Handle request cancellation in the integrated HTTP server

Serve viewer page and JSON data from the integrated HTTP server
2025-09-13 15:32:09 +02:00 · 2024-04-20 17:33:05 +02:00 · 2024-04-20 16:36:44 +02:00
41 changed files with 493 additions and 348 deletions
--- a/app/Desktop/Desktop.csproj
+++ b/app/Desktop/Desktop.csproj
@@ -39,11 +39,6 @@
    <EmbeddedResource Include="Resources/tracker-loader.js">
      <LogicalName>tracker-loader.js</LogicalName>
    </EmbeddedResource>
-    <EmbeddedResource Include="../Resources/Viewer/**">
-      <LogicalName>Viewer\%(RecursiveDir)%(Filename)%(Extension)</LogicalName>
-      <Link>Resources/Viewer/%(RecursiveDir)%(Filename)%(Extension)</Link>
-      <Visible>false</Visible>
-    </EmbeddedResource>
  </ItemGroup>
  
 </Project>
--- a/app/Desktop/Main/MainWindow.axaml.cs
+++ b/app/Desktop/Main/MainWindow.axaml.cs
@@ -1,9 +1,7 @@
 using System;
 using System.Diagnostics.CodeAnalysis;
-using System.IO;
 using System.Threading.Tasks;
 using Avalonia.Controls;
-using DHT.Desktop.Main.Pages;
 using DHT.Utils.Logging;
 using JetBrains.Annotations;

@@ -43,13 +41,5 @@ public sealed partial class MainWindow : Window {
 				Log.Error("Caught exception while disposing window: " + ex);
 			}
 		}
-
-		foreach (var temporaryFile in ViewerPageModel.TemporaryFiles) {
-			try {
-				File.Delete(temporaryFile);
-			} catch (Exception) {
-				// ignored
-			}
-		}
 	}
 }
--- a/app/Desktop/Main/Pages/ViewerPage.axaml
+++ b/app/Desktop/Main/Pages/ViewerPage.axaml
@@ -21,7 +21,6 @@
    <StackPanel Orientation="Vertical" Spacing="20">
        <StackPanel Orientation="Horizontal" VerticalAlignment="Top">
            <Button Command="{Binding OnClickOpenViewer}" Margin="0 0 5 0">Open Viewer</Button>
-            <Button Command="{Binding OnClickSaveViewer}" Margin="5 0 0 0">Save Viewer</Button>
        </StackPanel>
        <controls:MessageFilterPanel DataContext="{Binding FilterModel}" />
        <Expander Header="Database Tools">
--- a/app/Desktop/Main/Pages/ViewerPageModel.cs
+++ b/app/Desktop/Main/Pages/ViewerPageModel.cs
@@ -1,34 +1,22 @@
 using System;
-using System.Collections.Concurrent;
 using System.ComponentModel;
 using System.Diagnostics;
-using System.IO;
-using System.Text;
 using System.Threading.Tasks;
 using System.Web;
 using Avalonia.Controls;
-using Avalonia.Platform.Storage;
 using CommunityToolkit.Mvvm.ComponentModel;
 using DHT.Desktop.Common;
-using DHT.Desktop.Dialogs.File;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Dialogs.Progress;
 using DHT.Desktop.Main.Controls;
 using DHT.Desktop.Server;
 using DHT.Server;
 using DHT.Server.Data.Filters;
-using DHT.Server.Database.Export;
-using static DHT.Desktop.Program;
+using DHT.Server.Service.Viewer;

 namespace DHT.Desktop.Main.Pages;

 sealed partial class ViewerPageModel : ObservableObject, IDisposable {
-	public static readonly ConcurrentBag<string> TemporaryFiles = [];
-
-	private static readonly FilePickerFileType[] ViewerFileTypes = [
-		FileDialogs.CreateFilter("Discord History Viewer", ["html"])
-	];
-
 	public bool DatabaseToolFilterModeKeep { get; set; } = true;
 	public bool DatabaseToolFilterModeRemove { get; set; } = false;

@@ -61,101 +49,18 @@ sealed partial class ViewerPageModel : ObservableObject, IDisposable {

 	public async void OnClickOpenViewer() {
 		try {
-			var fullPath = await PrepareTemporaryViewerFile();
+			string serverUrl = "http://127.0.0.1:" + ServerConfiguration.Port;
+			string serverToken = ServerConfiguration.Token;
+			string sessionId = state.ViewerSessions.Register(new ViewerSession(FilterModel.CreateFilter())).ToString();
 			
-			string jsConstants = $"""
-			                      window.DHT_SERVER_URL = "{HttpUtility.JavaScriptStringEncode("http://127.0.0.1:" + ServerConfiguration.Port)}";
-			                      window.DHT_SERVER_TOKEN = "{HttpUtility.JavaScriptStringEncode(ServerConfiguration.Token)}";
-			                      """;
-
-			await ProgressDialog.ShowIndeterminate(window, "Open Viewer", "Creating viewer...", _ => Task.Run(() => WriteViewerFile(fullPath, jsConstants)));
-			
-			Process.Start(new ProcessStartInfo(fullPath) {
+			Process.Start(new ProcessStartInfo(serverUrl + "/viewer/?token=" + HttpUtility.UrlEncode(serverToken) + "&session=" + HttpUtility.UrlEncode(sessionId)) {
 				UseShellExecute = true
 			});
 		} catch (Exception e) {
-			await Dialog.ShowOk(window, "Open Viewer", "Could not create or save viewer: " + e.Message);
+			await Dialog.ShowOk(window, "Open Viewer", "Could not open viewer: " + e.Message);
 		}
 	}

-	private async Task<string> PrepareTemporaryViewerFile() {
-		return await Task.Run(() => {
-			string rootPath = Path.Combine(Path.GetTempPath(), "DiscordHistoryTracker");
-			string filenameBase = Path.GetFileNameWithoutExtension(state.Db.Path) + "-" + DateTime.Now.ToString("yyyy-MM-dd");
-			string fullPath = Path.Combine(rootPath, filenameBase + ".html");
-			
-			int counter = 0;
-
-			while (File.Exists(fullPath)) {
-				++counter;
-				fullPath = Path.Combine(rootPath, filenameBase + "-" + counter + ".html");
-			}
-
-			TemporaryFiles.Add(fullPath);
-
-			Directory.CreateDirectory(rootPath);
-
-			return fullPath;
-		});
-	}
-
-	public async void OnClickSaveViewer() {
-		string? path = await window.StorageProvider.SaveFile(new FilePickerSaveOptions {
-			Title = "Save Viewer",
-			FileTypeChoices = ViewerFileTypes,
-			SuggestedFileName = Path.GetFileNameWithoutExtension(state.Db.Path) + ".html",
-			SuggestedStartLocation = await FileDialogs.GetSuggestedStartLocation(window, Path.GetDirectoryName(state.Db.Path)),
-		});
-
-		if (path == null) {
-			return;
-		}
-
-		try {
-			await ProgressDialog.ShowIndeterminate(window, "Save Viewer", "Creating viewer...", _ => Task.Run(() => WriteViewerFile(path, string.Empty)));
-		} catch (Exception e) {
-			await Dialog.ShowOk(window, "Save Viewer", "Could not create or save viewer: " + e.Message);
-		}
-	}
-
-	private async Task WriteViewerFile(string path, string jsConstants) {
-		const string ArchiveTag = "/*[ARCHIVE]*/";
-
-		string indexFile = await Resources.ReadTextAsync("Viewer/index.html");
-		string viewerTemplate = indexFile.Replace("/*[CONSTANTS]*/", jsConstants)
-		                                 .Replace("/*[JS]*/", await Resources.ReadJoinedAsync("Viewer/scripts/", '\n'))
-		                                 .Replace("/*[CSS]*/", await Resources.ReadJoinedAsync("Viewer/styles/", '\n'));
-
-		int viewerArchiveTagStart = viewerTemplate.IndexOf(ArchiveTag);
-		int viewerArchiveTagEnd = viewerArchiveTagStart + ArchiveTag.Length;
-
-		string jsonTempFile = path + ".tmp";
-
-		await using (var jsonStream = new FileStream(jsonTempFile, FileMode.Create, FileAccess.ReadWrite, FileShare.Read)) {
-			await ViewerJsonExport.Generate(jsonStream, state.Db, FilterModel.CreateFilter());
-
-			char[] jsonBuffer = new char[Math.Min(32768, jsonStream.Position)];
-			jsonStream.Position = 0;
-
-			await using (var outputStream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.Read))
-			await using (var outputWriter = new StreamWriter(outputStream, Encoding.UTF8)) {
-				await outputWriter.WriteAsync(viewerTemplate[..viewerArchiveTagStart]);
-
-				using (var jsonReader = new StreamReader(jsonStream, Encoding.UTF8)) {
-					int readBytes;
-					while ((readBytes = await jsonReader.ReadAsync(jsonBuffer, 0, jsonBuffer.Length)) > 0) {
-						string jsonChunk = new string(jsonBuffer, 0, readBytes);
-						await outputWriter.WriteAsync(HttpUtility.JavaScriptStringEncode(jsonChunk));
-					}
-				}
-
-				await outputWriter.WriteAsync(viewerTemplate[viewerArchiveTagEnd..]);
-			}
-		}
-
-		File.Delete(jsonTempFile);
-	}
-
 	public async Task OnClickApplyFiltersToDatabase() {
 		var filter = FilterModel.CreateFilter();
 		var messageCount = await ProgressDialog.ShowIndeterminate(window, "Apply Filters", "Counting matching messages...", _ => state.Db.Messages.Count(filter));
--- a/app/Resources/Viewer/index.html
+++ b/app/Resources/Viewer/index.html
@@ -4,14 +4,20 @@
    <meta charset="utf-8">
    <title>Discord Offline History</title>
    
+    <link rel="icon" href="favicon.ico">
+    
+    <link rel="stylesheet" href="styles/main.css">
+    <link rel="stylesheet" href="styles/menu.css">
+    <link rel="stylesheet" href="styles/channels.css">
+    <link rel="stylesheet" href="styles/messages.css">
+    <link rel="stylesheet" href="styles/modal.css">
+    
    <script type="text/javascript">
-		window.DHT_EMBEDDED = "/*[ARCHIVE]*/";
-		/*[CONSTANTS]*/
-		/*[JS]*/
+		const query = new URLSearchParams(location.search);
+		window.DHT_SERVER_TOKEN = query.get("token");
+		window.DHT_SERVER_SESSION = query.get("session");
    </script>
-    <style>
-      /*[CSS]*/
-    </style>
+    <script type="module" src="scripts/bootstrap.mjs"></script>
  </head>
  <body>
    <div id="menu">
@@ -65,7 +71,9 @@
    </div>
    
    <div id="app">
-      <div id="channels"></div>
+      <div id="channels">
+        <div class="loading"></div>
+      </div>
      <div id="messages"></div>
    </div>
    
--- a/app/Resources/Viewer/scripts/bootstrap.js
+++ b/app/Resources/Viewer/scripts/bootstrap.js
@@ -1,39 +0,0 @@
-document.addEventListener("DOMContentLoaded", () => {
-	DISCORD.setup();
-	GUI.setup();
-	
-	GUI.onOptionMessagesPerPageChanged(() => {
-		STATE.setMessagesPerPage(GUI.getOptionMessagesPerPage());
-	});
-	
-	STATE.setMessagesPerPage(GUI.getOptionMessagesPerPage());
-	
-	GUI.onOptMessageFilterChanged(filter => {
-		STATE.setActiveFilter(filter);
-	});
-	
-	GUI.onNavigationButtonClicked(action => {
-		STATE.updateCurrentPage(action);
-	});
-	
-	STATE.onUsersRefreshed(users => {
-		GUI.updateUserList(users);
-	});
-	
-	STATE.onChannelsRefreshed((channels, selected) => {
-		GUI.updateChannelList(channels, selected, STATE.selectChannel);
-	});
-	
-	STATE.onMessagesRefreshed(messages => {
-		GUI.updateNavigation(STATE.getCurrentPage(), STATE.getPageCount());
-		GUI.updateMessageList(messages);
-		GUI.scrollMessagesToTop();
-	});
-	
-	try {
-		STATE.uploadFile(JSON.parse(window.DHT_EMBEDDED));
-	} catch (e) {
-		console.error(e);
-		alert("Could not parse embedded file, see console for details.");
-	}
-});
--- a/app/Resources/Viewer/scripts/bootstrap.mjs
+++ b/app/Resources/Viewer/scripts/bootstrap.mjs
@@ -0,0 +1,59 @@
+import discord from "./discord.mjs";
+import gui from "./gui.mjs";
+import state from "./state.mjs";
+
+window.DISCORD = discord;
+
+document.addEventListener("DOMContentLoaded", () => {
+	discord.setup();
+	gui.setup();
+	
+	gui.onOptionMessagesPerPageChanged(() => {
+		state.setMessagesPerPage(gui.getOptionMessagesPerPage());
+	});
+	
+	state.setMessagesPerPage(gui.getOptionMessagesPerPage());
+	
+	gui.onOptMessageFilterChanged(filter => {
+		state.setActiveFilter(filter);
+	});
+	
+	gui.onNavigationButtonClicked(action => {
+		state.updateCurrentPage(action);
+	});
+	
+	state.onUsersRefreshed(users => {
+		gui.updateUserList(users);
+	});
+	
+	state.onChannelsRefreshed((channels, selected) => {
+		gui.updateChannelList(channels, selected, state.selectChannel);
+	});
+	
+	state.onMessagesRefreshed(messages => {
+		gui.updateNavigation(state.getCurrentPage(), state.getPageCount());
+		gui.updateMessageList(messages);
+		gui.scrollMessagesToTop();
+	});
+	
+	async function loadData() {
+		try {
+			const response = await fetch("/get-viewer-data?token=" + encodeURIComponent(window.DHT_SERVER_TOKEN) + "&session=" + encodeURIComponent(window.DHT_SERVER_SESSION), {
+				method: "GET",
+				headers: {
+					"Content-Type": "application/json",
+				},
+				credentials: "omit",
+				redirect: "error",
+			});
+
+			state.uploadFile(await response.json());
+		} catch (e) {
+			console.error(e);
+			alert("Could not load data, see console for details.");
+			document.querySelector("#channels > div.loading").remove();
+		}
+	}
+	
+	loadData();
+});
--- a/app/Resources/Viewer/scripts/discord.mjs
+++ b/app/Resources/Viewer/scripts/discord.mjs
@@ -1,4 +1,10 @@
-const DISCORD = (function() {
+import discord from "./discord.mjs";
+import dom from "./dom.mjs";
+import template from "./template.mjs";
+import settings from "./settings.mjs";
+import state from "./state.mjs";
+
+export default (function() {
 	const regex = {
 		formatBold: /\*\*([\s\S]+?)\*\*(?!\*)/g,
 		formatItalic1: /\*([\s\S]+?)\*(?!\*)/g,
@@ -35,17 +41,14 @@ const DISCORD = (function() {
 	let templateReaction;
 	let templateReactionCustom;
 	
-	const fileUrlProcessor = function(serverUrl, serverToken) {
-		if (typeof serverUrl === "string" && typeof serverToken === "string") {
-			return url => serverUrl + "/get-downloaded-file/" + encodeURIComponent(url) + "?token=" + encodeURIComponent(serverToken);
+	const fileUrlProcessor = function(serverToken) {
+		if (typeof serverToken === "string") {
+			return url => "/get-downloaded-file/" + encodeURIComponent(url) + "?token=" + encodeURIComponent(serverToken);
 		}
 		else {
 			return url => url;
 		}
-	}(
-		window["DHT_SERVER_URL"],
-		window["DHT_SERVER_TOKEN"]
-	);
+	}(window.DHT_SERVER_TOKEN);
 	
 	const getEmoji = function(name, id, extension) {
 		const tag = ":" + name + ":";
@@ -53,9 +56,9 @@ const DISCORD = (function() {
 	};
 	
 	const processMessageContents = function(contents) {
-		let processed = DOM.escapeHTML(contents.replace(regex.formatUrlNoEmbed, "$1"));
+		let processed = dom.escapeHTML(contents.replace(regex.formatUrlNoEmbed, "$1"));
 		
-		if (SETTINGS.enableFormatting) {
+		if (settings.enableFormatting) {
 			const escapeHtmlMatch = (full, match) => "&#" + match.charCodeAt(0) + ";";
 			
 			processed = processed
@@ -71,13 +74,13 @@ const DISCORD = (function() {
 				.replace(regex.formatStrike, "<s>$1</s>");
 		}
 		
-		const animatedEmojiExtension = SETTINGS.enableAnimatedEmoji ? "gif" : "webp";
+		const animatedEmojiExtension = settings.enableAnimatedEmoji ? "gif" : "webp";
 		
 		// noinspection HtmlUnknownTarget
 		processed = processed
 			.replace(regex.formatUrl, "<a href='$1' target='_blank' rel='noreferrer'>$1</a>")
-			.replace(regex.mentionChannel, (full, match) => "<span class='link mention-chat'>#" + STATE.getChannelName(match) + "</span>")
-			.replace(regex.mentionUser, (full, match) => "<span class='link mention-user' title='#" + (STATE.getUserTag(match) || "????") + "'>@" + STATE.getUserName(match) + "</span>")
+			.replace(regex.mentionChannel, (full, match) => "<span class='link mention-chat'>#" + state.getChannelName(match) + "</span>")
+			.replace(regex.mentionUser, (full, match) => "<span class='link mention-user' title='#" + (state.getUserTag(match) || "????") + "'>@" + state.getUserName(match) + "</span>")
 			.replace(regex.customEmojiStatic, (full, m1, m2) => getEmoji(m1, m2, "webp"))
 			.replace(regex.customEmojiAnimated, (full, m1, m2) => getEmoji(m1, m2, animatedEmojiExtension));
 		
@@ -89,7 +92,7 @@ const DISCORD = (function() {
 	};
 	
 	const getImageEmbed = function(url, image) {
-		if (!SETTINGS.enableImagePreviews) {
+		if (!settings.enableImagePreviews) {
 			return "";
 		}
 		
@@ -109,21 +112,21 @@ const DISCORD = (function() {
 	
 	return {
 		setup() {
-			templateChannelServer = new TEMPLATE([
-				"<div data-channel='{id}'>",
+			templateChannelServer = new template([
+				"<div class='channel' data-channel='{id}'>",
 				"<div class='info' title='{topic}'><strong class='name'>#{name}</strong>{nsfw}<span class='tag'>{msgcount}</span></div>",
 				"<span class='server'>{server.name} ({server.type})</span>",
 				"</div>"
 			].join(""));
 			
-			templateChannelPrivate = new TEMPLATE([
-				"<div data-channel='{id}'>",
+			templateChannelPrivate = new template([
+				"<div class='channel' data-channel='{id}'>",
 				"<div class='info'><strong class='name'>{name}</strong><span class='tag'>{msgcount}</span></div>",
 				"<span class='server'>({server.type})</span>",
 				"</div>"
 			].join(""));
 			
-			templateMessageNoAvatar = new TEMPLATE([
+			templateMessageNoAvatar = new template([
 				"<div>",
 				"<div class='reply-message'>{reply}</div>",
 				"<h2><strong class='username' title='#{user.tag}'>{user.name}</strong><span class='info time'>{timestamp}</span>{edit}{jump}</h2>",
@@ -132,7 +135,7 @@ const DISCORD = (function() {
 				"</div>"
 			].join(""));
 			
-			templateMessageWithAvatar = new TEMPLATE([
+			templateMessageWithAvatar = new template([
 				"<div>",
 				"<div class='reply-message reply-message-with-avatar'>{reply}</div>",
 				"<div class='avatar-wrapper'>",
@@ -147,50 +150,50 @@ const DISCORD = (function() {
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
-			templateUserAvatar = new TEMPLATE([
+			templateUserAvatar = new template([
 				"<img src='{url}' alt=''>"
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
-			templateAttachmentDownload = new TEMPLATE([
+			templateAttachmentDownload = new template([
 				"<a href='{url}' class='embed download'>Download {name}</a>"
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
-			templateEmbedImage = new TEMPLATE([
-				"<a href='{url}' class='embed thumbnail loading'><img src='{src}' alt='' onload='DISCORD.handleImageLoad(this)' onerror='DISCORD.handleImageLoadError(this)'></a><br>"
+			templateEmbedImage = new template([
+				"<a href='{url}' class='embed thumbnail loading'><img src='{src}' alt='' onload='window.DISCORD.handleImageLoad(this)' onerror='window.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>"
+			templateEmbedImageWithSize = new template([
+				"<a href='{url}' class='embed thumbnail loading'><img src='{src}' width='{width}' height='{height}' alt='' onload='window.DISCORD.handleImageLoad(this)' onerror='window.DISCORD.handleImageLoadError(this)'></a><br>"
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
-			templateEmbedRich = new TEMPLATE([
+			templateEmbedRich = new template([
 				"<div class='embed download'><a href='{url}' class='title'>{title}</a><p class='desc'>{description}</p></div>"
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
-			templateEmbedRichNoDescription = new TEMPLATE([
+			templateEmbedRichNoDescription = new template([
 				"<div class='embed download'><a href='{url}' class='title'>{title}</a></div>"
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
-			templateEmbedUrl = new TEMPLATE([
+			templateEmbedUrl = new template([
 				"<a href='{url}' class='embed download'>{url}</a>"
 			].join(""));
 			
-			templateEmbedUnsupported = new TEMPLATE([
+			templateEmbedUnsupported = new template([
 				"<div class='embed download'><p>(Unsupported embed)</p></div>"
 			].join(""));
 			
-			templateReaction = new TEMPLATE([
+			templateReaction = new template([
 				"<span class='reaction-wrapper'><span class='reaction-emoji'>{n}</span><span class='count'>{c}</span></span>"
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
-			templateReactionCustom = new TEMPLATE([
+			templateReactionCustom = new template([
 				"<span class='reaction-wrapper'><img src='{url}' alt=':{n}:' title=':{n}:' class='reaction-emoji-custom'><span class='count'>{c}</span></span>"
 			].join(""));
 		},
@@ -207,7 +210,7 @@ const DISCORD = (function() {
 		},
 		
 		isImageAttachment(attachment) {
-			const url = DOM.tryParseUrl(attachment.url);
+			const url = dom.tryParseUrl(attachment.url);
 			return url != null && isImageUrl(url);
 		},
 		
@@ -220,7 +223,7 @@ const DISCORD = (function() {
 		},
 		
 		getMessageHTML(message) { // noinspection FunctionWithInconsistentReturnsJS
-			return (SETTINGS.enableUserAvatars ? templateMessageWithAvatar : templateMessageNoAvatar).apply(message, (property, value) => {
+			return (settings.enableUserAvatars ? templateMessageWithAvatar : templateMessageNoAvatar).apply(message, (property, value) => {
 				if (property === "avatar") {
 					return value ? templateUserAvatar.apply(getAvatarUrlObject(value)) : "";
 				}
@@ -228,7 +231,7 @@ const DISCORD = (function() {
 					return value ? value : "????";
 				}
 				else if (property === "timestamp") {
-					return DOM.getHumanReadableTime(value);
+					return dom.getHumanReadableTime(value);
 				}
 				else if (property === "contents") {
 					return value && value.length > 0 ? processMessageContents(value) : "";
@@ -267,7 +270,7 @@ const DISCORD = (function() {
 					return value.map(attachment => {
 						const url = fileUrlProcessor(attachment.url);
 						
-						if (!DISCORD.isImageAttachment(attachment) || !SETTINGS.enableImagePreviews) {
+						if (!discord.isImageAttachment(attachment) || !settings.enableImagePreviews) {
 							return templateAttachmentDownload.apply({ url, name: attachment.name });
 						}
 						else if ("width" in attachment && "height" in attachment) {
@@ -279,10 +282,10 @@ const DISCORD = (function() {
 					}).join("");
 				}
 				else if (property === "edit") {
-					return value ? "<span class='info edited'>Edited " + DOM.getHumanReadableTime(value) + "</span>" : "";
+					return value ? "<span class='info edited'>Edited " + dom.getHumanReadableTime(value) + "</span>" : "";
 				}
 				else if (property === "jump") {
-					return STATE.hasActiveFilter ? "<span class='info jump' data-jump='" + value + "'>Jump to message</span>" : "";
+					return state.hasActiveFilter ? "<span class='info jump' data-jump='" + value + "'>Jump to message</span>" : "";
 				}
 				else if (property === "reply") {
 					if (!value) {
@@ -290,7 +293,7 @@ const DISCORD = (function() {
 					}
 					
 					const user = "<span class='reply-username' title='#" + (value.user.tag ? value.user.tag : "????") + "'>" + value.user.name + "</span>";
-					const avatar = SETTINGS.enableUserAvatars && value.avatar ? "<span class='reply-avatar'>" + templateUserAvatar.apply(getAvatarUrlObject(value.avatar)) + "</span>" : "";
+					const avatar = settings.enableUserAvatars && value.avatar ? "<span class='reply-avatar'>" + templateUserAvatar.apply(getAvatarUrlObject(value.avatar)) + "</span>" : "";
 					const contents = value.contents ? "<span class='reply-contents'>" + processMessageContents(value.contents) + "</span>" : "";
 					
 					return "<span class='jump' data-jump='" + value.id + "'>Jump to reply</span><span class='user'>" + avatar + user + "</span>" + contents;
@@ -302,7 +305,7 @@ const DISCORD = (function() {
 					
 					return "<div class='reactions'>" + value.map(reaction => {
 						if ("id" in reaction){
-							const ext = reaction.a && SETTINGS.enableAnimatedEmoji ? "gif" : "webp";
+							const ext = reaction.a && settings.enableAnimatedEmoji ? "gif" : "webp";
 							const url = fileUrlProcessor("https://cdn.discordapp.com/emojis/" + reaction.id + "." + ext);
 							// noinspection JSUnusedGlobalSymbols
 							return templateReactionCustom.apply({ url, n: reaction.n, c: reaction.c });
--- a/app/Resources/Viewer/scripts/dom.mjs
+++ b/app/Resources/Viewer/scripts/dom.mjs
@@ -8,9 +8,12 @@ const HTML_ENTITY_MAP = {

 const HTML_ENTITY_REGEX = /[&<>"']/g;

-class DOM {
+export default class {
 	/**
 	 * Returns a child element by its ID. Parent defaults to the entire document.
+	 * @param {string} id
+	 * @param {HTMLElement} [parent]
+	 * @returns {HTMLElement|null}
 	 */
 	static id(id, parent) {
 		return (parent || document).getElementById(id);
@@ -18,6 +21,9 @@ class DOM {
 	
 	/**
 	 * Returns an array of all child elements containing the specified class. Parent defaults to the entire document.
+	 * @param {string} cls
+	 * @param {HTMLElement} [parent]
+	 * @returns {HTMLElement[]}
 	 */
 	static cls(cls, parent) {
 		return Array.prototype.slice.call((parent || document).getElementsByClassName(cls));
@@ -25,6 +31,9 @@ class DOM {
 	
 	/**
 	 * Returns an array of all child elements that have the specified tag. Parent defaults to the entire document.
+	 * @param {string} tag
+	 * @param {HTMLElement} [parent]
+	 * @returns {HTMLElement[]}
 	 */
 	static tag(tag, parent) {
 		return Array.prototype.slice.call((parent || document).getElementsByTagName(tag));
@@ -32,6 +41,9 @@ class DOM {
 	
 	/**
 	 * Returns the first child element containing the specified class. Parent defaults to the entire document.
+	 * @param {string} cls
+	 * @param {HTMLElement} [parent]
+	 * @returns {HTMLElement}
 	 */
 	static fcls(cls, parent) {
 		return (parent || document).getElementsByClassName(cls)[0];
--- a/app/Resources/Viewer/scripts/gui.mjs
+++ b/app/Resources/Viewer/scripts/gui.mjs
@@ -1,10 +1,16 @@
-const GUI = (function() {
+import dom from "./dom.mjs";
+import discord from "./discord.mjs";
+import settings from "./settings.mjs";
+import state from "./state.mjs";
+
+export default (function() {
 	let eventOnOptMessagesPerPageChanged;
 	let eventOnOptMessageFilterChanged;
 	let eventOnNavButtonClicked;
 	
 	const getActiveFilter = function() {
-		const active = DOM.fcls("active", DOM.id("opt-filter-list"));
+		/** @type HTMLSelectElement */
+		const active = dom.fcls("active", dom.id("opt-filter-list"));
 		
 		return active && active.value !== "" ? {
 			"type": active.getAttribute("data-filter-type"),
@@ -17,12 +23,12 @@ const GUI = (function() {
 	};
 	
 	const showModal = function(width, html) {
-		const dialog = DOM.id("dialog");
+		const dialog = dom.id("dialog");
 		dialog.innerHTML = html;
 		dialog.style.width = width + "px";
 		dialog.style.marginLeft = (-width / 2) + "px";
 		
-		DOM.id("modal").classList.add("visible");
+		dom.id("modal").classList.add("visible");
 		return dialog;
 	};
 	
@@ -38,9 +44,9 @@ const GUI = (function() {
 <label><input id='dht-cfg-animemoji' type='checkbox'> Animated Emoji</label><br>`);
 		
 		const setupCheckBox = function(id, settingName) {
-			const ele = DOM.id(id);
-			ele.checked = SETTINGS[settingName];
-			ele.addEventListener("change", () => SETTINGS[settingName] = ele.checked);
+			const ele = dom.id(id);
+			ele.checked = settings[settingName];
+			ele.addEventListener("change", () => settings[settingName] = ele.checked);
 		};
 		
 		setupCheckBox("dht-cfg-imgpreviews", "enableImagePreviews");
@@ -65,20 +71,20 @@ const GUI = (function() {
 		// ---------
 		
 		setup() {
-			const inputMessageFilter = DOM.id("opt-messages-filter");
-			const containerFilterList = DOM.id("opt-filter-list");
+			const inputMessageFilter = dom.id("opt-messages-filter");
+			const containerFilterList = dom.id("opt-filter-list");
 			
 			const resetActiveFilter = function() {
 				inputMessageFilter.value = "";
 				inputMessageFilter.dispatchEvent(new Event("change"));
 				
-				DOM.id("opt-filter-contents").value = "";
+				dom.id("opt-filter-contents").value = "";
 			};
 			
 			inputMessageFilter.value = ""; // required to prevent browsers from remembering old value
 			
 			inputMessageFilter.addEventListener("change", () => {
-				DOM.cls("active", containerFilterList).forEach(ele => ele.classList.remove("active"));
+				dom.cls("active", containerFilterList).forEach(ele => ele.classList.remove("active"));
 				
 				if (inputMessageFilter.value) {
 					containerFilterList.querySelector("[data-filter-type='" + inputMessageFilter.value + "']").classList.add("active");
@@ -91,11 +97,11 @@ const GUI = (function() {
 				ele.addEventListener(ele.tagName === "SELECT" ? "change" : "input", () => triggerFilterChanged());
 			});
 			
-			DOM.id("opt-messages-per-page").addEventListener("change", () => {
+			dom.id("opt-messages-per-page").addEventListener("change", () => {
 				eventOnOptMessagesPerPageChanged && eventOnOptMessagesPerPageChanged();
 			});
 			
-			DOM.tag("button", DOM.fcls("nav")).forEach(button => {
+			dom.tag("button", dom.fcls("nav")).forEach(button => {
 				button.disabled = true;
 				
 				button.addEventListener("click", () => {
@@ -103,34 +109,34 @@ const GUI = (function() {
 				});
 			});
 			
-			DOM.id("btn-settings").addEventListener("click", () => {
+			dom.id("btn-settings").addEventListener("click", () => {
 				showSettingsModal();
 			});
 			
-			DOM.id("btn-about").addEventListener("click", () => {
+			dom.id("btn-about").addEventListener("click", () => {
 				showInfoModal();
 			});
 			
-			DOM.id("messages").addEventListener("click", e => {
+			dom.id("messages").addEventListener("click", e => {
 				const jump = e.target.getAttribute("data-jump");
 				
 				if (jump) {
 					resetActiveFilter();
 					
-					const index = STATE.navigateToMessage(jump);
+					const index = state.navigateToMessage(jump);
 					
 					if (index === -1) {
 						alert("Message not found.");
 					}
 					else {
-						DOM.id("messages").children[index].scrollIntoView();
+						dom.id("messages").children[index].scrollIntoView();
 					}
 				}
 			});
 			
-			DOM.id("overlay").addEventListener("click", () => {
-				DOM.id("modal").classList.remove("visible");
-				DOM.id("dialog").innerHTML = "";
+			dom.id("overlay").addEventListener("click", () => {
+				dom.id("modal").classList.remove("visible");
+				dom.id("dialog").innerHTML = "";
 			});
 		},
 		
@@ -168,19 +174,19 @@ const GUI = (function() {
 		 */
 		getOptionMessagesPerPage() {
 			/** @type HTMLInputElement */
-			const messagesPerPage = DOM.id("opt-messages-per-page");
+			const messagesPerPage = dom.id("opt-messages-per-page");
 			return parseInt(messagesPerPage.value, 10);
 		},
 		
 		updateNavigation(currentPage, totalPages) {
-			DOM.id("nav-page-current").innerHTML = currentPage;
-			DOM.id("nav-page-total").innerHTML = totalPages || "?";
+			dom.id("nav-page-current").innerHTML = currentPage;
+			dom.id("nav-page-total").innerHTML = totalPages || "?";
 			
-			DOM.id("nav-first").disabled = currentPage === 1;
-			DOM.id("nav-prev").disabled = currentPage === 1;
-			DOM.id("nav-pick").disabled = (totalPages || 0) <= 1;
-			DOM.id("nav-next").disabled = currentPage === (totalPages || 1);
-			DOM.id("nav-last").disabled = currentPage === (totalPages || 1);
+			dom.id("nav-first").disabled = currentPage === 1;
+			dom.id("nav-prev").disabled = currentPage === 1;
+			dom.id("nav-pick").disabled = (totalPages || 0) <= 1;
+			dom.id("nav-next").disabled = currentPage === (totalPages || 1);
+			dom.id("nav-last").disabled = currentPage === (totalPages || 1);
 		},
 		
 		// --------------
@@ -191,7 +197,7 @@ const GUI = (function() {
 		 * Updates the channel list and sets up their click events. The callback is triggered whenever a channel is selected, and takes the channel ID as its argument.
 		 */
 		updateChannelList(channels, selected, callback) {
-			const eleChannels = DOM.id("channels");
+			const eleChannels = dom.id("channels");
 			
 			if (!channels) {
 				eleChannels.innerHTML = "";
@@ -201,11 +207,11 @@ const GUI = (function() {
 					channels = channels.filter(channel => channel.msgcount > 0);
 				}
 				
-				eleChannels.innerHTML = channels.map(channel => DISCORD.getChannelHTML(channel)).join("");
+				eleChannels.innerHTML = channels.map(channel => discord.getChannelHTML(channel)).join("");
 				
 				Array.prototype.forEach.call(eleChannels.children, ele => {
 					ele.addEventListener("click", () => {
-						const currentChannel = DOM.fcls("active", eleChannels);
+						const currentChannel = dom.fcls("active", eleChannels);
 						
 						if (currentChannel) {
 							currentChannel.classList.remove("active");
@@ -224,12 +230,12 @@ const GUI = (function() {
 		},
 		
 		updateMessageList(messages) {
-			DOM.id("messages").innerHTML = messages ? messages.map(message => DISCORD.getMessageHTML(message)).join("") : "";
+			dom.id("messages").innerHTML = messages ? messages.map(message => discord.getMessageHTML(message)).join("") : "";
 		},
 		
 		updateUserList(users) {
 			/** @type HTMLSelectElement */
-			const eleSelect = DOM.id("opt-filter-user");
+			const eleSelect = dom.id("opt-filter-user");
 			
 			while (eleSelect.length > 1) {
 				eleSelect.remove(1);
@@ -249,7 +255,7 @@ const GUI = (function() {
 		},
 		
 		scrollMessagesToTop() {
-			DOM.id("messages").scrollTop = 0;
+			dom.id("messages").scrollTop = 0;
 		}
 	};
 })();
--- a/app/Resources/Viewer/scripts/processor.mjs
+++ b/app/Resources/Viewer/scripts/processor.mjs
@@ -1,16 +1,16 @@
-const PROCESSOR = {};
+import discord from "./discord.mjs";

 // ------------------------
 // Global filter generators
 // ------------------------

-PROCESSOR.FILTER = {
+const filter = {
 	byUser: ((userindex) => message => message.u === userindex),
 	byTime: ((timeStart, timeEnd) => message => message.t >= timeStart && message.t <= timeEnd),
 	byContents: ((substr) => message => ("m" in message ? message.m : "").indexOf(substr) !== -1),
 	byRegex: ((regex) => message => regex.test("m" in message ? message.m : "")),
-	withImages: (() => message => (message.e && message.e.some(embed => embed.type === "image")) || (message.a && message.a.some(DISCORD.isImageAttachment))),
-	withDownloads: (() => message => message.a && message.a.some(attachment => !DISCORD.isImageAttachment(attachment))),
+	withImages: (() => message => (message.e && message.e.some(embed => embed.type === "image")) || (message.a && message.a.some(discord.isImageAttachment))),
+	withDownloads: (() => message => message.a && message.a.some(attachment => !discord.isImageAttachment(attachment))),
 	withEmbeds: (() => message => message.e && message.e.length > 0),
 	withAttachments: (() => message => message.a && message.a.length > 0),
 	isEdited: (() => message => ("te" in message) ? message.te : (message.f & 1) === 1)
@@ -20,7 +20,7 @@ PROCESSOR.FILTER = {
 // Global sorters
 // --------------

-PROCESSOR.SORTER = {
+const sorter = {
 	oldestToNewest: (key1, key2) => {
 		if (key1.length === key2.length) {
 			return key1 > key2 ? 1 : key1 < key2 ? -1 : 0;
@@ -39,3 +39,8 @@ PROCESSOR.SORTER = {
 		}
 	}
 };
+
+export default {
+	FILTER: filter,
+	SORTER: sorter
+};
--- a/app/Resources/Viewer/scripts/settings.mjs
+++ b/app/Resources/Viewer/scripts/settings.mjs
@@ -1,4 +1,4 @@
-const SETTINGS = (function() {
+export default (function() {
 	/**
 	 * @type {{}}
 	 * @property {Function} onSettingsChanged
--- a/app/Resources/Viewer/scripts/state.mjs
+++ b/app/Resources/Viewer/scripts/state.mjs
@@ -1,5 +1,8 @@
+import settings from "./settings.mjs";
+import processor from "./processor.mjs";
+
 // noinspection FunctionWithInconsistentReturnsJS
-const STATE = (function() {
+export default (function() {
 	/**
 	 * @type {{}}
 	 * @property {{}} users
@@ -173,7 +176,7 @@ const STATE = (function() {
 	};
 	
 	const getMessageChannel = function(id) {
-		for (const [ channel, messages ] of Object.entries(loadedFileData)) {
+		for (const [ channel, messages ] of Object.entries(loadedFileData)) { 
 			if (id in messages) {
 				return channel;
 			}
@@ -313,7 +316,7 @@ const STATE = (function() {
 			triggerChannelsRefreshed();
 			triggerMessagesRefreshed();
 			
-			SETTINGS.onSettingsChanged(() => triggerMessagesRefreshed());
+			settings.onSettingsChanged(() => triggerMessagesRefreshed());
 		},
 		
 		getChannelName(channel) {
@@ -335,7 +338,7 @@ const STATE = (function() {
 			currentPage = 1;
 			selectedChannel = channel;
 			
-			loadedMessages = getFilteredMessageKeys(channel).sort(PROCESSOR.SORTER.oldestToNewest);
+			loadedMessages = getFilteredMessageKeys(channel).sort(processor.SORTER.oldestToNewest);
 			triggerMessagesRefreshed();
 		},
 		
@@ -416,23 +419,23 @@ const STATE = (function() {
 		setActiveFilter(filter) {
 			switch (filter ? filter.type : "") {
 				case "user":
-					filterFunction = PROCESSOR.FILTER.byUser(loadedFileMeta.userindex.indexOf(filter.value));
+					filterFunction = processor.FILTER.byUser(loadedFileMeta.userindex.indexOf(filter.value));
 					break;
 				
 				case "contents":
-					filterFunction = PROCESSOR.FILTER.byContents(filter.value);
+					filterFunction = processor.FILTER.byContents(filter.value);
 					break;
 				
 				case "withimages":
-					filterFunction = PROCESSOR.FILTER.withImages();
+					filterFunction = processor.FILTER.withImages();
 					break;
 				
 				case "withdownloads":
-					filterFunction = PROCESSOR.FILTER.withDownloads();
+					filterFunction = processor.FILTER.withDownloads();
 					break;
 				
 				case "edited":
-					filterFunction = PROCESSOR.FILTER.isEdited();
+					filterFunction = processor.FILTER.isEdited();
 					break;
 				
 				default:
--- a/app/Resources/Viewer/scripts/template.mjs
+++ b/app/Resources/Viewer/scripts/template.mjs
@@ -1,6 +1,8 @@
+import dom from "./dom.mjs";
+
 const TEMPLATE_REGEX = /{([^{}]+?)}/g;

-class TEMPLATE {
+export default class {
 	constructor(contents) {
 		this.contents = contents;
 	};
@@ -11,10 +13,10 @@ class TEMPLATE {
 			
 			if (processor) {
 				const updated = processor(match, value);
-				return typeof updated === "undefined" ? DOM.escapeHTML(value) : updated;
+				return typeof updated === "undefined" ? dom.escapeHTML(value) : updated;
 			}
 			
-			return DOM.escapeHTML(value);
+			return dom.escapeHTML(value);
 		});
 	}
 }
--- a/app/Resources/Viewer/styles/channels.css
+++ b/app/Resources/Viewer/styles/channels.css
@@ -3,18 +3,24 @@
  min-width: 215px;
  max-width: 300px;
  overflow-y: auto;
+  color: #eee;
  background-color: #1c1e22;
+  font-size: 15px;
 }

-#channels > div {
+#channels > div.loading {
+  margin: 0 auto;
+  width: 150px;
+  height: 150px;
+}
+
+#channels > div.channel {
  cursor: pointer;
  padding: 10px 12px;
-  color: #eee;
-  font-size: 15px;
  border-bottom: 1px solid #333333;
 }

-#channels > div:hover, #channels > div.active {
+#channels > div.channel:hover, #channels > div.channel.active {
  background-color: #282b30;
 }

--- a/app/Resources/Viewer/styles/main.css
+++ b/app/Resources/Viewer/styles/main.css
@@ -11,3 +11,20 @@ body {
  display: flex;
  flex-direction: row;
 }
+
+.loading {
+  position: relative;
+  --loading-backdrop: rgba(0, 0, 0, 0);
+}
+
+.loading::after {
+  content: "";
+  background: var(--loading-backdrop)
+  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%;
+}
--- a/app/Resources/Viewer/styles/messages.css
+++ b/app/Resources/Viewer/styles/messages.css
@@ -107,23 +107,11 @@
 }

 .message .thumbnail {
-  position: relative;
+  --loading-backdrop: rgba(0, 0, 0, 0.75);
  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%;
--- a/app/Server/Database/Export/ViewerJsonExport.cs
+++ b/app/Server/Database/Export/ViewerJsonExport.cs
@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text.Json;
+using System.Threading;
 using System.Threading.Tasks;
 using DHT.Server.Data;
 using DHT.Server.Data.Filters;
@@ -10,17 +11,17 @@ using DHT.Utils.Logging;

 namespace DHT.Server.Database.Export;

-public static class ViewerJsonExport {
+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, IDatabaseFile db, MessageFilter? filter = null, CancellationToken cancellationToken = default) {
 		var perf = Log.Start();

 		var includedUserIds = new HashSet<ulong>();
 		var includedChannelIds = new HashSet<ulong>();
 		var includedServerIds = new HashSet<ulong>();

-		var includedMessages = await db.Messages.Get(filter).ToListAsync();
+		var includedMessages = await db.Messages.Get(filter, cancellationToken).ToListAsync(cancellationToken);
 		var includedChannels = new List<Channel>();

 		foreach (var message in includedMessages) {
@@ -28,7 +29,7 @@ public static class ViewerJsonExport {
 			includedChannelIds.Add(message.Channel);
 		}

-		await foreach (var channel in db.Channels.Get()) {
+		await foreach (var channel in db.Channels.Get(cancellationToken)) {
 			if (includedChannelIds.Contains(channel.Id)) {
 				includedChannels.Add(channel);
 				includedServerIds.Add(channel.Server);
@@ -53,7 +54,7 @@ public static class ViewerJsonExport {

 		perf.Step("Generate value object");

-		await JsonSerializer.SerializeAsync(stream, value, ViewerJsonContext.Default.ViewerJson);
+		await JsonSerializer.SerializeAsync(stream, value, ViewerJsonContext.Default.ViewerJson, cancellationToken);

 		perf.Step("Serialize to JSON");
 		perf.End();
--- a/app/Server/Database/Repositories/IChannelRepository.cs
+++ b/app/Server/Database/Repositories/IChannelRepository.cs
@@ -15,7 +15,7 @@ public interface IChannelRepository {
 	
 	Task<long> Count(CancellationToken cancellationToken = default);
 	
-	IAsyncEnumerable<Channel> Get();
+	IAsyncEnumerable<Channel> Get(CancellationToken cancellationToken = default);

 	internal sealed class Dummy : IChannelRepository {
 		public IObservable<long> TotalCount { get; } = Observable.Return(0L);
@@ -28,7 +28,7 @@ public interface IChannelRepository {
 			return Task.FromResult(0L);
 		}

-		public IAsyncEnumerable<Channel> Get() {
+		public IAsyncEnumerable<Channel> Get(CancellationToken cancellationToken) {
 			return AsyncEnumerable.Empty<Channel>();
 		}
 	}
--- a/app/Server/Database/Repositories/IDownloadRepository.cs
+++ b/app/Server/Database/Repositories/IDownloadRepository.cs
@@ -24,7 +24,7 @@ public interface IDownloadRepository {

 	Task<bool> GetDownloadData(string normalizedUrl, Func<Stream, Task> dataProcessor);
 	
-	Task<bool> GetSuccessfulDownloadWithData(string normalizedUrl, Func<Data.Download, Stream, Task> dataProcessor);
+	Task<bool> GetSuccessfulDownloadWithData(string normalizedUrl, Func<Data.Download, Stream, CancellationToken, Task> dataProcessor, CancellationToken cancellationToken = default);

 	IAsyncEnumerable<DownloadItem> PullPendingDownloadItems(int count, DownloadItemFilter filter, CancellationToken cancellationToken = default);
 	
@@ -55,7 +55,7 @@ public interface IDownloadRepository {
 			return Task.FromResult(false);
 		}

-		public Task<bool> GetSuccessfulDownloadWithData(string normalizedUrl, Func<Data.Download, Stream, Task> dataProcessor) {
+		public Task<bool> GetSuccessfulDownloadWithData(string normalizedUrl, Func<Data.Download, Stream, CancellationToken, Task> dataProcessor, CancellationToken cancellationToken) {
 			return Task.FromResult(false);
 		}

--- a/app/Server/Database/Repositories/IMessageRepository.cs
+++ b/app/Server/Database/Repositories/IMessageRepository.cs
@@ -16,7 +16,7 @@ public interface IMessageRepository {
 	
 	Task<long> Count(MessageFilter? filter = null, CancellationToken cancellationToken = default);
 	
-	IAsyncEnumerable<Message> Get(MessageFilter? filter = null);
+	IAsyncEnumerable<Message> Get(MessageFilter? filter = null, CancellationToken cancellationToken = default);
 	
 	IAsyncEnumerable<ulong> GetIds(MessageFilter? filter = null);
 	
@@ -33,7 +33,7 @@ public interface IMessageRepository {
 			return Task.FromResult(0L);
 		}

-		public IAsyncEnumerable<Message> Get(MessageFilter? filter) {
+		public IAsyncEnumerable<Message> Get(MessageFilter? filter, CancellationToken cancellationToken) {
 			return AsyncEnumerable.Empty<Message>();
 		}

--- a/app/Server/Database/Sqlite/Repositories/SqliteChannelRepository.cs
+++ b/app/Server/Database/Sqlite/Repositories/SqliteChannelRepository.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 using System.Threading;
 using System.Threading.Tasks;
 using DHT.Server.Data;
@@ -54,13 +55,13 @@ sealed class SqliteChannelRepository : BaseSqliteRepository, IChannelRepository
 		return await conn.ExecuteReaderAsync("SELECT COUNT(*) FROM channels", static reader => reader?.GetInt64(0) ?? 0L, cancellationToken);
 	}

-	public async IAsyncEnumerable<Channel> Get() {
+	public async IAsyncEnumerable<Channel> Get([EnumeratorCancellation] CancellationToken cancellationToken) {
 		await using var conn = await pool.Take();

 		await using var cmd = conn.Command("SELECT id, server, name, parent_id, position, topic, nsfw FROM channels");
-		await using var reader = await cmd.ExecuteReaderAsync();
+		await using var reader = await cmd.ExecuteReaderAsync(cancellationToken);

-		while (await reader.ReadAsync()) {
+		while (await reader.ReadAsync(cancellationToken)) {
 			yield return new Channel {
 				Id = reader.GetUint64(0),
 				Server = reader.GetUint64(1),
--- a/app/Server/Database/Sqlite/Repositories/SqliteDownloadRepository.cs
+++ b/app/Server/Database/Sqlite/Repositories/SqliteDownloadRepository.cs
@@ -210,7 +210,7 @@ sealed class SqliteDownloadRepository(SqliteConnectionPool pool) : BaseSqliteRep
 		return true;
 	}

-	public async Task<bool> GetSuccessfulDownloadWithData(string normalizedUrl, Func<Data.Download, Stream, Task> dataProcessor) {
+	public async Task<bool> GetSuccessfulDownloadWithData(string normalizedUrl, Func<Data.Download, Stream, CancellationToken, Task> dataProcessor, CancellationToken cancellationToken) {
 		await using var conn = await pool.Take();

 		await using var cmd = conn.Command(
@@ -228,8 +228,8 @@ sealed class SqliteDownloadRepository(SqliteConnectionPool pool) : BaseSqliteRep
 		string? type;
 		long rowid;
 		
-		await using (var reader = await cmd.ExecuteReaderAsync()) {
-			if (!await reader.ReadAsync()) {
+		await using (var reader = await cmd.ExecuteReaderAsync(cancellationToken)) {
+			if (!await reader.ReadAsync(cancellationToken)) {
 				return false;
 			}

@@ -239,7 +239,7 @@ sealed class SqliteDownloadRepository(SqliteConnectionPool pool) : BaseSqliteRep
 		}
 		
 		await using (var blob = new SqliteBlob(conn.InnerConnection, "download_blobs", "blob", rowid, readOnly: true)) {
-			await dataProcessor(new Data.Download(normalizedUrl, downloadUrl, DownloadStatus.Success, type, (ulong) blob.Length), blob);
+			await dataProcessor(new Data.Download(normalizedUrl, downloadUrl, DownloadStatus.Success, type, (ulong) blob.Length), blob, cancellationToken);
 		}

 		return true;
--- a/app/Server/Database/Sqlite/Repositories/SqliteMessageRepository.cs
+++ b/app/Server/Database/Sqlite/Repositories/SqliteMessageRepository.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.Runtime.CompilerServices;
 using System.Threading;
 using System.Threading.Tasks;
 using DHT.Server.Data;
@@ -213,7 +214,7 @@ sealed class SqliteMessageRepository : BaseSqliteRepository, IMessageRepository
 		}
 	}

-	public async IAsyncEnumerable<Message> Get(MessageFilter? filter) {
+	public async IAsyncEnumerable<Message> Get(MessageFilter? filter, [EnumeratorCancellation] CancellationToken cancellationToken) {
 		await using var conn = await pool.Take();

 		const string AttachmentSql =
@@ -269,9 +270,9 @@ sealed class SqliteMessageRepository : BaseSqliteRepository, IMessageRepository
 			 """
 		);

-		await using var reader = await messageCmd.ExecuteReaderAsync();
+		await using var reader = await messageCmd.ExecuteReaderAsync(cancellationToken);

-		while (await reader.ReadAsync()) {
+		while (await reader.ReadAsync(cancellationToken)) {
 			ulong messageId = reader.GetUint64(0);

 			yield return new Message {
--- a/app/Server/Endpoints/BaseEndpoint.cs
+++ b/app/Server/Endpoints/BaseEndpoint.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Net;
 using System.Text.Json;
+using System.Threading;
 using System.Threading.Tasks;
 using DHT.Server.Database;
 using DHT.Utils.Http;
@@ -19,7 +20,9 @@ abstract class BaseEndpoint(IDatabaseFile db) {

 		try {
 			response.StatusCode = (int) HttpStatusCode.OK;
-			await Respond(ctx.Request, response);
+			await Respond(ctx.Request, response, ctx.RequestAborted);
+		} catch (OperationCanceledException) {
+			throw;
 		} catch (HttpException e) {
 			Log.Error(e);
 			response.StatusCode = (int) e.StatusCode;
@@ -35,7 +38,7 @@ abstract class BaseEndpoint(IDatabaseFile db) {
 		}
 	}

-	protected abstract Task Respond(HttpRequest request, HttpResponse response);
+	protected abstract Task Respond(HttpRequest request, HttpResponse response, CancellationToken cancellationToken);

 	protected static async Task<JsonElement> ReadJson(HttpRequest request) {
 		try {
--- a/app/Server/Endpoints/GetDownloadedFileEndpoint.cs
+++ b/app/Server/Endpoints/GetDownloadedFileEndpoint.cs
@@ -1,4 +1,7 @@
+using System;
+using System.IO;
 using System.Net;
+using System.Threading;
 using System.Threading.Tasks;
 using DHT.Server.Database;
 using DHT.Server.Download;
@@ -8,12 +11,16 @@ using Microsoft.AspNetCore.Http;
 namespace DHT.Server.Endpoints;

 sealed class GetDownloadedFileEndpoint(IDatabaseFile db) : BaseEndpoint(db) {
-	protected override async Task Respond(HttpRequest request, HttpResponse response) {
+	protected override async Task Respond(HttpRequest request, HttpResponse response, CancellationToken cancellationToken) {
 		string url = WebUtility.UrlDecode((string) request.RouteValues["url"]!);
 		string normalizedUrl = DiscordCdn.NormalizeUrl(url);
 		
-		if (!await Db.Downloads.GetSuccessfulDownloadWithData(normalizedUrl, (download, stream) => response.WriteStreamAsync(download.Type, download.Size, stream))) {
+		if (!await Db.Downloads.GetSuccessfulDownloadWithData(normalizedUrl, WriteDataTo(response), cancellationToken)) {
 			response.Redirect(url, permanent: false);
 		}
 	}
+	
+	private static Func<Data.Download, Stream, CancellationToken, Task> WriteDataTo(HttpResponse response) {
+		return (download, stream, cancellationToken) => response.WriteStreamAsync(download.Type, download.Size, stream, cancellationToken);
+	}
 }
--- a/app/Server/Endpoints/GetTrackingScriptEndpoint.cs
+++ b/app/Server/Endpoints/GetTrackingScriptEndpoint.cs
@@ -1,5 +1,5 @@
 using System.Net.Mime;
-using System.Reflection;
+using System.Threading;
 using System.Threading.Tasks;
 using System.Web;
 using DHT.Server.Database;
@@ -10,19 +10,17 @@ using Microsoft.AspNetCore.Http;

 namespace DHT.Server.Endpoints;

-sealed class GetTrackingScriptEndpoint(IDatabaseFile db, ServerParameters parameters) : BaseEndpoint(db) {
-	private static ResourceLoader Resources { get; } = new (Assembly.GetExecutingAssembly());
-
-	protected override async Task Respond(HttpRequest request, HttpResponse response) {
-		string bootstrap = await Resources.ReadTextAsync("Tracker/bootstrap.js");
+sealed class GetTrackingScriptEndpoint(IDatabaseFile db, ServerParameters parameters, ResourceLoader resources) : BaseEndpoint(db) {
+	protected override async Task Respond(HttpRequest request, HttpResponse response, CancellationToken cancellationToken) {
+		string bootstrap = await resources.ReadTextAsync("Tracker/bootstrap.js");
 		string script = bootstrap.Replace("= 0; /*[PORT]*/", "= " + parameters.Port + ";")
 		                         .Replace("/*[TOKEN]*/", HttpUtility.JavaScriptStringEncode(parameters.Token))
-		                         .Replace("/*[IMPORTS]*/", await Resources.ReadJoinedAsync("Tracker/scripts/", '\n'))
-		                         .Replace("/*[CSS-CONTROLLER]*/", await Resources.ReadTextAsync("Tracker/styles/controller.css"))
-		                         .Replace("/*[CSS-SETTINGS]*/", await Resources.ReadTextAsync("Tracker/styles/settings.css"))
+		                         .Replace("/*[IMPORTS]*/", await resources.ReadJoinedAsync("Tracker/scripts/", '\n'))
+		                         .Replace("/*[CSS-CONTROLLER]*/", await resources.ReadTextAsync("Tracker/styles/controller.css"))
+		                         .Replace("/*[CSS-SETTINGS]*/", await resources.ReadTextAsync("Tracker/styles/settings.css"))
 		                         .Replace("/*[DEBUGGER]*/", request.Query.ContainsKey("debug") ? "debugger;" : "");
 		
 		response.Headers.Append("X-DHT", "1");
-		await response.WriteTextAsync(MediaTypeNames.Text.JavaScript, script);
+		await response.WriteTextAsync(MediaTypeNames.Text.JavaScript, script, cancellationToken);
 	}
 }
--- a/app/Server/Endpoints/GetViewerDataEndpoint.cs
+++ b/app/Server/Endpoints/GetViewerDataEndpoint.cs
@@ -0,0 +1,25 @@
+using System;
+using System.Net;
+using System.Net.Mime;
+using System.Threading;
+using System.Threading.Tasks;
+using DHT.Server.Database;
+using DHT.Server.Database.Export;
+using DHT.Server.Service.Viewer;
+using DHT.Utils.Http;
+using Microsoft.AspNetCore.Http;
+
+namespace DHT.Server.Endpoints; 
+
+sealed class GetViewerDataEndpoint(IDatabaseFile db, ViewerSessions viewerSessions) : BaseEndpoint(db) {
+	protected override Task Respond(HttpRequest request, HttpResponse response, CancellationToken cancellationToken) {
+		if (!request.Query.TryGetValue("session", out var sessionIdValue) || sessionIdValue.Count != 1 || !Guid.TryParse(sessionIdValue[0], out Guid sessionId)) {
+			throw new HttpException(HttpStatusCode.BadRequest, "Invalid session ID.");
+		}
+		
+		response.ContentType = MediaTypeNames.Application.Json;
+		
+		var session = viewerSessions.Get(sessionId);
+		return ViewerJsonExport.Generate(response.Body, Db, session.MessageFilter, cancellationToken);
+	}
+}
--- a/app/Server/Endpoints/TrackChannelEndpoint.cs
+++ b/app/Server/Endpoints/TrackChannelEndpoint.cs
@@ -1,5 +1,6 @@
 using System.Net;
 using System.Text.Json;
+using System.Threading;
 using System.Threading.Tasks;
 using DHT.Server.Data;
 using DHT.Server.Database;
@@ -9,7 +10,7 @@ using Microsoft.AspNetCore.Http;
 namespace DHT.Server.Endpoints;

 sealed class TrackChannelEndpoint(IDatabaseFile db) : BaseEndpoint(db) {
-	protected override async Task Respond(HttpRequest request, HttpResponse response) {
+	protected override async Task Respond(HttpRequest request, HttpResponse response, CancellationToken cancellationToken) {
 		var root = await ReadJson(request);
 		var server = ReadServer(root.RequireObject("server"), "server");
 		var channel = ReadChannel(root.RequireObject("channel"), "channel", server.Id);
--- a/app/Server/Endpoints/TrackMessagesEndpoint.cs
+++ b/app/Server/Endpoints/TrackMessagesEndpoint.cs
@@ -4,6 +4,7 @@ using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Net;
 using System.Text.Json;
+using System.Threading;
 using System.Threading.Tasks;
 using DHT.Server.Data;
 using DHT.Server.Data.Filters;
@@ -19,7 +20,7 @@ sealed class TrackMessagesEndpoint(IDatabaseFile db) : BaseEndpoint(db) {
 	private const string HasNewMessages = "1";
 	private const string NoNewMessages = "0";

-	protected override async Task Respond(HttpRequest request, HttpResponse response) {
+	protected override async Task Respond(HttpRequest request, HttpResponse response, CancellationToken cancellationToken) {
 		var root = await ReadJson(request);

 		if (root.ValueKind != JsonValueKind.Array) {
@@ -37,11 +38,11 @@ sealed class TrackMessagesEndpoint(IDatabaseFile db) : BaseEndpoint(db) {
 		}

 		var addedMessageFilter = new MessageFilter { MessageIds = addedMessageIds };
-		bool anyNewMessages = await Db.Messages.Count(addedMessageFilter) < addedMessageIds.Count;
+		bool anyNewMessages = await Db.Messages.Count(addedMessageFilter, CancellationToken.None) < addedMessageIds.Count;

 		await Db.Messages.Add(messages);

-		await response.WriteTextAsync(anyNewMessages ? HasNewMessages : NoNewMessages);
+		await response.WriteTextAsync(anyNewMessages ? HasNewMessages : NoNewMessages, cancellationToken);
 	}

 	private static Message ReadMessage(JsonElement json, string path) => new () {
--- a/app/Server/Endpoints/TrackUsersEndpoint.cs
+++ b/app/Server/Endpoints/TrackUsersEndpoint.cs
@@ -1,5 +1,6 @@
 using System.Net;
 using System.Text.Json;
+using System.Threading;
 using System.Threading.Tasks;
 using DHT.Server.Data;
 using DHT.Server.Database;
@@ -9,7 +10,7 @@ using Microsoft.AspNetCore.Http;
 namespace DHT.Server.Endpoints;

 sealed class TrackUsersEndpoint(IDatabaseFile db) : BaseEndpoint(db) {
-	protected override async Task Respond(HttpRequest request, HttpResponse response) {
+	protected override async Task Respond(HttpRequest request, HttpResponse response, CancellationToken cancellationToken) {
 		var root = await ReadJson(request);

 		if (root.ValueKind != JsonValueKind.Array) {
--- a/app/Server/Endpoints/ViewerEndpoint.cs
+++ b/app/Server/Endpoints/ViewerEndpoint.cs
@@ -0,0 +1,42 @@
+using System.Collections.Generic;
+using System.Net;
+using System.Threading;
+using System.Threading.Tasks;
+using DHT.Server.Database;
+using DHT.Utils.Http;
+using DHT.Utils.Resources;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.StaticFiles;
+
+namespace DHT.Server.Endpoints;
+
+sealed class ViewerEndpoint(IDatabaseFile db, ResourceLoader resources) : BaseEndpoint(db) {
+	private static readonly FileExtensionContentTypeProvider ContentTypeProvider = new ();
+
+	private readonly Dictionary<string, byte[]?> cache = new ();
+	private readonly SemaphoreSlim cacheSemaphore = new (1);
+
+	protected override async Task Respond(HttpRequest request, HttpResponse response, CancellationToken cancellationToken) {
+		string path = (string?) request.RouteValues["path"] ?? "index.html";
+		string resourcePath = "Viewer/" + path;
+		
+		byte[]? resourceBytes;
+
+		await cacheSemaphore.WaitAsync(cancellationToken);
+		try {
+			if (!cache.TryGetValue(resourcePath, out resourceBytes)) {
+				cache[resourcePath] = resourceBytes = await resources.ReadBytesAsyncIfExists(resourcePath);
+			}
+		} finally {
+			cacheSemaphore.Release();
+		}
+
+		if (resourceBytes == null) {
+			throw new HttpException(HttpStatusCode.NotFound, "File not found: " + path);
+		}
+		else {
+			var contentType = ContentTypeProvider.TryGetContentType(path, out string? type) ? type : null;
+			await response.WriteFileAsync(contentType, resourceBytes, cancellationToken);
+		}
+	}
+}
--- a/app/Server/Server.csproj
+++ b/app/Server/Server.csproj
@@ -39,6 +39,16 @@
      <Link>Resources/Tracker/styles/%(RecursiveDir)%(Filename)%(Extension)</Link>
      <Visible>false</Visible>
    </EmbeddedResource>
+    <EmbeddedResource Include="../Resources/Viewer/**">
+      <LogicalName>Viewer\%(RecursiveDir)%(Filename)%(Extension)</LogicalName>
+      <Link>Resources/Viewer/%(RecursiveDir)%(Filename)%(Extension)</Link>
+      <Visible>false</Visible>
+    </EmbeddedResource>
+    <EmbeddedResource Include="../Desktop/Resources/icon.ico">
+      <LogicalName>Viewer\favicon.ico</LogicalName>
+      <Link>Resources/icon.ico</Link>
+      <Visible>false</Visible>
+    </EmbeddedResource>
  </ItemGroup>
  
 </Project>
--- a/app/Server/Service/Middlewares/ServerLoggingMiddleware.cs
+++ b/app/Server/Service/Middlewares/ServerLoggingMiddleware.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Diagnostics;
 using System.Threading.Tasks;
 using DHT.Utils.Logging;
@@ -6,24 +7,34 @@ using Microsoft.AspNetCore.Http.Extensions;

 namespace DHT.Server.Service.Middlewares;

-sealed class ServerLoggingMiddleware {
+sealed class ServerLoggingMiddleware(RequestDelegate next) {
 	private static readonly Log Log = Log.ForType<ServerLoggingMiddleware>();
-	
-	private readonly RequestDelegate next;
-	
-	public ServerLoggingMiddleware(RequestDelegate next) {
-		this.next = next;
-	}

 	public async Task InvokeAsync(HttpContext context) {
 		var stopwatch = Stopwatch.StartNew();
-		await next(context);
+		try {
+			await next(context);
+		} catch (OperationCanceledException) {
+			OnFinished(stopwatch, context);
+			throw;
+		}
+
+		OnFinished(stopwatch, context);
+	}
+
+	private static void OnFinished(Stopwatch stopwatch, HttpContext context) {
 		stopwatch.Stop();
-		
+
 		var request = context.Request;
 		var requestLength = request.ContentLength ?? 0L;
-		var responseStatus = context.Response.StatusCode;
 		var elapsedMs = stopwatch.ElapsedMilliseconds;
-		Log.Debug("Request to " + request.GetEncodedPathAndQuery() + " (" + requestLength + " B) returned " + responseStatus + ", took " + elapsedMs + " ms");
+
+		if (context.RequestAborted.IsCancellationRequested) {
+			Log.Debug("Request to " + request.GetEncodedPathAndQuery() + " (" + requestLength + " B) was cancelled after " + elapsedMs + " ms");
+		}
+		else {
+			var responseStatus = context.Response.StatusCode;
+			Log.Debug("Request to " + request.GetEncodedPathAndQuery() + " (" + requestLength + " B) returned " + responseStatus + ", took " + elapsedMs + " ms");
+		}
 	}
 }
--- a/app/Server/Service/ServerManager.cs
+++ b/app/Server/Service/ServerManager.cs
@@ -1,8 +1,11 @@
 using System;
+using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
 using DHT.Server.Database;
+using DHT.Server.Service.Viewer;
 using DHT.Utils.Logging;
+using DHT.Utils.Resources;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Server.Kestrel.Core;
 using Microsoft.Extensions.DependencyInjection;
@@ -25,10 +28,12 @@ public sealed class ServerManager {
 	}

 	private readonly IDatabaseFile db;
+	private readonly ViewerSessions viewerSessions;
 	private readonly SemaphoreSlim semaphore = new (1, 1);

-	internal ServerManager(IDatabaseFile db) {
+	internal ServerManager(IDatabaseFile db, ViewerSessions viewerSessions) {
 		this.db = db;
+		this.viewerSessions = viewerSessions;
 	}

 	public async Task Start(ushort port, string token) {
@@ -57,6 +62,8 @@ public sealed class ServerManager {
 		void AddServices(IServiceCollection services) {
 			services.AddSingleton(typeof(IDatabaseFile), db);
 			services.AddSingleton(typeof(ServerParameters), new ServerParameters(port, token));
+			services.AddSingleton(typeof(ResourceLoader), new ResourceLoader(Assembly.GetExecutingAssembly()));
+			services.AddSingleton(typeof(ViewerSessions), viewerSessions);
 		}

 		void SetKestrelOptions(KestrelServerOptions options) {
--- a/app/Server/Service/ServerStartup.cs
+++ b/app/Server/Service/ServerStartup.cs
@@ -3,6 +3,8 @@ using System.Text.Json.Serialization;
 using DHT.Server.Database;
 using DHT.Server.Endpoints;
 using DHT.Server.Service.Middlewares;
+using DHT.Server.Service.Viewer;
+using DHT.Utils.Resources;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http.Json;
 using Microsoft.Extensions.DependencyInjection;
@@ -33,14 +35,23 @@ sealed class Startup {
 	}

 	[SuppressMessage("ReSharper", "UnusedMember.Global")]
-	public void Configure(IApplicationBuilder app, IHostApplicationLifetime lifetime, IDatabaseFile db, ServerParameters parameters) {
+	public void Configure(IApplicationBuilder app, IHostApplicationLifetime lifetime, IDatabaseFile db, ServerParameters parameters, ResourceLoader resources, ViewerSessions viewerSessions) {
 		app.UseMiddleware<ServerLoggingMiddleware>();
 		app.UseCors();
-		app.UseMiddleware<ServerAuthorizationMiddleware>();
-		app.UseRouting();
 		
+		app.Map("/viewer", node => {
+			node.UseRouting();
+			node.UseEndpoints(endpoints => {
+				endpoints.MapGet("/{**path}", new ViewerEndpoint(db, resources).Handle);
+			});
+		});
+		
+		app.UseMiddleware<ServerAuthorizationMiddleware>();
+		
+		app.UseRouting();
 		app.UseEndpoints(endpoints => {
-			endpoints.MapGet("/get-tracking-script", new GetTrackingScriptEndpoint(db, parameters).Handle);
+			endpoints.MapGet("/get-tracking-script", new GetTrackingScriptEndpoint(db, parameters, resources).Handle);
+			endpoints.MapGet("/get-viewer-data", new GetViewerDataEndpoint(db, viewerSessions).Handle);
 			endpoints.MapGet("/get-downloaded-file/{url}", new GetDownloadedFileEndpoint(db).Handle);
 			endpoints.MapPost("/track-channel", new TrackChannelEndpoint(db).Handle);
 			endpoints.MapPost("/track-users", new TrackUsersEndpoint(db).Handle);
--- a/app/Server/Service/Viewer/ViewerSession.cs
+++ b/app/Server/Service/Viewer/ViewerSession.cs
@@ -0,0 +1,5 @@
+using DHT.Server.Data.Filters;
+
+namespace DHT.Server.Service.Viewer; 
+
+public readonly record struct ViewerSession(MessageFilter? MessageFilter);
--- a/app/Server/Service/Viewer/ViewerSessions.cs
+++ b/app/Server/Service/Viewer/ViewerSessions.cs
@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+
+namespace DHT.Server.Service.Viewer;
+
+public sealed class ViewerSessions : IDisposable {
+	private readonly Dictionary<Guid, ViewerSession> sessions = new ();
+	private bool isDisposed = false;
+
+	public Guid Register(ViewerSession session) {
+		Guid guid = Guid.NewGuid();
+		
+		lock (this) {
+			ObjectDisposedException.ThrowIf(isDisposed, this);
+			sessions[guid] = session;
+		}
+		
+		return guid;
+	}
+
+	internal ViewerSession Get(Guid guid) {
+		lock (this) {
+			return sessions.GetValueOrDefault(guid);
+		}
+	}
+
+	public void Dispose() {
+		lock (this) {
+			if (!isDisposed) {
+				isDisposed = true;
+				sessions.Clear();
+			}
+		}
+	}
+}
--- a/app/Server/State.cs
+++ b/app/Server/State.cs
@@ -3,19 +3,29 @@ using System.Threading.Tasks;
 using DHT.Server.Database;
 using DHT.Server.Download;
 using DHT.Server.Service;
+using DHT.Server.Service.Viewer;

 namespace DHT.Server;

-public sealed class State(IDatabaseFile db, int? concurrentDownloads) : IAsyncDisposable {
+public sealed class State : IAsyncDisposable {
 	public static State Dummy { get; } = new (DummyDatabaseFile.Instance, null);
-	
-	public IDatabaseFile Db { get; } = db;
-	public Downloader Downloader { get; } = new (db, concurrentDownloads);
-	public ServerManager Server { get; } = new (db);
+
+	public IDatabaseFile Db { get; }
+	public Downloader Downloader { get; }
+	public ViewerSessions ViewerSessions { get; }
+	public ServerManager Server { get; }
+
+	public State(IDatabaseFile db, int? concurrentDownloads) {
+		Db = db;
+		Downloader = new Downloader(db, concurrentDownloads);
+		ViewerSessions = new ViewerSessions();
+		Server = new ServerManager(db, ViewerSessions);
+	}

 	public async ValueTask DisposeAsync() {
 		await Downloader.Stop();
 		await Server.Stop();
 		await Db.DisposeAsync();
+		ViewerSessions.Dispose();
 	}
 }
--- a/app/Utils/Http/HttpExtensions.cs
+++ b/app/Utils/Http/HttpExtensions.cs
@@ -1,33 +1,34 @@
 using System.IO;
 using System.Net.Mime;
 using System.Text;
+using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;

 namespace DHT.Utils.Http; 

 public static class HttpExtensions {
-	public static Task WriteTextAsync(this HttpResponse response, string text) {
-		return WriteTextAsync(response, MediaTypeNames.Text.Plain, text);
+	public static Task WriteTextAsync(this HttpResponse response, string text, CancellationToken cancellationToken) {
+		return WriteTextAsync(response, MediaTypeNames.Text.Plain, text, cancellationToken);
 	}
 	
-	public static async Task WriteTextAsync(this HttpResponse response, string contentType, string text) {
+	public static async Task WriteTextAsync(this HttpResponse response, string contentType, string text, CancellationToken cancellationToken) {
 		response.ContentType = contentType;
-		await response.StartAsync();
-		await response.WriteAsync(text, Encoding.UTF8);
+		await response.StartAsync(cancellationToken);
+		await response.WriteAsync(text, Encoding.UTF8, cancellationToken);
 	}
 	
-	public static async Task WriteFileAsync(this HttpResponse response, string? contentType, byte[] bytes) {
+	public static async Task WriteFileAsync(this HttpResponse response, string? contentType, byte[] bytes, CancellationToken cancellationToken) {
 		response.ContentType = contentType ?? string.Empty;
 		response.ContentLength = bytes.Length;
-		await response.StartAsync();
-		await response.Body.WriteAsync(bytes);
+		await response.StartAsync(cancellationToken);
+		await response.Body.WriteAsync(bytes, cancellationToken);
 	}
 	
-	public static async Task WriteStreamAsync(this HttpResponse response, string? contentType, ulong? contentLength, Stream source) {
+	public static async Task WriteStreamAsync(this HttpResponse response, string? contentType, ulong? contentLength, Stream source, CancellationToken cancellationToken) {
 		response.ContentType = contentType ?? string.Empty;
 		response.ContentLength = (long?) contentLength;
-		await response.StartAsync();
-		await source.CopyToAsync(response.Body);
+		await response.StartAsync(cancellationToken);
+		await source.CopyToAsync(response.Body, cancellationToken);
 	}
 }
--- a/app/Utils/Resources/ResourceLoader.cs
+++ b/app/Utils/Resources/ResourceLoader.cs
@@ -7,8 +7,9 @@ using System.Threading.Tasks;
 namespace DHT.Utils.Resources;

 public sealed class ResourceLoader(Assembly assembly) {
-	private Stream GetEmbeddedStream(string filename) {
+	private Stream? TryGetEmbeddedStream(string filename) {
 		Stream? stream = null;
+		
 		foreach (var embeddedName in assembly.GetManifestResourceNames()) {
 			if (embeddedName.Replace('\\', '/') == filename) {
 				stream = assembly.GetManifestResourceStream(embeddedName);
@@ -16,17 +17,31 @@ public sealed class ResourceLoader(Assembly assembly) {
 			}
 		}

-		return stream ?? throw new ArgumentException("Missing embedded resource: " + filename);
+		return stream;
+	}
+	
+	private Stream GetEmbeddedStream(string filename) {
+		return TryGetEmbeddedStream(filename) ?? throw new ArgumentException("Missing embedded resource: " + filename);
 	}

 	private async Task<string> ReadTextAsync(Stream stream) {
 		using var reader = new StreamReader(stream, Encoding.UTF8);
 		return await reader.ReadToEndAsync();
 	}
+	
+	private async Task<byte[]> ReadBytesAsync(Stream stream) {
+		using var memoryStream = new MemoryStream();
+		await stream.CopyToAsync(memoryStream);
+		return memoryStream.ToArray();
+	}

 	public async Task<string> ReadTextAsync(string filename) {
 		return await ReadTextAsync(GetEmbeddedStream(filename));
 	}
+	
+	public async Task<byte[]?> ReadBytesAsyncIfExists(string filename) {
+		return TryGetEmbeddedStream(filename) is {} stream ? await ReadBytesAsync(stream) : null;
+	}

 	public async Task<string> ReadJoinedAsync(string path, char separator) {
 		StringBuilder joined = new ();
Author	SHA1	Message	Date
chylex	0d5e01532e	Handle request cancellation in the integrated HTTP server	2024-04-20 17:33:05 +02:00
chylex	9094f374f8	Serve viewer page and JSON data from the integrated HTTP server	2024-04-20 16:36:44 +02:00