feat: make cancellation more stable

Tienisto · Nov 4, 2024 · 76fbe21 · 76fbe21
1 parent 8c458df
commit 76fbe21
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Showing 3 changed files with 128 additions and 10 deletions.
diff --git a/rhttp/example/lib/cancellation.dart b/rhttp/example/lib/cancellation.dart
@@ -2,6 +2,7 @@
 
 import 'package:flutter/material.dart';
 import 'package:rhttp/rhttp.dart';
+import 'package:rhttp_example/widgets/response_card.dart';
 
 Future<void> main() async {
   await Rhttp.init();
@@ -43,8 +44,7 @@ class _MyAppState extends State<MyApp> {
                     );
                     final resFuture = client!.requestBytes(
                       method: HttpMethod.get,
-                      url:
-                          'https://github.com/localsend/localsend/releases/download/v1.15.3/LocalSend-1.15.3-linux-x86-64.AppImage',
+                      url: 'https://github.com/localsend/localsend/releases/download/v1.15.3/LocalSend-1.15.3-linux-x86-64.AppImage',
                       cancelToken: cancelToken,
                     );
 
@@ -62,11 +62,111 @@ class _MyAppState extends State<MyApp> {
                     print(e);
                   }
                 },
-                child: const Text('Test'),
+                child: const Text('Cancel after 1 second'),
               ),
-              if (response != null) Text(response!.version.toString()),
-              if (response != null) Text(response!.statusCode.toString()),
-              if (response != null) Text(response!.headers.toString()),
+              ElevatedButton(
+                onPressed: () async {
+                  try {
+                    final cancelToken = CancelToken();
+                    client ??= await RhttpClient.create(
+                      settings: const ClientSettings(
+                        timeoutSettings: TimeoutSettings(
+                          timeout: Duration(seconds: 10),
+                        ),
+                      ),
+                    );
+                    final resFuture = client!.requestBytes(
+                      method: HttpMethod.get,
+                      url: 'https://github.com/localsend/localsend/releases/download/v1.15.3/LocalSend-1.15.3-linux-x86-64.AppImage',
+                      cancelToken: cancelToken,
+                    );
+
+                    await cancelToken.cancel();
+
+                    final res = await resFuture;
+
+                    setState(() {
+                      response = res;
+                    });
+                  } catch (e) {
+                    print(e);
+                  }
+                },
+                child: const Text('Cancel immediately'),
+              ),
+              ElevatedButton(
+                onPressed: () async {
+                  try {
+                    final cancelToken = CancelToken();
+                    client ??= await RhttpClient.create(
+                      settings: const ClientSettings(
+                        timeoutSettings: TimeoutSettings(
+                          timeout: Duration(seconds: 10),
+                        ),
+                      ),
+                    );
+                    final resFuture = client!.requestBytes(
+                      method: HttpMethod.get,
+                      url: 'https://github.com/localsend/localsend/releases/download/v1.15.3/LocalSend-1.15.3-linux-x86-64.AppImage',
+                      cancelToken: cancelToken,
+                    );
+
+                    await cancelToken.cancel();
+                    await cancelToken.cancel();
+
+                    final res = await resFuture;
+
+                    setState(() {
+                      response = res;
+                    });
+                  } catch (e) {
+                    print(e);
+                  }
+                },
+                child: const Text('Cancel multiple times'),
+              ),
+              ElevatedButton(
+                onPressed: () async {
+                  final cancelToken = CancelToken();
+                  client ??= await RhttpClient.create(
+                    settings: const ClientSettings(
+                      timeoutSettings: TimeoutSettings(
+                        timeout: Duration(seconds: 10),
+                      ),
+                    ),
+                  );
+
+                  final resFuture = client!.requestBytes(
+                    method: HttpMethod.get,
+                    url: 'https://github.com/localsend/localsend/releases/download/v1.15.3/LocalSend-1.15.3-linux-x86-64.AppImage',
+                    cancelToken: cancelToken,
+                  );
+
+                  final resFuture2 = client!.requestBytes(
+                    method: HttpMethod.get,
+                    url: 'https://github.com/localsend/localsend/releases/download/v1.16.0/LocalSend-1.16.0-linux-x86-64.AppImage',
+                    cancelToken: cancelToken,
+                  );
+
+                  Future.delayed(const Duration(seconds: 1), () async {
+                    await cancelToken.cancel();
+                  });
+
+                  try {
+                    await resFuture;
+                  } catch (e) {
+                    print(e);
+                  }
+
+                  try {
+                    await resFuture2;
+                  } catch (e) {
+                    print(e);
+                  }
+                },
+                child: const Text('Cancel multiple requests'),
+              ),
+              if (response != null) ResponseCard(response: response!),
             ],
           ),
         ),

diff --git a/rhttp/example/pubspec.lock b/rhttp/example/pubspec.lock
@@ -272,7 +272,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "0.8.1"
+    version: "0.9.1"
   riverpod:
     dependency: transitive
     description:

diff --git a/rhttp/lib/src/model/cancel_token.dart b/rhttp/lib/src/model/cancel_token.dart
@@ -13,18 +13,26 @@ import 'package:rhttp/src/rust/lib.dart' as rust_lib;
 /// If a cancelled token is passed to a request method,
 /// the request is cancelled immediately.
 class CancelToken {
-  final _refController =
-      StreamController<rust_lib.CancellationToken>.broadcast();
+  final _refController = StreamController<rust_lib.CancellationToken>();
+  final _firstRef = Completer<rust_lib.CancellationToken>();
   final _refs = <rust_lib.CancellationToken>[];
 
   bool _isCancelled = false;
 
+  /// Whether the cancellation process has started.
+  /// This is different from [isCancelled] because otherwise,
+  /// we would not receive the stream event.
+  bool _lock = false;
+
   /// Whether the request has been cancelled.
   bool get isCancelled => _isCancelled;
 
   CancelToken() {
     _refController.stream.listen((ref) {
       _refs.add(ref);
+      if (_refs.length == 1) {
+        _firstRef.complete(ref);
+      }
     });
   }
 
@@ -41,13 +49,23 @@ class CancelToken {
   /// If the [CancelToken] is not passed to the request method,
   /// this method never finishes.
   Future<void> cancel() async {
+    if (_isCancelled) {
+      return;
+    }
+
+    if (_lock) {
+      return;
+    }
+
+    _lock = true;
+
     if (_refs.isNotEmpty) {
       for (final ref in _refs) {
         await rust.cancelRequest(token: ref);
       }
     } else {
       // We need to wait for the ref to be set.
-      final ref = await _refController.stream.first;
+      final ref = await _firstRef.future;
       await rust.cancelRequest(token: ref);
     }