Replace on-disk index.html patching with IStartupFilter request-time injection

JellyfinPlugin/HtmlPatcher.cs

@@ -1,92 +0,0 @@
-using System;
-using System.IO;
-using System.Threading.Tasks;
-using MediaBrowser.Common.Configuration;
-using MediaBrowser.Controller.Plugins;
-using Microsoft.Extensions.Logging;
-
-using Microsoft.Extensions.Hosting;
-
-namespace JellyfinPlugin
-{
-    public class HtmlPatcher : IHostedService
-    {
-        private readonly IApplicationPaths _appPaths;
-        private readonly ILogger<HtmlPatcher> _logger;
-
-        public HtmlPatcher(IApplicationPaths appPaths, ILogger<HtmlPatcher> logger)
-        {
-            _appPaths = appPaths;
-            _logger = logger;
-        }
-
-        public Task StartAsync(CancellationToken cancellationToken)
-        {
-            PatchHtml();
-            return Task.CompletedTask;
-        }
-
-        public Task StopAsync(CancellationToken cancellationToken)
-        {
-            return Task.CompletedTask;
-        }
-
-        private void PatchHtml()
-        {
-            try
-            {
-                // Znajdujemy ścieżkę do web UI Jellyfina.
-                // W większości instalacji linuksowych (np. Debian/Ubuntu) to:
-                string[] possiblePaths = {
-                    Path.Combine(_appPaths.ProgramDataPath, "web"),
-                    "/usr/share/jellyfin/web",
-                    "/jellyfin/jellyfin-web", // Docker
-                };
-
-                string webPath = string.Empty;
-                foreach (var path in possiblePaths)
-                {
-                    if (Directory.Exists(path) && File.Exists(Path.Combine(path, "index.html")))
-                    {
-                        webPath = path;
-                        break;
-                    }
-                }
-
-                if (string.IsNullOrEmpty(webPath))
-                {
-                    _logger.LogWarning("Failed to find Jellyfin Web directory. Manual installation of the client script is required.");
-                    return;
-                }
-
-                string indexPath = Path.Combine(webPath, "index.html");
-                string indexContent = File.ReadAllText(indexPath);
-
-                string scriptTag = "<script src=\"/BlackBarRemover/ClientScript.js\"></script>";
-
-                if (!indexContent.Contains("BlackBarRemover/ClientScript.js"))
-                {
-                    indexContent = indexContent.Replace("</body>", $"    {scriptTag}\n</body>");
-                    File.WriteAllText(indexPath, indexContent);
-                    _logger.LogInformation("Successfully injected BlackBarRemover script into index.html at {Path}", indexPath);
-                }
-                else
-                {
-                    _logger.LogInformation("BlackBarRemover client script is already injected into index.html");
-                }
-            }
-            catch (UnauthorizedAccessException)
-            {
-                _logger.LogWarning("Permission denied to modify index.html. Change Jellyfin Web file permissions or add the script manually in Custom CSS.");
-            }
-            catch (Exception ex)
-            {
-                _logger.LogError(ex, "An error occurred while injecting the script into index.html.");
-            }
-        }
-
-        public void Dispose()
-        {
-        }
-    }
-}

JellyfinPlugin/PluginServiceRegistrator.cs

@@ -9,7 +9,7 @@ namespace JellyfinPlugin
         public void RegisterServices(IServiceCollection serviceCollection, MediaBrowser.Controller.IServerApplicationHost applicationHost)
         {
             // Rejestracja serwisów tła
-            serviceCollection.AddHostedService<HtmlPatcher>();
+            serviceCollection.AddSingleton<Microsoft.AspNetCore.Hosting.IStartupFilter, ScriptInjectionStartupFilter>();
             serviceCollection.AddHostedService<WrapperGenerator>();
             serviceCollection.AddHostedService<LibraryMonitor>();
 

JellyfinPlugin/ScriptInjectionStartupFilter.cs

@@ -0,0 +1,125 @@
+using System;
+using System.IO;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+
+namespace JellyfinPlugin
+{
+    public class ScriptInjectionStartupFilter : IStartupFilter
+    {
+        private readonly ILogger<ScriptInjectionStartupFilter> _logger;
+        private int _loggedOnce;
+
+        public ScriptInjectionStartupFilter(ILogger<ScriptInjectionStartupFilter> logger)
+        {
+            _logger = logger;
+        }
+
+        public Action<IApplicationBuilder> Configure(Action<IApplicationBuilder> next)
+        {
+            return app =>
+            {
+                app.Use(InvokeAsync);
+                next(app);
+            };
+        }
+
+        private async Task InvokeAsync(HttpContext context, Func<Task> nextMw)
+        {
+            if (!IsIndexRequest(context.Request.Path.Value))
+            {
+                await nextMw().ConfigureAwait(false);
+                return;
+            }
+
+            if (!HttpMethods.IsGet(context.Request.Method))
+            {
+                await nextMw().ConfigureAwait(false);
+                return;
+            }
+
+            var config = Plugin.Instance?.Configuration;
+            if (config == null || !config.IsEnabled)
+            {
+                await nextMw().ConfigureAwait(false);
+                return;
+            }
+
+            context.Request.Headers.Remove("Accept-Encoding");
+            context.Request.Headers.Remove("Range");
+            context.Request.Headers.Remove("If-Range");
+
+            var originalBody = context.Response.Body;
+            using var buffer = new MemoryStream();
+            context.Response.Body = buffer;
+            try
+            {
+                await nextMw().ConfigureAwait(false);
+            }
+            catch
+            {
+                context.Response.Body = originalBody;
+                throw;
+            }
+
+            context.Response.Body = originalBody;
+            buffer.Seek(0, SeekOrigin.Begin);
+
+            var isHtml = context.Response.StatusCode == 200
+                && (context.Response.ContentType?.Contains("text/html", StringComparison.OrdinalIgnoreCase) ?? false);
+
+            if (!isHtml)
+            {
+                await buffer.CopyToAsync(originalBody).ConfigureAwait(false);
+                return;
+            }
+
+            string html;
+            using (var reader = new StreamReader(buffer, Encoding.UTF8, true, 1024, leaveOpen: true))
+            {
+                html = await reader.ReadToEndAsync().ConfigureAwait(false);
+            }
+
+            try
+            {
+                var alreadyInjected = html.IndexOf("BlackBarRemover/ClientScript.js", StringComparison.OrdinalIgnoreCase) >= 0;
+                var bodyClose = html.LastIndexOf("</body>", StringComparison.OrdinalIgnoreCase);
+
+                if (!alreadyInjected && bodyClose >= 0)
+                {
+                    var tag = "<script src=\"/BlackBarRemover/ClientScript.js\"></script>";
+                    html = html.Substring(0, bodyClose) + tag + "\n" + html.Substring(bodyClose);
+
+                    if (System.Threading.Interlocked.Exchange(ref _loggedOnce, 1) == 0)
+                    {
+                        _logger.LogInformation("Black Bar Remover: injected the client script via request-time middleware (IStartupFilter).");
+                    }
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning($"Script injection middleware error (serving original HTML): {ex.Message}");
+            }
+
+            var bytes = Encoding.UTF8.GetBytes(html);
+            context.Response.ContentType = "text/html;charset=utf-8";
+            context.Response.ContentLength = bytes.Length;
+            context.Response.Headers.Remove("ETag");
+            context.Response.Headers.Remove("Last-Modified");
+            context.Response.Headers.Remove("Accept-Ranges");
+            await originalBody.WriteAsync(bytes, 0, bytes.Length).ConfigureAwait(false);
+        }
+
+        private static bool IsIndexRequest(string? path)
+        {
+            if (string.IsNullOrEmpty(path)) return false;
+            return path.EndsWith("/web/index.html", StringComparison.OrdinalIgnoreCase)
+                || path.EndsWith("/web/", StringComparison.OrdinalIgnoreCase)
+                || path.Equals("/web", StringComparison.OrdinalIgnoreCase);
+        }
+    }
+}