Better error handling

Author: Zverik

android/app/build.gradle

@@ -8,7 +8,7 @@ plugins {
 android {
     namespace = "info.zverev.ilya.sonamobi"
     compileSdk = flutter.compileSdkVersion
-    ndkVersion = flutter.ndkVersion
+    ndkVersion = '27.0.12077973'
 
     compileOptions {
         sourceCompatibility = JavaVersion.VERSION_21

lib/empty.dart

@@ -17,6 +17,7 @@ class EmptyWordView extends ConsumerWidget {
     final history = ref.watch(historyProvider);
     final isDark = ref.read(nightModeProvider.notifier).isDark(context);
     return Column(
+      crossAxisAlignment: CrossAxisAlignment.stretch,
       children: [
         SizedBox(height: 10.0),
         ListTile(
@@ -39,11 +40,28 @@ class EmptyWordView extends ConsumerWidget {
         ),
         SwitchListTile(
           value: ref.watch(linksProvider),
-          title: Text('Keeleõppijale'),
+          title: Text('Keeleõppija sõnavara'),
           onChanged: (value) {
             ref.read(linksProvider.notifier).toggle();
           },
         ),
+        if (history.history.length > 3)
+          GestureDetector(
+            child: Container(
+              padding: EdgeInsets.symmetric(horizontal: 16.0, vertical: 5.0),
+              color: isDark ? Colors.blue.shade900 : Colors.blue.shade100,
+              child: Text(
+                'Ava sõnaveebi veebileht',
+                style: TextStyle(
+                  color: isDark ? Colors.blue.shade100 : Colors.blue.shade900,
+                  fontSize: 18,
+                ),
+              ),
+            ),
+            onTap: () {
+              launchUrl(Uri.https('sonaveeb.ee'));
+            },
+          ),
         if (history.history.length <= 3)
           Padding(
             padding: const EdgeInsets.all(16.0),

lib/forms.dart

@@ -55,6 +55,8 @@ class _WordFormsPageState extends ConsumerState<WordFormsPage> {
       }
     } on FetchError catch (e) {
       _logger.severe('Failed to load word forms', e);
+      _webController.loadHtmlString('Failed to load word forms',
+          baseUrl: kBaseUrl);
     }
   }
 

lib/panel.dart

@@ -70,16 +70,17 @@ class _WordPageState extends ConsumerState<WordPage>
 
     _lookingFor = value;
     Map<String, dynamic> data;
+    final pages = ref.read(pageProvider);
+    final path = ref.read(linksProvider.notifier).autocomplete(value);
     try {
-      final body = await ref
-          .read(pageProvider)
-          .fetchPage(ref.read(linksProvider.notifier).autocomplete(value));
+      final body = await pages.fetchPage(path);
       data = json.decode(body);
     } on FetchError catch (e) {
       _logger.severe('Fetch error', e);
       return;
     } on FormatException catch (e) {
       _logger.severe('Json decoding error', e);
+      pages.forgetPage(path);
       return;
     }
     if (_lookingFor != value) return;

lib/providers/fetcher.dart

@@ -12,17 +12,18 @@ final pageProvider = Provider((ref) => PageProvider(ref));
 
 class FetchError implements Exception {
   final String message;
+  final String path;
   final int code;
   final String body;
   final String? url;
 
-  FetchError(this.message, http.Response? response)
+  FetchError(this.message, this.path, [http.Response? response])
       : code = response?.statusCode ?? 0,
         body = response?.body ?? '',
         url = response?.request?.url.toString();
 
   @override
-  String toString() => '$message: $code $body';
+  String toString() => '$message for $path: $code $body';
 }
 
 class PageProvider {
@@ -40,7 +41,7 @@ class PageProvider {
     final url = Uri.https(kBaseUrl);
     final response = await http.get(url);
     if (response.statusCode != 200) {
-      throw FetchError('Failed to get a cookie', response);
+      throw FetchError('Failed to get a cookie', '/', response);
     }
     final data =
         response.headers['set-cookie'] ?? response.headers['Set-Cookie'];
@@ -68,6 +69,15 @@ class PageProvider {
     );
   }
 
+  Future forgetPage(String path) async {
+    final db = await _ref.read(databaseProvider).database;
+    await db.delete(
+      CachedPage.kTableName,
+      where: 'url = ?',
+      whereArgs: [path],
+    );
+  }
+
   Future<String> fetchPage(String path) async {
     if (_cookie == null) await _updateCookie();
 
@@ -92,13 +102,16 @@ class PageProvider {
 
       if (response.statusCode != 200) {
         if (cached != null) return cached.content;
-        throw FetchError('Error on $path', response);
+        throw FetchError('Error', path, response);
       }
 
       body = utf8.decode(response.bodyBytes);
     } on TimeoutException {
       if (cached != null) return cached.content;
-      throw FetchError('Timeout for $path', null);
+      throw FetchError('Timeout', path);
+    }
+    if (body.length < 2) {
+      throw FetchError('Empty page', path);
     }
 
     _saveToCache(path, body);

lib/word.dart

@@ -99,10 +99,9 @@ class _WordViewState extends ConsumerState<WordView> {
   _updateMainPage() async {
     _error = null;
     _homonyms = const [];
+    final path = ref.read(linksProvider.notifier).search(widget.word.word);
     try {
-      final body = await ref
-          .read(pageProvider)
-          .fetchPage(ref.read(linksProvider.notifier).search(widget.word.word));
+      final body = await ref.read(pageProvider).fetchPage(path);
       _homonyms = SonaveebParsers.extractHomonyms(body);
     } on FetchError catch (e) {
       _logger.severe('Failed to fetch the word page', e);
@@ -113,6 +112,7 @@ class _WordViewState extends ConsumerState<WordView> {
     }
 
     if (_homonyms.isEmpty) {
+      ref.read(pageProvider).forgetPage(path);
       return;
     }
 

pubspec.lock

@@ -61,10 +61,10 @@ packages:
     dependency: transitive
     description:
       name: cli_util
-      sha256: c05b7406fdabc7a49a3929d4af76bcaccbbffcbcdcf185b082e1ae07da323d19
+      sha256: ff6785f7e9e3c38ac98b2fb035701789de90154024a75b6cb926445e83197d1c
       url: "https://pub.dev"
     source: hosted
-    version: "0.4.1"
+    version: "0.4.2"
   clock:
     dependency: transitive
     description:
@@ -93,10 +93,10 @@ packages:
     dependency: transitive
     description:
       name: csslib
-      sha256: "706b5707578e0c1b4b7550f64078f0a0f19dec3f50a178ffae7006b0a9ca58fb"
+      sha256: "09bad715f418841f976c77db72d5398dc1253c21fb9c0c7f0b0b985860b2d58e"
       url: "https://pub.dev"
     source: hosted
-    version: "1.0.0"
+    version: "1.0.2"
   fake_async:
     dependency: transitive
     description:
@@ -164,10 +164,10 @@ packages:
     dependency: "direct main"
     description:
       name: html
-      sha256: "3a7812d5bcd2894edf53dfaf8cd640876cf6cef50a8f238745c8b8120ea74d3a"
+      sha256: "1fc58edeaec4307368c60d59b7e15b9d658b57d7f3125098b6294153c75337ec"
       url: "https://pub.dev"
     source: hosted
-    version: "0.15.4"
+    version: "0.15.5"
   http:
     dependency: "direct main"
     description:
@@ -521,10 +521,10 @@ packages:
     dependency: transitive
     description:
       name: url_launcher_android
-      sha256: "0dea215895a4d254401730ca0ba8204b29109a34a99fb06ae559a2b60988d2de"
+      sha256: "6fc2f56536ee873eeb867ad176ae15f304ccccc357848b351f6f0d8d4a40d193"
       url: "https://pub.dev"
     source: hosted
-    version: "6.3.13"
+    version: "6.3.14"
   url_launcher_ios:
     dependency: transitive
     description:

pubspec.yaml

@@ -1,7 +1,7 @@
 name: sonamobi
 description: Mobile interface to Sonaveeb
 publish_to: 'none'
-version: 0.1.1+2
+version: 0.2.0+3
 
 environment:
   sdk: ^3.5.3