From e8e1bbffd954dfb65767212ad55f6e312ad42ff4 Mon Sep 17 00:00:00 2001
From: Claus Vium <cvium@users.noreply.github.com>
Date: Sun, 13 Dec 2020 20:12:07 +0100
Subject: [PATCH] Merge pull request #4713 from crobibero/robots

(cherry picked from commit a3a7467f49d3aa4b4fe194696e426abe62177e38)
Signed-off-by: Joshua M. Boniface <joshua@boniface.me>
---
 .../ApiApplicationBuilderExtensions.cs        | 23 ++++++++
 .../LegacyEmbyRouteRewriteMiddleware.cs       | 54 +++++++++++++++++++
 .../Middleware/RobotsRedirectionMiddleware.cs | 47 ++++++++++++++++
 Jellyfin.Server/Startup.cs                    |  4 ++
 4 files changed, 128 insertions(+)
 create mode 100644 Jellyfin.Server/Middleware/LegacyEmbyRouteRewriteMiddleware.cs
 create mode 100644 Jellyfin.Server/Middleware/RobotsRedirectionMiddleware.cs

diff --git a/Jellyfin.Server/Extensions/ApiApplicationBuilderExtensions.cs b/Jellyfin.Server/Extensions/ApiApplicationBuilderExtensions.cs
index 6bf6f383fc..88e2b4152b 100644
--- a/Jellyfin.Server/Extensions/ApiApplicationBuilderExtensions.cs
+++ b/Jellyfin.Server/Extensions/ApiApplicationBuilderExtensions.cs
@@ -107,5 +107,28 @@ namespace Jellyfin.Server.Extensions
         {
             return appBuilder.UseMiddleware<WebSocketHandlerMiddleware>();
         }
+
+        /// <summary>
+        /// Adds robots.txt redirection to the application pipeline.
+        /// </summary>
+        /// <param name="appBuilder">The application builder.</param>
+        /// <returns>The updated application builder.</returns>
+        public static IApplicationBuilder UseRobotsRedirection(this IApplicationBuilder appBuilder)
+        {
+            return appBuilder.UseMiddleware<RobotsRedirectionMiddleware>();
+        }
+
+        /// <summary>
+        /// Adds /emby and /mediabrowser route trimming to the application pipeline.
+        /// </summary>
+        /// <remarks>
+        /// This must be injected before any path related middleware.
+        /// </remarks>
+        /// <param name="appBuilder">The application builder.</param>
+        /// <returns>The updated application builder.</returns>
+        public static IApplicationBuilder UsePathTrim(this IApplicationBuilder appBuilder)
+        {
+            return appBuilder.UseMiddleware<LegacyEmbyRouteRewriteMiddleware>();
+        }
     }
 }
diff --git a/Jellyfin.Server/Middleware/LegacyEmbyRouteRewriteMiddleware.cs b/Jellyfin.Server/Middleware/LegacyEmbyRouteRewriteMiddleware.cs
new file mode 100644
index 0000000000..fdd8974d2b
--- /dev/null
+++ b/Jellyfin.Server/Middleware/LegacyEmbyRouteRewriteMiddleware.cs
@@ -0,0 +1,54 @@
+using System;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+
+namespace Jellyfin.Server.Middleware
+{
+    /// <summary>
+    /// Removes /emby and /mediabrowser from requested route.
+    /// </summary>
+    public class LegacyEmbyRouteRewriteMiddleware
+    {
+        private const string EmbyPath = "/emby";
+        private const string MediabrowserPath = "/mediabrowser";
+
+        private readonly RequestDelegate _next;
+        private readonly ILogger<LegacyEmbyRouteRewriteMiddleware> _logger;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="LegacyEmbyRouteRewriteMiddleware"/> class.
+        /// </summary>
+        /// <param name="next">The next delegate in the pipeline.</param>
+        /// <param name="logger">The logger.</param>
+        public LegacyEmbyRouteRewriteMiddleware(
+            RequestDelegate next,
+            ILogger<LegacyEmbyRouteRewriteMiddleware> logger)
+        {
+            _next = next;
+            _logger = logger;
+        }
+
+        /// <summary>
+        /// Executes the middleware action.
+        /// </summary>
+        /// <param name="httpContext">The current HTTP context.</param>
+        /// <returns>The async task.</returns>
+        public async Task Invoke(HttpContext httpContext)
+        {
+            var localPath = httpContext.Request.Path.ToString();
+            if (localPath.StartsWith(EmbyPath, StringComparison.OrdinalIgnoreCase))
+            {
+                httpContext.Request.Path = localPath[EmbyPath.Length..];
+                _logger.LogDebug("Removing {EmbyPath} from route.", EmbyPath);
+            }
+            else if (localPath.StartsWith(MediabrowserPath, StringComparison.OrdinalIgnoreCase))
+            {
+                httpContext.Request.Path = localPath[MediabrowserPath.Length..];
+                _logger.LogDebug("Removing {MediabrowserPath} from route.", MediabrowserPath);
+            }
+
+            await _next(httpContext).ConfigureAwait(false);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Jellyfin.Server/Middleware/RobotsRedirectionMiddleware.cs b/Jellyfin.Server/Middleware/RobotsRedirectionMiddleware.cs
new file mode 100644
index 0000000000..9d40d74fe9
--- /dev/null
+++ b/Jellyfin.Server/Middleware/RobotsRedirectionMiddleware.cs
@@ -0,0 +1,47 @@
+using System;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+
+namespace Jellyfin.Server.Middleware
+{
+    /// <summary>
+    /// Redirect requests to robots.txt to web/robots.txt.
+    /// </summary>
+    public class RobotsRedirectionMiddleware
+    {
+        private readonly RequestDelegate _next;
+        private readonly ILogger<RobotsRedirectionMiddleware> _logger;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="RobotsRedirectionMiddleware"/> class.
+        /// </summary>
+        /// <param name="next">The next delegate in the pipeline.</param>
+        /// <param name="logger">The logger.</param>
+        public RobotsRedirectionMiddleware(
+            RequestDelegate next,
+            ILogger<RobotsRedirectionMiddleware> logger)
+        {
+            _next = next;
+            _logger = logger;
+        }
+
+        /// <summary>
+        /// Executes the middleware action.
+        /// </summary>
+        /// <param name="httpContext">The current HTTP context.</param>
+        /// <returns>The async task.</returns>
+        public async Task Invoke(HttpContext httpContext)
+        {
+            var localPath = httpContext.Request.Path.ToString();
+            if (string.Equals(localPath, "/robots.txt", StringComparison.OrdinalIgnoreCase))
+            {
+                _logger.LogDebug("Redirecting robots.txt request to web/robots.txt");
+                httpContext.Response.Redirect("web/robots.txt");
+                return;
+            }
+
+            await _next(httpContext).ConfigureAwait(false);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Jellyfin.Server/Startup.cs b/Jellyfin.Server/Startup.cs
index aa3ef53500..3395d2413f 100644
--- a/Jellyfin.Server/Startup.cs
+++ b/Jellyfin.Server/Startup.cs
@@ -128,6 +128,8 @@ namespace Jellyfin.Server
                     mainApp.UseHttpsRedirection();
                 }
 
+                // This must be injected before any path related middleware.
+                mainApp.UsePathTrim();
                 mainApp.UseStaticFiles();
                 if (appConfig.HostWebClient())
                 {
@@ -142,6 +144,8 @@ namespace Jellyfin.Server
                         RequestPath = "/web",
                         ContentTypeProvider = extensionProvider
                     });
+
+                    mainApp.UseRobotsRedirection();
                 }
 
                 mainApp.UseAuthentication();