Fixed: Better check for write access in Calibre

src/NzbDrone.Core/Books/Calibre/CalibreProxy.cs

@@ -537,15 +537,19 @@ namespace NzbDrone.Core.Books.Calibre
             return response.Resource;
         }
 
-        private bool CalibreLoginEnabled(CalibreSettings settings)
+        private bool HasWriteAccess(CalibreSettings settings)
         {
-            var builder = GetBuilder($"/book-get-last-read-position/{settings.Library}/1", settings);
+            var request = GetBuilder($"cdb/cmd/saved_searches", settings)
-            builder.SuppressHttpError = true;
+                .Post()
+                .SetHeader("Content-Type", "application/json")
+                .Build();
+
+            request.SuppressHttpError = true;
+            request.SetContent("[\"list\"]");
 
-            var request = builder.Build();
             var response = _httpClient.Get(request);
 
-            return response.StatusCode != HttpStatusCode.NotFound;
+            return response.StatusCode != HttpStatusCode.Forbidden;
         }
 
         private HttpRequestBuilder GetBuilder(string relativePath, CalibreSettings settings)
@@ -604,16 +608,6 @@ namespace NzbDrone.Core.Books.Calibre
 
         private ValidationFailure TestCalibre(CalibreSettings settings)
         {
-            var authRequired = settings.Host != "127.0.0.1" && settings.Host != "::1" && settings.Host != "localhost";
-
-            if (authRequired && settings.Username.IsNullOrWhiteSpace())
-            {
-                return new NzbDroneValidationFailure("Username", "Username required")
-                {
-                    DetailedDescription = "A username/password is required for non-local Calibre servers to allow write access"
-                };
-            }
-
             var builder = GetBuilder("", settings);
             builder.Accept(HttpAccept.Html);
             builder.SuppressHttpError = true;
@@ -661,38 +655,18 @@ namespace NzbDrone.Core.Books.Calibre
                 return new ValidationFailure("Port", "Not a valid Calibre content server.  See https://manual.calibre-ebook.com/server.html");
             }
 
-            CalibreLibraryInfo libraryInfo;
+            if (!HasWriteAccess(settings))
-            try
             {
-                libraryInfo = GetLibraryInfo(settings);
+                return new ValidationFailure("Username", "Readarr needs write access. Configure a user or trusted IP in calibre. See See https://manual.calibre-ebook.com/server.html");
-            }
-            catch (HttpException e)
-            {
-                if (e.Response.StatusCode == HttpStatusCode.Unauthorized)
-                {
-                    return new NzbDroneValidationFailure("Username", "Authentication failure")
-                    {
-                        DetailedDescription = "Please verify your username and password."
-                    };
-                }
-                else
-                {
-                    return new NzbDroneValidationFailure(string.Empty, "Unknown exception: " + e.Message);
-                }
             }
 
+            var libraryInfo = GetLibraryInfo(settings);
+
             if (settings.Library.IsNullOrWhiteSpace())
             {
                 settings.Library = libraryInfo.DefaultLibrary;
             }
 
-            // now that we have library info, double check if auth is actually enabled calibre side.  If not, we'll get a 404 back.
-            // https://github.com/kovidgoyal/calibre/blob/bf53bbf07a6ced728bf6a87d097fb6eb8c67e4e0/src/calibre/srv/books.py#L196
-            if (authRequired && !CalibreLoginEnabled(settings))
-            {
-                return new ValidationFailure("Host", "Remote calibre server must have authentication enabled to allow Readarr write access");
-            }
-
             if (!libraryInfo.LibraryMap.ContainsKey(settings.Library))
             {
                 return new ValidationFailure("Library", "Not a valid library in calibre");