Refactor

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Directory.Packages.props

@@ -14,7 +14,7 @@
     <PackageVersion Include="CommunityToolkit.Mvvm" Version="8.4.2" />
     <PackageVersion Include="coverlet.collector" Version="10.0.1" />
     <PackageVersion Include="CSharpier.MsBuild" Version="1.2.6" />
-    <PackageVersion Include="Deorcify" Version="1.1.0" />
+    <PackageVersion Include="Deorcify" Version="2.0.1" />
     <PackageVersion Include="DialogHost.Avalonia" Version="0.12.2" />
     <PackageVersion Include="FluentAssertions" Version="8.10.0" />
     <PackageVersion Include="GitHubActionsTestLogger" Version="3.0.4" />
@@ -33,7 +33,7 @@
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
     <PackageVersion Include="Onova" Version="2.6.13" />
     <PackageVersion Include="Polly" Version="8.6.6" />
-    <PackageVersion Include="PowerKit" Version="1.2.0" />
+    <PackageVersion Include="PowerKit" Version="2.0.1" />
     <PackageVersion Include="RazorBlade" Version="1.0.0" />
     <PackageVersion Include="Spectre.Console" Version="0.55.2" />
     <PackageVersion Include="Superpower" Version="3.1.0" />

DiscordChatExporter.Cli.Tests/DiscordChatExporter.Cli.Tests.csproj

@@ -14,13 +14,13 @@
     <PackageReference Include="coverlet.collector" PrivateAssets="all" />
     <PackageReference Include="CSharpier.MsBuild" PrivateAssets="all" />
     <PackageReference Include="FluentAssertions" />
-    <PackageReference Include="GitHubActionsTestLogger" PrivateAssets="all" />
+    <PackageReference Include="GitHubActionsTestLogger" />
     <PackageReference Include="JsonExtensions" />
     <PackageReference Include="Microsoft.Extensions.Configuration" />
     <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" />
     <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" />
-    <PackageReference Include="PowerKit" PrivateAssets="all" />
+    <PackageReference Include="PowerKit" />
     <PackageReference Include="xunit" />
     <PackageReference Include="xunit.runner.visualstudio" PrivateAssets="all" />
   </ItemGroup>

DiscordChatExporter.Cli/Commands/Base/ExportCommandBase.cs

@@ -165,6 +165,37 @@ public abstract class ExportCommandBase : DiscordCommandBase
             throw new CommandException("Option --media-dir cannot be used without --media.");
         }
 
+        // Make sure the user does not try to export multiple channels into one file.
+        // Output path must either be a directory or contain template tokens for this to work.
+        // Validate this up-front, before fetching threads, because thread fetching can take a
+        // long time and it's frustrating to fail only after it completes.
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/799
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/917
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/1549
+        var mayExportMultipleChannels =
+            // Multiple channels were provided explicitly
+            channels.Count > 1
+            // Thread inclusion can add more channels to the export
+            || ThreadInclusionMode != ThreadInclusionMode.None;
+
+        var isValidOutputPath =
+            // Anything is valid when exporting a single channel
+            !mayExportMultipleChannels
+            // When using template tokens, assume the user knows what they're doing
+            || OutputPath.Contains('%')
+            // Otherwise, require an existing directory or an unambiguous directory path
+            || Directory.Exists(OutputPath)
+            || Path.EndsInDirectorySeparator(OutputPath);
+
+        if (!isValidOutputPath)
+        {
+            throw new CommandException(
+                "Attempted to export multiple channels, but the output path is neither a directory nor a template. "
+                    + "If the provided output path is meant to be treated as a directory, make sure it ends with a slash. "
+                    + $"Provided output path: '{OutputPath}'."
+            );
+        }
+
         var unwrappedChannels = new List<Channel>(channels);
 
         // Unwrap threads
@@ -205,28 +236,6 @@ public abstract class ExportCommandBase : DiscordCommandBase
             await console.Output.WriteLineAsync($"Fetched {fetchedThreadsCount} thread(s).");
         }
 
-        // Make sure the user does not try to export multiple channels into one file.
-        // Output path must either be a directory or contain template tokens for this to work.
-        // https://github.com/Tyrrrz/DiscordChatExporter/issues/799
-        // https://github.com/Tyrrrz/DiscordChatExporter/issues/917
-        var isValidOutputPath =
-            // Anything is valid when exporting a single channel
-            unwrappedChannels.Count <= 1
-            // When using template tokens, assume the user knows what they're doing
-            || OutputPath.Contains('%')
-            // Otherwise, require an existing directory or an unambiguous directory path
-            || Directory.Exists(OutputPath)
-            || Path.EndsInDirectorySeparator(OutputPath);
-
-        if (!isValidOutputPath)
-        {
-            throw new CommandException(
-                "Attempted to export multiple channels, but the output path is neither a directory nor a template. "
-                    + "If the provided output path is meant to be treated as a directory, make sure it ends with a slash. "
-                    + $"Provided output path: '{OutputPath}'."
-            );
-        }
-
         // Export
         var errorsByChannel = new ConcurrentDictionary<Channel, string>();
         var warningsByChannel = new ConcurrentDictionary<Channel, string>();

DiscordChatExporter.Cli/DiscordChatExporter.Cli.csproj

@@ -9,9 +9,9 @@
   <ItemGroup>
     <PackageReference Include="CliFx" />
     <PackageReference Include="CSharpier.MsBuild" PrivateAssets="all" />
-    <PackageReference Include="Deorcify" PrivateAssets="all" />
+    <PackageReference Include="Deorcify" />
     <PackageReference Include="Gress" />
-    <PackageReference Include="PowerKit" PrivateAssets="all" />
+    <PackageReference Include="PowerKit" />
     <PackageReference Include="Spectre.Console" />
   </ItemGroup>
 

DiscordChatExporter.Core/Discord/Data/MessageKind.cs

@@ -13,4 +13,5 @@ public enum MessageKind
     GuildMemberJoin = 7,
     ThreadCreated = 18,
     Reply = 19,
+    ThreadStarterMessage = 21,
 }

DiscordChatExporter.Core/Discord/DiscordClient.cs

@@ -30,9 +30,8 @@ public class DiscordClient(
         string url,
         TokenKind tokenKind,
         CancellationToken cancellationToken = default
-    )
-    {
-        return await Http.ResponseResiliencePipeline.ExecuteAsync(
+    ) =>
+        await Http.ResponseResiliencePipeline.ExecuteAsync(
             async innerCancellationToken =>
             {
                 using var request = new HttpRequestMessage(HttpMethod.Get, new Uri(_baseUri, url));
@@ -91,7 +90,6 @@ public class DiscordClient(
             },
             cancellationToken
         );
-    }
 
     private async ValueTask<TokenKind> ResolveTokenKindAsync(
         CancellationToken cancellationToken = default
@@ -364,6 +362,7 @@ public class DiscordClient(
             $"guilds/{guildId}/members/{memberId}",
             cancellationToken
         );
+
         return response?.Pipe(j => Member.Parse(j, guildId));
     }
 
@@ -412,14 +411,12 @@ public class DiscordClient(
             ?.GetNonWhiteSpaceStringOrNull()
             ?.Pipe(Snowflake.Parse);
 
-        Channel? parent = null;
-        if (parentId is not null)
-        {
-            // It's possible for the parent channel to be inaccessible, despite the
-            // child channel being accessible.
-            // https://github.com/Tyrrrz/DiscordChatExporter/issues/1108
-            parent = await TryGetChannelAsync(parentId.Value, cancellationToken);
-        }
+        // It's possible for the parent channel to be inaccessible, despite the
+        // child channel being accessible.
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/1108
+        var parent = parentId is not null
+            ? await TryGetChannelAsync(parentId.Value, cancellationToken)
+            : null;
 
         return Channel.Parse(response.Value, parent);
     }
@@ -607,8 +604,12 @@ public class DiscordClient(
             .SetQueryParameter("after", (after ?? Snowflake.Zero).ToString())
             .Build();
 
-        var response = await GetJsonResponseAsync(url, cancellationToken);
-        var message = response.EnumerateArray().Select(Message.Parse).FirstOrDefault();
+        // Can be null on channels that the user cannot access
+        var response = await TryGetJsonResponseAsync(url, cancellationToken);
+        if (response is null)
+            return null;
+
+        var message = response.Value.EnumerateArray().Select(Message.Parse).FirstOrDefault();
 
         return message;
     }
@@ -625,8 +626,39 @@ public class DiscordClient(
             .SetQueryParameter("before", before?.ToString())
             .Build();
 
-        var response = await GetJsonResponseAsync(url, cancellationToken);
-        return response.EnumerateArray().Select(Message.Parse).LastOrDefault();
+        // Can be null on channels that the user cannot access
+        var response = await TryGetJsonResponseAsync(url, cancellationToken);
+        if (response is null)
+            return null;
+
+        return response.Value.EnumerateArray().Select(Message.Parse).LastOrDefault();
+    }
+
+    public async ValueTask<Message?> TryGetMessageAsync(
+        Snowflake channelId,
+        Snowflake messageId,
+        CancellationToken cancellationToken = default
+    )
+    {
+        // Use the regular message listing endpoint with the 'around' parameter instead of the
+        // dedicated single-message endpoint, because the latter is not accessible to user tokens.
+        var url = new UrlBuilder()
+            .SetPath($"channels/{channelId}/messages")
+            .SetQueryParameter("around", messageId.ToString())
+            .SetQueryParameter("limit", "1")
+            .Build();
+
+        // Can be null on channels that the user cannot access
+        var response = await TryGetJsonResponseAsync(url, cancellationToken);
+        if (response is null)
+            return null;
+
+        // The endpoint returns messages around the requested ID, so make sure to only return
+        // the message that exactly matches it (it may be absent if it has been deleted).
+        return response
+            .Value.EnumerateArray()
+            .Select(Message.Parse)
+            .FirstOrDefault(m => m.Id == messageId);
     }
 
     public async IAsyncEnumerable<Message> GetMessagesAsync(
@@ -701,7 +733,21 @@ public class DiscordClient(
                     );
                 }
 
-                yield return message;
+                // Some messages, for example thread starter messages, are returned by the API as content-less references.
+                // Try to resolve them to the actual message so that they appear as they do in the Discord client.
+                var actualMessage =
+                    message.Kind == MessageKind.ThreadStarterMessage
+                    && message.Reference?.ChannelId is { } referencedChannelId
+                    && message.Reference?.MessageId is { } referencedMessageId
+                        ? await TryGetMessageAsync(
+                            referencedChannelId,
+                            referencedMessageId,
+                            cancellationToken
+                        )
+                        : null;
+
+                yield return actualMessage ?? message;
+
                 currentAfter = message.Id;
             }
         }
@@ -769,7 +815,20 @@ public class DiscordClient(
                     );
                 }
 
-                yield return message;
+                // Some messages, for example thread starter messages, are returned by the API as content-less references.
+                // Try to resolve them to the actual message so that they appear as they do in the Discord client.
+                var actualMessage =
+                    message.Kind == MessageKind.ThreadStarterMessage
+                    && message.Reference?.ChannelId is { } referencedChannelId
+                    && message.Reference?.MessageId is { } referencedMessageId
+                        ? await TryGetMessageAsync(
+                            referencedChannelId,
+                            referencedMessageId,
+                            cancellationToken
+                        )
+                        : null;
+
+                yield return actualMessage ?? message;
             }
 
             currentBefore = messages.Last().Id;

DiscordChatExporter.Core/DiscordChatExporter.Core.csproj

@@ -6,7 +6,7 @@
     <PackageReference Include="Gress" />
     <PackageReference Include="JsonExtensions" />
     <PackageReference Include="Polly" />
-    <PackageReference Include="PowerKit" PrivateAssets="all" />
+    <PackageReference Include="PowerKit" />
     <PackageReference Include="RazorBlade" />
     <PackageReference Include="Superpower" />
     <PackageReference Include="WebMarkupMin.Core" />

DiscordChatExporter.Core/Exporting/ExportAssetDownloader.cs

@@ -38,23 +38,28 @@ internal partial class ExportAssetDownloader(string workingDirPath, bool reuse)
             return _previousPathsByUrl[url] = filePath;
 
         // Check for a file cached by the legacy naming scheme (5-char hash) and rename it
-        // to the new naming scheme to preserve backwards compatibility with existing exports
+        // to the new naming scheme to preserve backwards compatibility with existing exports.
+        // This will catch both the 5-char lowercase hash and the 5-char uppercase hash variants.
         if (reuse)
         {
-            var legacyFilePath = Path.Combine(workingDirPath, GetLegacyFileNameFromUrl(url));
-            if (File.Exists(legacyFilePath))
+            var legacyFileNames = GetLegacyFileNamesFromUrl(url);
+            foreach (var legacyFileName in legacyFileNames)
             {
-                // Overwrite in case the destination file was created concurrently between our
-                // earlier existence check and this move operation
-                try
+                var legacyFilePath = Path.Combine(workingDirPath, legacyFileName);
+                if (File.Exists(legacyFilePath))
                 {
-                    File.Move(legacyFilePath, filePath, overwrite: true);
-                    return _previousPathsByUrl[url] = filePath;
-                }
-                catch (IOException)
-                {
-                    // The legacy file was moved or deleted concurrently or something else happened.
-                    // Upgrading old files is not crucial, so we can just move on.
+                    // Overwrite in case the destination file was created concurrently between our
+                    // earlier existence check and this move operation
+                    try
+                    {
+                        File.Move(legacyFilePath, filePath, true);
+                        return _previousPathsByUrl[url] = filePath;
+                    }
+                    catch (IOException)
+                    {
+                        // The legacy file was moved or deleted concurrently or something else happened.
+                        // Upgrading old files is not crucial, so we can just move on.
+                    }
                 }
             }
         }
@@ -87,10 +92,16 @@ internal partial class ExportAssetDownloader
 {
     private static string NormalizeUrl(string url)
     {
-        // Remove signature parameters from Discord CDN URLs to normalize them
+        // Remove signature parameters from Discord CDN/media URLs to normalize them
         var uri = new Uri(url);
-        if (!string.Equals(uri.Host, "cdn.discordapp.com", StringComparison.OrdinalIgnoreCase))
+
+        if (
+            !string.Equals(uri.Host, "cdn.discordapp.com", StringComparison.OrdinalIgnoreCase)
+            && !string.Equals(uri.Host, "media.discordapp.net", StringComparison.OrdinalIgnoreCase)
+        )
+        {
             return url;
+        }
 
         var query = HttpUtility.ParseQueryString(uri.Query);
         query.Remove("ex");
@@ -137,13 +148,16 @@ internal partial class ExportAssetDownloader
         );
 
     // Legacy naming used a 5-char hash, kept for backwards compatibility with existing exports
-    private static string GetLegacyFileNameFromUrl(string url) =>
-        GetFileNameFromUrl(
-            url,
-            SHA256
-                .HashData(Encoding.UTF8.GetBytes(NormalizeUrl(url)))
-                .Pipe(Convert.ToHexStringLower)
-                // 5 chars = 20 bits, reaches 1% collision probability at ~145 files
-                .Truncate(5)
-        );
+    private static IReadOnlyList<string> GetLegacyFileNamesFromUrl(string url)
+    {
+        var hashData = SHA256.HashData(Encoding.UTF8.GetBytes(NormalizeUrl(url)));
+
+        return
+        [
+            // Lowercase variant (introduced in 2.46.1)
+            GetFileNameFromUrl(url, Convert.ToHexStringLower(hashData).Truncate(5)),
+            // Uppercase variant (original)
+            GetFileNameFromUrl(url, Convert.ToHexString(hashData).Truncate(5)),
+        ];
+    }
 }

DiscordChatExporter.Core/Exporting/ExportRequest.cs

@@ -206,10 +206,15 @@ public partial class ExportRequest
     {
         var actualOutputPath = FormatPath(outputPath, guild, channel, after, before);
 
-        // Output is a directory
+        // Determine whether the output path refers to a directory or a file.
+        // The extension-based heuristic is evaluated on the original, unsubstituted path,
+        // because the value of a template token (e.g. a guild or channel name) may contain
+        // a period that would otherwise be mistaken for a file extension, incorrectly causing
+        // a directory path to be treated as a file.
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/1502
         if (
             Directory.Exists(actualOutputPath)
-            || string.IsNullOrWhiteSpace(Path.GetExtension(actualOutputPath))
+            || string.IsNullOrWhiteSpace(Path.GetExtension(outputPath))
         )
         {
             var fileName = GetDefaultOutputFileName(guild, channel, format, after, before);

DiscordChatExporter.Gui/DiscordChatExporter.Gui.csproj

@@ -31,7 +31,7 @@
     <PackageReference Include="Cogwheel" />
     <PackageReference Include="CommunityToolkit.Mvvm" />
     <PackageReference Include="CSharpier.MsBuild" PrivateAssets="all" />
-    <PackageReference Include="Deorcify" PrivateAssets="all" />
+    <PackageReference Include="Deorcify" />
     <PackageReference Include="DialogHost.Avalonia" />
     <PackageReference Include="Gress" />
     <PackageReference Include="Markdig" />
@@ -39,7 +39,7 @@
     <PackageReference Include="Material.Icons.Avalonia" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" />
     <PackageReference Include="Onova" />
-    <PackageReference Include="PowerKit" PrivateAssets="all" />
+    <PackageReference Include="PowerKit" />
     <PackageReference Include="ThisAssembly.Project" PrivateAssets="all" />
   </ItemGroup>