1 files changed, 84 insertions, 0 deletions
diff --git a/Jellyfin.Server/Middleware/BaseUrlRedirectionMiddleware.cs b/Jellyfin.Server/Middleware/BaseUrlRedirectionMiddleware.cs
new file mode 100644
index 000000000..3e5982eed
--- /dev/null
+++ b/Jellyfin.Server/Middleware/BaseUrlRedirectionMiddleware.cs
@@ -0,0 +1,84 @@
+using System;
+using System.Threading.Tasks;
+using Jellyfin.Networking.Configuration;
+using MediaBrowser.Controller.Configuration;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+using ConfigurationExtensions = MediaBrowser.Controller.Extensions.ConfigurationExtensions;
+
+namespace Jellyfin.Server.Middleware
+{
+    /// <summary>
+    /// Redirect requests without baseurl prefix to the baseurl prefixed URL.
+    /// </summary>
+    public class BaseUrlRedirectionMiddleware
+    {
+        private readonly RequestDelegate _next;
+        private readonly ILogger<BaseUrlRedirectionMiddleware> _logger;
+        private readonly IConfiguration _configuration;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="BaseUrlRedirectionMiddleware"/> class.
+        /// </summary>
+        /// <param name="next">The next delegate in the pipeline.</param>
+        /// <param name="logger">The logger.</param>
+        /// <param name="configuration">The application configuration.</param>
+        public BaseUrlRedirectionMiddleware(
+            RequestDelegate next,
+            ILogger<BaseUrlRedirectionMiddleware> logger,
+            IConfiguration configuration)
+        {
+            _next = next;
+            _logger = logger;
+            _configuration = configuration;
+        }
+
+        /// <summary>
+        /// Executes the middleware action.
+        /// </summary>
+        /// <param name="httpContext">The current HTTP context.</param>
+        /// <param name="serverConfigurationManager">The server configuration manager.</param>
+        /// <returns>The async task.</returns>
+        public async Task Invoke(HttpContext httpContext, IServerConfigurationManager serverConfigurationManager)
+        {
+            var localPath = httpContext.Request.Path.ToString();
+            var baseUrlPrefix = serverConfigurationManager.GetNetworkConfiguration().BaseUrl;
+
+            if (!string.IsNullOrEmpty(baseUrlPrefix))
+            {
+                var startsWithBaseUrl = localPath.StartsWith(baseUrlPrefix, StringComparison.OrdinalIgnoreCase);
+
+                if (!startsWithBaseUrl
+                    && (localPath.Equals("/health", StringComparison.OrdinalIgnoreCase)
+                        || localPath.Equals("/health/", StringComparison.OrdinalIgnoreCase)))
+                {
+                    _logger.LogDebug("Redirecting /health check");
+                    httpContext.Response.Redirect(baseUrlPrefix + "/health");
+                    return;
+                }
+
+                if (!startsWithBaseUrl
+                    || localPath.Length == baseUrlPrefix.Length
+                    // Local path is /baseUrl/
+                    || (localPath.Length == baseUrlPrefix.Length + 1 && localPath[^1] == '/'))
+                {
+                    // Always redirect back to the default path if the base prefix is invalid, missing, or is the full path.
+                    _logger.LogDebug("Normalizing an URL at {LocalPath}", localPath);
+                    httpContext.Response.Redirect(baseUrlPrefix + "/" + _configuration[ConfigurationExtensions.DefaultRedirectKey]);
+                    return;
+                }
+            }
+            else if (string.IsNullOrEmpty(localPath)
+                     || localPath.Equals("/", StringComparison.Ordinal))
+            {
+                // Always redirect back to the default path if root is requested.
+                _logger.LogDebug("Normalizing an URL at {LocalPath}", localPath);
+                httpContext.Response.Redirect("/" + _configuration[ConfigurationExtensions.DefaultRedirectKey]);
+                return;
+            }
+
+            await _next(httpContext).ConfigureAwait(false);
+        }
+    }
+}