Handle offline login gracefully instead of a raw MSAL error

backend/FwLite/FwLiteShared.Tests/Auth/OAuthClientFailureClassifierTests.cs

@@ -44,4 +44,36 @@ public void AnyOtherFailure_KeepsCachedCredentials(Exception e)
 
         outcome.Should().Be(OAuthClient.SilentAuthFailureOutcome.KeepCachedCredentials);
     }
+
+    [Fact]
+    public void OidcFetchFailure_IsOffline()
+    {
+        //the real-world offline error: MSAL fails to fetch the OIDC config, wrapping the connection failure
+        var e = new MsalServiceException("oidc_failure", "Failed to retrieve OIDC configuration",
+            new HttpRequestException("Connection failure"));
+
+        var result = OAuthClient.ClassifyInteractiveLoginFailure(e);
+
+        result.Should().Be(LoginResult.Offline);
+    }
+
+    [Fact]
+    public void UserCancel_IsCancelled()
+    {
+        //a cancel is a cancel regardless of connectivity; offline-with-warm-cache also lands here
+        var e = new MsalClientException(MsalError.AuthenticationCanceledError, "User canceled authentication");
+
+        var result = OAuthClient.ClassifyInteractiveLoginFailure(e);
+
+        result.Should().Be(LoginResult.Cancelled);
+    }
+
+    [Fact]
+    public void UnexpectedFailure_IsNotClassified_SoCallerRethrows()
+    {
+        var result = OAuthClient.ClassifyInteractiveLoginFailure(
+            new InvalidOperationException("something unexpected"));
+
+        result.Should().BeNull();
+    }
 }

backend/FwLite/FwLiteShared/Auth/AuthService.cs

@@ -1,11 +1,26 @@
+using System.Text.Json.Serialization;
 using FwLiteShared.Projects;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using Microsoft.JSInterop;
 
 namespace FwLiteShared.Auth;
 
 public record ServerStatus(string DisplayName, bool LoggedIn, string? LoggedInAs, LexboxServer Server);
-public class AuthService(LexboxProjectService lexboxProjectService, OAuthClientFactory clientFactory, IOptions<AuthConfig> options)
+
+[JsonConverter(typeof(JsonStringEnumConverter))]
+public enum LoginResult
+{
+    Success,
+    Offline,
+    Cancelled,
+}
+
+public class AuthService(
+    LexboxProjectService lexboxProjectService,
+    OAuthClientFactory clientFactory,
+    ILogger<AuthService> logger,
+    IOptions<AuthConfig> options)
 {
     [JSInvokable]
     public async Task<ServerStatus[]> Servers()
@@ -21,11 +36,22 @@ public async Task<ServerStatus[]> Servers()
     }
 
     [JSInvokable]
-    public async Task SignInWebView(LexboxServer server)
+    public async Task<LoginResult> SignInWebView(LexboxServer server)
     {
-        var result = await clientFactory.GetClient(server).SignIn(string.Empty);//does nothing here
-        if (!result.HandledBySystemWebView) throw new InvalidOperationException("Sign in not handled by system web view");
-        options.Value.AfterLoginWebView?.Invoke();
+        try
+        {
+            var result = await clientFactory.GetClient(server).SignIn(string.Empty);//does nothing here
+            if (!result.HandledBySystemWebView) throw new InvalidOperationException("Sign in not handled by system web view");
+            options.Value.AfterLoginWebView?.Invoke();
+            return LoginResult.Success;
+        }
+        catch (Exception e)
+        {
+            var classified = OAuthClient.ClassifyInteractiveLoginFailure(e);
+            if (classified is null) throw;
+            logger.LogInformation(e, "Web view sign in did not complete: {LoginResult}", classified);
+            return classified.Value;
+        }
     }
 
     [JSInvokable]

backend/FwLite/FwLiteShared/Auth/OAuthClient.cs

@@ -300,6 +300,14 @@ internal enum SilentAuthFailureOutcome
         _ => SilentAuthFailureOutcome.KeepCachedCredentials,
     };
 
+    internal static LoginResult? ClassifyInteractiveLoginFailure(Exception e) => e switch
+    {
+        MsalServiceException { InnerException: HttpRequestException } => LoginResult.Offline,
+        HttpRequestException or OperationCanceledException => LoginResult.Offline,
+        MsalClientException { ErrorCode: MsalError.AuthenticationCanceledError } => LoginResult.Cancelled,
+        _ => null,
+    };
+
     public async Task<string?> GetCurrentName()
     {
         var auth = await GetAuth();

backend/FwLite/FwLiteShared/TypeGen/ReinforcedFwLiteTypingConfig.cs

@@ -148,6 +148,7 @@ private static void ConfigureFwLiteSharedTypes(ConfigurationBuilder builder)
         builder.ExportAsEnum<ProjectRole>().UseString();
         builder.ExportAsEnum<MorphTypeKind>().UseString();
         builder.ExportAsEnum<SyncStatus>().UseString();
+        builder.ExportAsEnum<LoginResult>().UseString();
         builder.ExportAsEnum<DownloadProjectByCodeResult>().UseString();
         builder.ExportAsEnum<SyncJobStatusEnum>().UseString();
         builder.ExportAsEnum<ViewBase>().UseString();

frontend/viewer/src/lib/auth/LoginButton.svelte

@@ -16,8 +16,11 @@
 <script lang="ts">
   import * as ResponsiveMenu from '$lib/components/responsive-menu';
   import type {ILexboxServer} from '$lib/dotnet-types';
+  import {LoginResult} from '$lib/dotnet-types';
   import {useAuthService} from '$lib/services/service-provider';
   import {Button} from '$lib/components/ui/button';
+  import {AppNotification} from '$lib/notifications/notifications';
+  import {openUrl} from '$lib/services/url-opener';
 
   const authService = useAuthService();
   const shouldUseSystemWebView = useSystemWebView(authService);
@@ -40,8 +43,25 @@
   async function login(server: ILexboxServer) {
     loading = true;
     try {
-      await authService.signInWebView(server);
-      statusChange('logged-in');
+      const result = await authService.signInWebView(server);
+
+      if (result === LoginResult.Success) {
+        statusChange('logged-in');
+      } else if (result === LoginResult.Offline) {
+        AppNotification.displayAction(
+          $t`You appear to be offline. Can you connect to ${server.displayName}?`,
+          {
+            label: $t`Open in browser`,
+            callback: () => {
+              void openUrl(server.authority);
+              return {dismiss: true};
+            },
+          },
+          {type: 'warning'},
+        );
+      } else {
+        AppNotification.display($t`Login cancelled.`, {type: 'warning', timeout: 'short'});
+      }
     } finally {
       loading = false;
     }
@@ -56,6 +76,7 @@
       loading = false;
     }
   }
+
 </script>
 
 {#if status.loggedIn}

frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Auth/IAuthService.ts

@@ -4,12 +4,13 @@
 //     the code is regenerated.
 
 import type {IServerStatus} from './IServerStatus';
+import type {LoginResult} from './LoginResult';
 import type {ILexboxServer} from './ILexboxServer';
 
 export interface IAuthService
 {
 	servers() : Promise<IServerStatus[]>;
-	signInWebView(server: ILexboxServer) : Promise<void>;
+	signInWebView(server: ILexboxServer) : Promise<LoginResult>;
 	useSystemWebView() : Promise<boolean>;
 	logout(server: ILexboxServer) : Promise<void>;
 }

frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Auth/LoginResult.ts

@@ -0,0 +1,11 @@
+/* eslint-disable */
+//     This code was generated by a Reinforced.Typings tool.
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+
+export enum LoginResult {
+	Success = "Success",
+	Offline = "Offline",
+	Cancelled = "Cancelled"
+}
+/* eslint-enable */

frontend/viewer/src/lib/dotnet-types/index.ts

@@ -1,6 +1,7 @@
 export * from './generated-types/FwLiteShared/Auth/IAuthService';
 export * from './generated-types/FwLiteShared/Auth/ILexboxServer';
 export * from './generated-types/FwLiteShared/Auth/IServerStatus';
+export * from './generated-types/FwLiteShared/Auth/LoginResult';
 export * from './generated-types/FwLiteShared/Projects/ICombinedProjectsService';
 export * from './generated-types/FwLiteShared/Projects/IProjectModel';
 export * from './generated-types/FwLiteShared/Projects/IServerProjects';

frontend/viewer/src/locales/en.po

@@ -1122,6 +1122,11 @@ msgstr "Local only"
 msgid "Login"
 msgstr "Login"
 
+#. Toast shown when the user closes or cancels the login dialog before signing in.
+#: src/lib/auth/LoginButton.svelte
+msgid "Login cancelled."
+msgstr "Login cancelled."
+
 #. Default button label on the login button when not yet authenticated. Clicking opens the login flow for a server.
 #: src/lib/auth/LoginButton.svelte
 #: src/lib/auth/LoginButton.svelte
@@ -1409,6 +1414,11 @@ msgstr "Open"
 msgid "Open Data Directory"
 msgstr "Open Data Directory"
 
+#. Action button on the offline-login warning toast; opens the server's site in a browser so the user can check the connection.
+#: src/lib/auth/LoginButton.svelte
+msgid "Open in browser"
+msgstr "Open in browser"
+
 #. Button label
 #: src/lib/components/OpenInFieldWorksButton.svelte
 msgid "Open in FieldWorks"
@@ -2166,6 +2176,11 @@ msgstr "Writing systems"
 msgid "Writing Systems"
 msgstr "Writing Systems"
 
+#. Warning toast shown when a login attempt can't connect to the server. {0} is the server name (e.g. "Lexbox").
+#: src/lib/auth/LoginButton.svelte
+msgid "You appear to be offline. Can you connect to {0}?"
+msgstr "You appear to be offline. Can you connect to {0}?"
+
 #. Status message when no updates are available
 #: src/lib/updates/UpdateDialogContent.svelte
 msgid "You are running the latest version."

frontend/viewer/src/locales/es.po

@@ -1127,6 +1127,11 @@ msgstr "Sólo local"
 msgid "Login"
 msgstr "Inicio de sesión"
 
+#. Toast shown when the user closes or cancels the login dialog before signing in.
+#: src/lib/auth/LoginButton.svelte
+msgid "Login cancelled."
+msgstr ""
+
 #. Default button label on the login button when not yet authenticated. Clicking opens the login flow for a server.
 #: src/lib/auth/LoginButton.svelte
 #: src/lib/auth/LoginButton.svelte
@@ -1414,6 +1419,11 @@ msgstr "Abrir"
 msgid "Open Data Directory"
 msgstr "Directorio de datos abiertos"
 
+#. Action button on the offline-login warning toast; opens the server's site in a browser so the user can check the connection.
+#: src/lib/auth/LoginButton.svelte
+msgid "Open in browser"
+msgstr ""
+
 #. Button label
 #: src/lib/components/OpenInFieldWorksButton.svelte
 msgid "Open in FieldWorks"
@@ -2171,6 +2181,10 @@ msgstr "Sistemas de escritura"
 msgid "Writing Systems"
 msgstr "Sistemas de escritura"
 
+#: src/lib/auth/LoginButton.svelte
+msgid "You appear to be offline. Can you connect to {0}?"
+msgstr ""
+
 #. Status message when no updates are available
 #: src/lib/updates/UpdateDialogContent.svelte
 msgid "You are running the latest version."

frontend/viewer/src/locales/fr.po

@@ -1127,6 +1127,11 @@ msgstr "Uniquement au niveau local"
 msgid "Login"
 msgstr "Connexion"
 
+#. Toast shown when the user closes or cancels the login dialog before signing in.
+#: src/lib/auth/LoginButton.svelte
+msgid "Login cancelled."
+msgstr ""
+
 #. Default button label on the login button when not yet authenticated. Clicking opens the login flow for a server.
 #: src/lib/auth/LoginButton.svelte
 #: src/lib/auth/LoginButton.svelte
@@ -1414,6 +1419,11 @@ msgstr "Ouvert"
 msgid "Open Data Directory"
 msgstr "Répertoire des données ouvertes"
 
+#. Action button on the offline-login warning toast; opens the server's site in a browser so the user can check the connection.
+#: src/lib/auth/LoginButton.svelte
+msgid "Open in browser"
+msgstr ""
+
 #. Button label
 #: src/lib/components/OpenInFieldWorksButton.svelte
 msgid "Open in FieldWorks"
@@ -2171,6 +2181,10 @@ msgstr "Systèmes d'écriture"
 msgid "Writing Systems"
 msgstr "Systèmes d'écriture"
 
+#: src/lib/auth/LoginButton.svelte
+msgid "You appear to be offline. Can you connect to {0}?"
+msgstr ""
+
 #. Status message when no updates are available
 #: src/lib/updates/UpdateDialogContent.svelte
 msgid "You are running the latest version."

frontend/viewer/src/locales/id.po

@@ -1127,6 +1127,11 @@ msgstr "Hanya lokal"
 msgid "Login"
 msgstr "Masuk"
 
+#. Toast shown when the user closes or cancels the login dialog before signing in.
+#: src/lib/auth/LoginButton.svelte
+msgid "Login cancelled."
+msgstr ""
+
 #. Default button label on the login button when not yet authenticated. Clicking opens the login flow for a server.
 #: src/lib/auth/LoginButton.svelte
 #: src/lib/auth/LoginButton.svelte
@@ -1414,6 +1419,11 @@ msgstr "Buka"
 msgid "Open Data Directory"
 msgstr "Direktori Data Terbuka"
 
+#. Action button on the offline-login warning toast; opens the server's site in a browser so the user can check the connection.
+#: src/lib/auth/LoginButton.svelte
+msgid "Open in browser"
+msgstr ""
+
 #. Button label
 #: src/lib/components/OpenInFieldWorksButton.svelte
 msgid "Open in FieldWorks"
@@ -2171,6 +2181,10 @@ msgstr "Sistem penulisan"
 msgid "Writing Systems"
 msgstr "Sistem Penulisan"
 
+#: src/lib/auth/LoginButton.svelte
+msgid "You appear to be offline. Can you connect to {0}?"
+msgstr ""
+
 #. Status message when no updates are available
 #: src/lib/updates/UpdateDialogContent.svelte
 msgid "You are running the latest version."

frontend/viewer/src/locales/ko.po

@@ -1127,6 +1127,11 @@ msgstr "로컬 전용"
 msgid "Login"
 msgstr "로그인"
 
+#. Toast shown when the user closes or cancels the login dialog before signing in.
+#: src/lib/auth/LoginButton.svelte
+msgid "Login cancelled."
+msgstr ""
+
 #. Default button label on the login button when not yet authenticated. Clicking opens the login flow for a server.
 #: src/lib/auth/LoginButton.svelte
 #: src/lib/auth/LoginButton.svelte
@@ -1414,6 +1419,11 @@ msgstr "열기"
 msgid "Open Data Directory"
 msgstr "오픈 데이터 디렉터리"
 
+#. Action button on the offline-login warning toast; opens the server's site in a browser so the user can check the connection.
+#: src/lib/auth/LoginButton.svelte
+msgid "Open in browser"
+msgstr ""
+
 #. Button label
 #: src/lib/components/OpenInFieldWorksButton.svelte
 msgid "Open in FieldWorks"
@@ -2171,6 +2181,10 @@ msgstr "쓰기 시스템"
 msgid "Writing Systems"
 msgstr "쓰기 시스템"
 
+#: src/lib/auth/LoginButton.svelte
+msgid "You appear to be offline. Can you connect to {0}?"
+msgstr ""
+
 #. Status message when no updates are available
 #: src/lib/updates/UpdateDialogContent.svelte
 msgid "You are running the latest version."