Support logs compressed with RAR

Fixes #97

.gitignore

@@ -260,9 +260,7 @@ paket-files/
 __pycache__/
 *.pyc
 launchSettings.json
-bot.db
 .vscode/
-thumbs.db
+*.db
 *.db-journal
-
-logs/
+logs/

CompatBot/CompatBot.csproj

@@ -26,6 +26,7 @@
     <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="2.1.2" />
     <PackageReference Include="NLog" Version="4.5.10" />
     <PackageReference Include="NReco.Text.AhoCorasickDoubleArrayTrie" Version="1.0.1" />
+    <PackageReference Include="SharpCompress" Version="0.22.0" />
     <PackageReference Include="System.IO.Pipelines" Version="4.5.2" />
   </ItemGroup>
 

CompatBot/EventHandlers/LogParsing/SourceHandlers/RarHandler.cs

@@ -0,0 +1,90 @@
+using System;
+using System.Buffers;
+using System.IO;
+using System.IO.Pipelines;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Threading.Tasks;
+using CompatBot.Utils;
+using DSharpPlus.Entities;
+using SharpCompress.Archives.Rar;
+
+namespace CompatBot.EventHandlers.LogParsing.SourceHandlers
+{
+    public class RarHandler: ISourceHandler
+    {
+        private static readonly ArrayPool<byte> bufferPool = ArrayPool<byte>.Create(1024, 16);
+
+        public async Task<bool> CanHandleAsync(DiscordAttachment attachment)
+        {
+            if (!attachment.FileName.EndsWith(".rar", StringComparison.InvariantCultureIgnoreCase))
+                return false;
+
+            try
+            {
+                using (var client = HttpClientFactory.Create())
+                using (var stream = await client.GetStreamAsync(attachment.Url).ConfigureAwait(false))
+                {
+                    var buf = bufferPool.Rent(1024);
+                    var read = await stream.ReadBytesAsync(buf).ConfigureAwait(false);
+                    var firstEntry = Encoding.ASCII.GetString(new ReadOnlySpan<byte>(buf, 0, read));
+                    var result = firstEntry.Contains(".log", StringComparison.InvariantCultureIgnoreCase);
+                    bufferPool.Return(buf);
+                    return result;
+                }
+            }
+            catch (Exception e)
+            {
+                Config.Log.Error(e, "Error sniffing the rar content");
+                return false;
+            }
+        }
+
+        public async Task FillPipeAsync(DiscordAttachment attachment, PipeWriter writer)
+        {
+            try
+            {
+                using (var fileStream = new FileStream(Path.GetTempFileName(), FileMode.Create, FileAccess.ReadWrite, FileShare.Read, 16384, FileOptions.Asynchronous | FileOptions.RandomAccess | FileOptions.DeleteOnClose))
+                {
+                    using (var client = HttpClientFactory.Create())
+                    using (var downloadStream = await client.GetStreamAsync(attachment.Url).ConfigureAwait(false))
+                        await downloadStream.CopyToAsync(fileStream, 16384, Config.Cts.Token).ConfigureAwait(false);
+                    fileStream.Seek(0, SeekOrigin.Begin);
+                    using (var rarArchive = RarArchive.Open(fileStream))
+                    {
+                        using (var rarReader = rarArchive.ExtractAllEntries())
+                        {
+                            while (rarReader.MoveToNextEntry())
+                            {
+                                if (!rarReader.Entry.IsDirectory && rarReader.Entry.Key.EndsWith(".log", StringComparison.InvariantCultureIgnoreCase))
+                                {
+                                    using (var rarStream = rarReader.OpenEntryStream())
+                                    {
+                                        int read;
+                                        FlushResult flushed;
+                                        do
+                                        {
+                                            var memory = writer.GetMemory(Config.MinimumBufferSize);
+                                            read = await rarStream.ReadAsync(memory, Config.Cts.Token);
+                                            writer.Advance(read);
+                                            flushed = await writer.FlushAsync(Config.Cts.Token).ConfigureAwait(false);
+                                        } while (read > 0 && !(flushed.IsCompleted || flushed.IsCanceled || Config.Cts.IsCancellationRequested));
+                                    }
+                                    writer.Complete();
+                                    return;
+                                }
+                            }
+                        }
+                    }
+                    Config.Log.Warn("No rar entries that match the log criteria");
+                }
+            }
+            catch (Exception e)
+            {
+                Config.Log.Error(e, "Error filling the log pipe");
+            }
+            writer.Complete();
+        }
+    }
+}

CompatBot/EventHandlers/LogParsingHandler.cs

@@ -24,6 +24,7 @@ namespace CompatBot.EventHandlers
             new GzipHandler(),
             new PlainTextHandler(),
             new ZipHandler(),
+            new RarHandler(),
         };
 
         private static readonly SemaphoreSlim QueueLimiter = new SemaphoreSlim(Math.Max(1, Environment.ProcessorCount / 2), Math.Max(1, Environment.ProcessorCount / 2));
@@ -134,7 +135,6 @@ namespace CompatBot.EventHandlers
                     var potentialLogExtension = message.Attachments.Select(a => Path.GetExtension(a.FileName).ToUpperInvariant().TrimStart('.')).FirstOrDefault();
                     switch (potentialLogExtension)
                     {
-                        case "RAR":
                         case "7Z":
                         {
                             await args.Channel.SendMessageAsync($"{message.Author.Mention} {potentialLogExtension} archive type is not supported, re-upload log compressed as **ZIP**").ConfigureAwait(false);