;
+			if (messagesObj == null) {
+				return Array.Empty<Message>();
+			}
+
+			return messagesObj.Value.EnumerateObject().Select(item => {
+				var path = DataPath + "." + item.Name;
+				var messageId = ulong.Parse(item.Name);
+				var messageObj = item.Value;
+
+				return new Message {
+					Id = messageId,
+					Sender = users[messageObj.RequireInt("u", path, min: 0, max: users.Length - 1)].Id,
+					Channel = channelId,
+					Text = messageObj.HasKey("m") ? messageObj.RequireString("m", path) : string.Empty,
+					Timestamp = messageObj.RequireLong("t", path),
+					EditTimestamp = messageObj.HasKey("te") ? messageObj.RequireLong("te", path) : null,
+					RepliedToId = messageObj.HasKey("r") ? messageObj.RequireSnowflake("r", path) : null,
+					Attachments = messageObj.HasKey("a") ? ReadMessageAttachments(messageObj.RequireArray("a", path), fakeSnowflake, path + ".a[]").ToImmutableArray() : ImmutableArray<Attachment>.Empty,
+					Embeds = messageObj.HasKey("e") ? ReadMessageEmbeds(messageObj.RequireArray("e", path), path + ".e[]").ToImmutableArray() : ImmutableArray<Embed>.Empty,
+					Reactions = messageObj.HasKey("re") ? ReadMessageReactions(messageObj.RequireArray("re", path), path + ".re[]").ToImmutableArray() : ImmutableArray<Reaction>.Empty
+				};
+			}).ToArray();
+		}
+
+		[SuppressMessage("ReSharper", "ConvertToLambdaExpression")]
+		private static IEnumerable<Attachment> ReadMessageAttachments(JsonElement.ArrayEnumerator attachmentsArray, FakeSnowflake fakeSnowflake, string path) {
+			return attachmentsArray.Select(attachmentObj => {
+				string url = attachmentObj.RequireString("url", path);
+				string name = url[(url.LastIndexOf('/') + 1)..];
+				string? type = ContentTypeProvider.TryGetContentType(name, out var contentType) ? contentType : null;
+
+				return new Attachment {
+					Id = fakeSnowflake.Next(),
+					Name = name,
+					Type = type,
+					Url = url,
+					Size = 0 // unknown size
+				};
+			}).DistinctByKeyStable(static attachment => {
+				// Some Discord messages have duplicate attachments with the same id for unknown reasons.
+				return attachment.Id;
+			});
+		}
+
+		private static IEnumerable<Embed> ReadMessageEmbeds(JsonElement.ArrayEnumerator embedsArray, string path) {
+			// Some rich embeds are missing URLs which causes a missing 'url' key.
+			return embedsArray.Where(static embedObj => embedObj.HasKey("url")).Select(embedObj => {
+				string url = embedObj.RequireString("url", path);
+				string type = embedObj.RequireString("type", path);
+
+				var embedJson = new Dictionary<string, object> {
+					{ "url", url },
+					{ "type", type },
+					{ "dht_legacy", true }
+				};
+
+				if (type == "image") {
+					embedJson["image"] = new Dictionary<string, string> {
+						{ "url", url }
+					};
+				}
+				else if (type == "rich") {
+					if (embedObj.HasKey("t")) {
+						embedJson["title"] = embedObj.RequireString("t", path);
+					}
+
+					if (embedObj.HasKey("d")) {
+						embedJson["description"] = embedObj.RequireString("d", path);
+					}
+				}
+
+				return new Embed {
+					Json = JsonSerializer.Serialize(embedJson)
+				};
+			});
+		}
+
+		private static IEnumerable<Reaction> ReadMessageReactions(JsonElement.ArrayEnumerator reactionsArray, string path) {
+			return reactionsArray.Select(reactionObj => {
+				var id = reactionObj.HasKey("id") ? reactionObj.RequireSnowflake("id", path) : (ulong?) null;
+				var name = reactionObj.HasKey("n") ? reactionObj.RequireString("n", path) : null;
+
+				if (id == null && name == null) {
+					throw new JsonException("Expected key '" + path + ".id' and/or '" + path + ".n' to be present.");
+				}
+
+				return new Reaction {
+					EmojiId = id,
+					EmojiName = name,
+					EmojiFlags = reactionObj.HasKey("an") && reactionObj.RequireBool("an", path) ? EmojiFlags.Animated : EmojiFlags.None,
+					Count = reactionObj.RequireInt("c", path, min: 0)
+				};
+			});
+		}
+	}
+}

app/Server/Database/Sqlite/Schema.cs

@@ -6,7 +6,7 @@ using DHT.Utils.Logging;
 
 namespace DHT.Server.Database.Sqlite {
 	sealed class Schema {
-		internal const int Version = 4;
+		internal const int Version = 5;
 
 		private static readonly Log Log = Log.ForType<Schema>();
 
@@ -79,7 +79,9 @@ namespace DHT.Server.Database.Sqlite {
 			        name TEXT NOT NULL,
 			        type TEXT,
 			        url TEXT NOT NULL,
-			        size INTEGER NOT NULL)");
+			        size INTEGER NOT NULL,
+			        width INTEGER,
+			        height INTEGER)");
 
 			Execute(@"CREATE TABLE embeds (
 			        message_id INTEGER NOT NULL,
@@ -159,6 +161,12 @@ namespace DHT.Server.Database.Sqlite {
 				perf.Step("Upgrade to version 4");
 			}
 
+			if (dbVersion <= 4) {
+				Execute("ALTER TABLE attachments ADD width INTEGER");
+				Execute("ALTER TABLE attachments ADD height INTEGER");
+				perf.Step("Upgrade to version 5");
+			}
+
 			perf.End();
 		}
 	}

app/Server/Database/Sqlite/SqliteDatabaseFile.cs

@@ -252,7 +252,9 @@ namespace DHT.Server.Database.Sqlite {
 					("name", SqliteType.Text),
 					("type", SqliteType.Text),
 					("url", SqliteType.Text),
-					("size", SqliteType.Integer)
+					("size", SqliteType.Integer),
+					("width", SqliteType.Integer),
+					("height", SqliteType.Integer)
 				});
 
 				using var embedCmd = conn.Insert("embeds", new[] {
@@ -307,6 +309,8 @@ namespace DHT.Server.Database.Sqlite {
 							attachmentCmd.Set(":type", attachment.Type);
 							attachmentCmd.Set(":url", attachment.Url);
 							attachmentCmd.Set(":size", attachment.Size);
+							attachmentCmd.Set(":width", attachment.Width);
+							attachmentCmd.Set(":height", attachment.Height);
 							attachmentCmd.ExecuteNonQuery();
 						}
 					}
@@ -386,22 +390,34 @@ LEFT JOIN replied_to rt ON m.message_id = rt.message_id" + filter.GenerateWhereC
 			return list;
 		}
 
-		public void RemoveMessages(MessageFilter filter, FilterRemovalMode mode) {
+		public HashSet<ulong> GetMessageIds(MessageFilter? filter = null) {
-			var whereClause = filter.GenerateWhereClause(invert: mode == FilterRemovalMode.KeepMatching);
+			var perf = log.Start();
+			var ids = new HashSet<ulong>();
 
-			if (!string.IsNullOrEmpty(whereClause)) {
+			using var conn = pool.Take();
+			using var cmd = conn.Command("SELECT message_id FROM messages" + filter.GenerateWhereClause());
+			using var reader = cmd.ExecuteReader();
+
+			while (reader.Read()) {
+				ids.Add(reader.GetUint64(0));
+			}
+
+			perf.End();
+			return ids;
+		}
+
+		public void RemoveMessages(MessageFilter filter, FilterRemovalMode mode) {
 			var perf = log.Start();
 
-				DeleteFromTable("messages", whereClause);
+			DeleteFromTable("messages", filter.GenerateWhereClause(invert: mode == FilterRemovalMode.KeepMatching));
 			totalMessagesComputer.Recompute();
 
 			perf.End();
 		}
-		}
 
 		public int CountAttachments(AttachmentFilter? filter = null) {
 			using var conn = pool.Take();
-			using var cmd = conn.Command("SELECT COUNT(*) FROM attachments a" + filter.GenerateWhereClause("a"));
+			using var cmd = conn.Command("SELECT COUNT(DISTINCT url) FROM attachments a" + filter.GenerateWhereClause("a"));
 			using var reader = cmd.ExecuteReader();
 
 			return reader.Read() ? reader.GetInt32(0) : 0;
@@ -458,9 +474,31 @@ LEFT JOIN replied_to rt ON m.message_id = rt.message_id" + filter.GenerateWhereC
 			}
 		}
 
+		public DownloadedAttachment? GetDownloadedAttachment(string url) {
+			using var conn = pool.Take();
+			using var cmd = conn.Command(@"
+SELECT a.type, d.blob FROM downloads d
+LEFT JOIN attachments a ON d.url = a.url
+WHERE d.url = :url AND d.status = :success AND d.blob IS NOT NULL");
+			
+			cmd.AddAndSet(":url", SqliteType.Text, url);
+			cmd.AddAndSet(":success", SqliteType.Integer, (int) DownloadStatus.Success);
+			
+			using var reader = cmd.ExecuteReader();
+
+			if (!reader.Read()) {
+				return null;
+			}
+			
+			return new DownloadedAttachment {
+				Type = reader.IsDBNull(0) ? null : reader.GetString(0),
+				Data = (byte[]) reader["blob"]
+			};
+		}
+
 		public void EnqueueDownloadItems(AttachmentFilter? filter = null) {
 			using var conn = pool.Take();
-			using var cmd = conn.Command("INSERT INTO downloads (url, status, size) SELECT a.url, :enqueued, a.size FROM attachments a" + filter.GenerateWhereClause("a"));
+			using var cmd = conn.Command("INSERT INTO downloads (url, status, size) SELECT a.url, :enqueued, MAX(a.size) FROM attachments a" + filter.GenerateWhereClause("a") + " GROUP BY a.url");
 			cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
 			cmd.ExecuteNonQuery();
 		}
@@ -486,16 +524,13 @@ LEFT JOIN replied_to rt ON m.message_id = rt.message_id" + filter.GenerateWhereC
 		}
 
 		public void RemoveDownloadItems(DownloadItemFilter? filter, FilterRemovalMode mode) {
-			var whereClause = filter.GenerateWhereClause(invert: mode == FilterRemovalMode.KeepMatching);
+			DeleteFromTable("downloads", filter.GenerateWhereClause(invert: mode == FilterRemovalMode.KeepMatching));
-			
+			totalDownloadsComputer.Recompute();
-			if (!string.IsNullOrEmpty(whereClause)) {
-				DeleteFromTable("downloads", whereClause);
-			}
 		}
 
 		public DownloadStatusStatistics GetDownloadStatusStatistics() {
 			static void LoadUndownloadedStatistics(ISqliteConnection conn, DownloadStatusStatistics result) {
-				using var cmd = conn.Command("SELECT IFNULL(COUNT(filtered.size), 0), IFNULL(SUM(filtered.size), 0) FROM (SELECT DISTINCT a.url, a.size FROM attachments a  WHERE a.url NOT IN (SELECT d.url FROM downloads d)) filtered");
+				using var cmd = conn.Command("SELECT IFNULL(COUNT(size), 0), IFNULL(SUM(size), 0) FROM (SELECT MAX(a.size) size FROM attachments a WHERE a.url NOT IN (SELECT d.url FROM downloads d) GROUP BY a.url)");
 				using var reader = cmd.ExecuteReader();
 
 				if (reader.Read()) {
@@ -540,7 +575,7 @@ FROM downloads");
 			var dict = new MultiDictionary<ulong, Attachment>();
 
 			using var conn = pool.Take();
-			using var cmd = conn.Command("SELECT message_id, attachment_id, name, type, url, size FROM attachments");
+			using var cmd = conn.Command("SELECT message_id, attachment_id, name, type, url, size, width, height FROM attachments");
 			using var reader = cmd.ExecuteReader();
 
 			while (reader.Read()) {
@@ -551,7 +586,9 @@ FROM downloads");
 					Name = reader.GetString(2),
 					Type = reader.IsDBNull(3) ? null : reader.GetString(3),
 					Url = reader.GetString(4),
-					Size = reader.GetUint64(5)
+					Size = reader.GetUint64(5),
+					Width = reader.IsDBNull(6) ? null : reader.GetInt32(6),
+					Height = reader.IsDBNull(7) ? null : reader.GetInt32(7)
 				});
 			}
 
@@ -639,7 +676,7 @@ FROM downloads");
 
 		private long ComputeAttachmentStatistics() {
 			using var conn = pool.Take();
-			return conn.SelectScalar("SELECT COUNT(*) FROM attachments") as long? ?? 0L;
+			return conn.SelectScalar("SELECT COUNT(DISTINCT url) FROM attachments") as long? ?? 0L;
 		}
 
 		private void UpdateAttachmentStatistics(long totalAttachments) {

app/Server/Database/Sqlite/Utils/SqliteConnectionPool.cs

@@ -45,22 +45,21 @@ namespace DHT.Server.Database.Sqlite.Utils {
 		}
 
 		public ISqliteConnection Take() {
-			PooledConnection? conn = null;
+			while (true) {
-			
-			while (conn == null) {
 				ThrowIfDisposed();
+				
 				lock (monitor) {
-					if (free.TryTake(out conn, TimeSpan.FromMilliseconds(rand.Next(100, 200)))) {
+					if (free.TryTake(out var conn)) {
 						used.Add(conn);
-						break;
+						return conn;
 					}
 					else {
 						Log.ForType<SqliteConnectionPool>().Warn("Thread " + Thread.CurrentThread.ManagedThreadId + " is starving for connections.");
 					}
 				}
-			}
 				
-			return conn;
+				Thread.Sleep(TimeSpan.FromMilliseconds(rand.Next(100, 200)));
+			}
 		}
 
 		private void Return(PooledConnection conn) {

app/Server/Endpoints/BaseEndpoint.cs

@@ -8,6 +8,7 @@ using DHT.Utils.Http;
 using DHT.Utils.Logging;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Extensions;
+using Microsoft.Extensions.Primitives;
 
 namespace DHT.Server.Endpoints {
 	abstract class BaseEndpoint {
@@ -21,26 +22,22 @@ namespace DHT.Server.Endpoints {
 			this.parameters = parameters;
 		}
 
-		public async Task Handle(HttpContext ctx) {
+		private async Task Handle(HttpContext ctx, StringValues token) {
 			var request = ctx.Request;
 			var response = ctx.Response;
 
 			Log.Info("Request: " + request.GetDisplayUrl() + " (" + request.ContentLength + " B)");
 			
-			var requestToken = request.Headers["X-DHT-Token"];
+			if (token.Count != 1 || token[0] != parameters.Token) {
-			if (requestToken.Count != 1 || requestToken[0] != parameters.Token) {
+				Log.Error("Token: " + (token.Count == 1 ? token[0] : "<missing>"));
-				Log.Error("Token: " + (requestToken.Count == 1 ? requestToken[0] : "<missing>"));
 				response.StatusCode = (int) HttpStatusCode.Forbidden;
 				return;
 			}
 
 			try {
-				var (statusCode, output) = await Respond(ctx);
+				response.StatusCode = (int) HttpStatusCode.OK;
-				response.StatusCode = (int) statusCode;
+				var output = await Respond(ctx);
-
+				await output.WriteTo(response);
-				if (output != null) {
-					await response.WriteAsJsonAsync(output);
-				}
 			} catch (HttpException e) {
 				Log.Error(e);
 				response.StatusCode = (int) e.StatusCode;
@@ -51,7 +48,15 @@ namespace DHT.Server.Endpoints {
 			}
 		}
 
-		protected abstract Task<(HttpStatusCode, object?)> Respond(HttpContext ctx);
+		public async Task HandleGet(HttpContext ctx) {
+			await Handle(ctx, ctx.Request.Query["token"]);
+		}
+
+		public async Task HandlePost(HttpContext ctx) {
+			await Handle(ctx, ctx.Request.Headers["X-DHT-Token"]);
+		}
+
+		protected abstract Task<IHttpOutput> Respond(HttpContext ctx);
 
 		protected static async Task<JsonElement> ReadJson(HttpContext ctx) {
 			return await ctx.Request.ReadFromJsonAsync<JsonElement?>() ?? throw new HttpException(HttpStatusCode.UnsupportedMediaType, "This endpoint only accepts JSON.");

app/Server/Endpoints/GetAttachmentEndpoint.cs

@@ -0,0 +1,25 @@
+using System.Net;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+using DHT.Server.Database;
+using DHT.Server.Service;
+using DHT.Utils.Http;
+using Microsoft.AspNetCore.Http;
+
+namespace DHT.Server.Endpoints {
+	sealed class GetAttachmentEndpoint : BaseEndpoint {
+		public GetAttachmentEndpoint(IDatabaseFile db, ServerParameters parameters) : base(db, parameters) {}
+		
+		protected override Task<IHttpOutput> Respond(HttpContext ctx) {
+			string attachmentUrl = WebUtility.UrlDecode((string) ctx.Request.RouteValues["url"]!);
+			DownloadedAttachment? maybeDownloadedAttachment = Db.GetDownloadedAttachment(attachmentUrl);
+
+			if (maybeDownloadedAttachment is {} downloadedAttachment) {
+				return Task.FromResult<IHttpOutput>(new HttpOutput.File(downloadedAttachment.Type, downloadedAttachment.Data));
+			}
+			else {
+				return Task.FromResult<IHttpOutput>(new HttpOutput.Redirect(attachmentUrl, permanent: false));
+			}
+		}
+	}
+}

app/Server/Endpoints/TrackChannelEndpoint.cs

@@ -11,7 +11,7 @@ namespace DHT.Server.Endpoints {
 	sealed class TrackChannelEndpoint : BaseEndpoint {
 		public TrackChannelEndpoint(IDatabaseFile db, ServerParameters parameters) : base(db, parameters) {}
 
-		protected override async Task<(HttpStatusCode, object?)> Respond(HttpContext ctx) {
+		protected override async Task<IHttpOutput> Respond(HttpContext ctx) {
 			var root = await ReadJson(ctx);
 			var server = ReadServer(root.RequireObject("server"), "server");
 			var channel = ReadChannel(root.RequireObject("channel"), "channel", server.Id);
@@ -19,7 +19,7 @@ namespace DHT.Server.Endpoints {
 			Db.AddServer(server);
 			Db.AddChannel(channel);
 
-			return (HttpStatusCode.OK, null);
+			return HttpOutput.None;
 		}
 
 		private static Data.Server ReadServer(JsonElement json, string path) => new() {

app/Server/Endpoints/TrackMessagesEndpoint.cs

@@ -17,7 +17,7 @@ namespace DHT.Server.Endpoints {
 	sealed class TrackMessagesEndpoint : BaseEndpoint {
 		public TrackMessagesEndpoint(IDatabaseFile db, ServerParameters parameters) : base(db, parameters) {}
 
-		protected override async Task<(HttpStatusCode, object?)> Respond(HttpContext ctx) {
+		protected override async Task<IHttpOutput> Respond(HttpContext ctx) {
 			var root = await ReadJson(ctx);
 
 			if (root.ValueKind != JsonValueKind.Array) {
@@ -39,7 +39,7 @@ namespace DHT.Server.Endpoints {
 
 			Db.AddMessages(messages);
 
-			return (HttpStatusCode.OK, anyNewMessages ? 1 : 0);
+			return new HttpOutput.Json(anyNewMessages ? 1 : 0);
 		}
 
 		private static Message ReadMessage(JsonElement json, string path) => new() {
@@ -61,7 +61,9 @@ namespace DHT.Server.Endpoints {
 			Name = ele.RequireString("name", path),
 			Type = ele.HasKey("type") ? ele.RequireString("type", path) : null,
 			Url = ele.RequireString("url", path),
-			Size = (ulong) ele.RequireLong("size", path)
+			Size = (ulong) ele.RequireLong("size", path),
+			Width = ele.HasKey("width") ? ele.RequireInt("width", path) : null,
+			Height = ele.HasKey("height") ? ele.RequireInt("height", path) : null
 		}).DistinctByKeyStable(static attachment => {
 			// Some Discord messages have duplicate attachments with the same id for unknown reasons.
 			return attachment.Id;

app/Server/Endpoints/TrackUsersEndpoint.cs

@@ -11,7 +11,7 @@ namespace DHT.Server.Endpoints {
 	sealed class TrackUsersEndpoint : BaseEndpoint {
 		public TrackUsersEndpoint(IDatabaseFile db, ServerParameters parameters) : base(db, parameters) {}
 
-		protected override async Task<(HttpStatusCode, object?)> Respond(HttpContext ctx) {
+		protected override async Task<IHttpOutput> Respond(HttpContext ctx) {
 			var root = await ReadJson(ctx);
 
 			if (root.ValueKind != JsonValueKind.Array) {
@@ -27,7 +27,7 @@ namespace DHT.Server.Endpoints {
 
 			Db.AddUsers(users);
 
-			return (HttpStatusCode.OK, null);
+			return HttpOutput.None;
 		}
 
 		private static User ReadUser(JsonElement json, string path) => new() {

app/Server/Server.csproj

@@ -20,7 +20,7 @@
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.Data.Sqlite" Version="6.0.5" />
+    <PackageReference Include="Microsoft.Data.Sqlite" Version="6.0.7" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Utils\Utils.csproj" />

app/Server/Service/ServerStartup.cs

@@ -9,6 +9,13 @@ using Microsoft.Extensions.Hosting;
 
 namespace DHT.Server.Service {
 	sealed class Startup {
+		private static readonly string[] AllowedOrigins = {
+			"https://discord.com",
+			"https://ptb.discord.com",
+			"https://canary.discord.com",
+			"https://discordapp.com"
+		};
+
 		public void ConfigureServices(IServiceCollection services) {
 			services.Configure<JsonOptions>(static options => {
 				options.SerializerOptions.NumberHandling = JsonNumberHandling.Strict;
@@ -16,7 +23,7 @@ namespace DHT.Server.Service {
 
 			services.AddCors(static cors => {
 				cors.AddDefaultPolicy(static builder => {
-					builder.WithOrigins("https://discord.com", "https://discordapp.com").AllowCredentials().AllowAnyMethod().AllowAnyHeader();
+					builder.WithOrigins(AllowedOrigins).AllowCredentials().AllowAnyMethod().AllowAnyHeader();
 				});
 			});
 		}
@@ -27,13 +34,16 @@ namespace DHT.Server.Service {
 			app.UseCors();
 			app.UseEndpoints(endpoints => {
 				TrackChannelEndpoint trackChannel = new(db, parameters);
-				endpoints.MapPost("/track-channel", async context => await trackChannel.Handle(context));
+				endpoints.MapPost("/track-channel", async context => await trackChannel.HandlePost(context));
 
 				TrackUsersEndpoint trackUsers = new(db, parameters);
-				endpoints.MapPost("/track-users", async context => await trackUsers.Handle(context));
+				endpoints.MapPost("/track-users", async context => await trackUsers.HandlePost(context));
 
 				TrackMessagesEndpoint trackMessages = new(db, parameters);
-				endpoints.MapPost("/track-messages", async context => await trackMessages.Handle(context));
+				endpoints.MapPost("/track-messages", async context => await trackMessages.HandlePost(context));
+
+				GetAttachmentEndpoint getAttachment = new(db, parameters);
+				endpoints.MapGet("/get-attachment/{url}", async context => await getAttachment.HandleGet(context));
 			});
 		}
 	}

app/Utils/Collections/LinqExtensions.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 
 namespace DHT.Utils.Collections {
 	public static class LinqExtensions {
@@ -14,5 +15,9 @@ namespace DHT.Utils.Collections {
 				}
 			}
 		}
+
+		public static Dictionary<TKey, TValue> ToDictionary<TKey, TValue>(this IEnumerable<(TKey, TValue)> collection) where TKey : notnull {
+			return collection.ToDictionary(static item => item.Item1, static item => item.Item2);
+		}
 	}
 }

app/Utils/Http/HttpOutput.cs

@@ -0,0 +1,56 @@
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+
+namespace DHT.Utils.Http {
+	public static class HttpOutput {
+		public static IHttpOutput None { get; } = new NoneImpl();
+		
+		private sealed class NoneImpl : IHttpOutput {
+			public Task WriteTo(HttpResponse response) {
+				return Task.CompletedTask;
+			}
+		}
+
+		public sealed class Json : IHttpOutput {
+			private readonly object? obj;
+			
+			public Json(object? obj) {
+				this.obj = obj;
+			}
+
+			public Task WriteTo(HttpResponse response) {
+				return response.WriteAsJsonAsync(obj);
+			}
+		}
+
+		public sealed class File : IHttpOutput {
+			private readonly string? contentType;
+			private readonly byte[] bytes;
+			
+			public File(string? contentType, byte[] bytes) {
+				this.contentType = contentType;
+				this.bytes = bytes;
+			}
+
+			public async Task WriteTo(HttpResponse response) {
+				response.ContentType = contentType ?? string.Empty;
+				await response.Body.WriteAsync(bytes);
+			}
+		}
+
+		public sealed class Redirect : IHttpOutput {
+			private readonly string url;
+			private readonly bool permanent;
+
+			public Redirect(string url, bool permanent) {
+				this.url = url;
+				this.permanent = permanent;
+			}
+
+			public Task WriteTo(HttpResponse response) {
+				response.Redirect(url, permanent);
+				return Task.CompletedTask;
+			}
+		}
+	}
+}

app/Utils/Http/IHttpOutput.cs

@@ -0,0 +1,8 @@
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+
+namespace DHT.Utils.Http {
+	public interface IHttpOutput {
+		Task WriteTo(HttpResponse response);
+	}
+}

app/Utils/Utils.csproj

@@ -17,7 +17,10 @@
     <DebugType>none</DebugType>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="JetBrains.Annotations" Version="10.3.0" />
+    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="JetBrains.Annotations" Version="2022.1.0" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="..\Version.cs" Link="Version.cs" />

app/Version.cs

@@ -7,6 +7,6 @@ using DHT.Utils;
 
 namespace DHT.Utils {
 	static class Version {
-		public const string Tag = "36.0.0.0";
+		public const string Tag = "37.1.0.0";
 	}
 }