Initial Web support

example/pubspec.lock

@@ -74,6 +74,18 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_web_plugins:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  js:
+    dependency: transitive
+    description:
+      name: js
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.6.3"
   matcher:
     dependency: transitive
     description:

lib/flutter_audio_capture.dart

@@ -1,27 +1 @@
-import 'dart:async';
-
-import 'package:flutter/services.dart';
-
-const AUDIO_CAPTURE_EVENT_CHANNEL_NAME = "ymd.dev/audio_capture_event_channel";
-
-class FlutterAudioCapture {
-  final EventChannel _audioCaptureEventChannel =
-      EventChannel(AUDIO_CAPTURE_EVENT_CHANNEL_NAME);
-  StreamSubscription? _audioCaptureEventChannelSubscription;
-
-  Future<void> start(Function listener, Function onError,
-      {int sampleRate = 44000, int bufferSize = 5000}) async {
-    if (_audioCaptureEventChannelSubscription != null) return;
-    _audioCaptureEventChannelSubscription = _audioCaptureEventChannel
-        .receiveBroadcastStream({
-      "sampleRate": sampleRate,
-      "bufferSize": bufferSize
-    }).listen(listener as void Function(dynamic)?, onError: onError);
-  }
-
-  Future<void> stop() async {
-    if (_audioCaptureEventChannelSubscription == null) return;
-    _audioCaptureEventChannelSubscription!.cancel();
-    _audioCaptureEventChannelSubscription = null;
-  }
-}
+export 'native.dart' if (dart.library.html) 'web.dart';

lib/interface.dart

@@ -0,0 +1,10 @@
+class IAudioCapture {
+  Future<void> start(Function listener, Function onError,
+      {int sampleRate = 44000, int bufferSize = 5000}) async {
+    throw UnimplementedError();
+  }
+
+  Future<void> stop() async {
+    throw UnimplementedError();
+  }
+}

lib/native.dart

@@ -0,0 +1,30 @@
+import 'dart:async';
+
+import 'package:flutter/services.dart';
+import 'package:flutter_audio_capture/interface.dart';
+
+const AUDIO_CAPTURE_EVENT_CHANNEL_NAME = "ymd.dev/audio_capture_event_channel";
+
+class FlutterAudioCapture implements IAudioCapture {
+  final EventChannel _audioCaptureEventChannel =
+      EventChannel(AUDIO_CAPTURE_EVENT_CHANNEL_NAME);
+  StreamSubscription? _audioCaptureEventChannelSubscription;
+
+  @override
+  Future<void> start(Function listener, Function onError,
+      {int sampleRate = 44000, int bufferSize = 5000}) async {
+    if (_audioCaptureEventChannelSubscription != null) return;
+    _audioCaptureEventChannelSubscription = _audioCaptureEventChannel
+        .receiveBroadcastStream({
+      "sampleRate": sampleRate,
+      "bufferSize": bufferSize
+    }).listen(listener as void Function(dynamic)?, onError: onError);
+  }
+
+  @override
+  Future<void> stop() async {
+    if (_audioCaptureEventChannelSubscription == null) return;
+    _audioCaptureEventChannelSubscription!.cancel();
+    _audioCaptureEventChannelSubscription = null;
+  }
+}

lib/web.dart

@@ -0,0 +1,67 @@
+import 'dart:async';
+import 'dart:html';
+import 'dart:web_audio';
+import 'dart:typed_data';
+
+import 'package:flutter_audio_capture/interface.dart';
+
+class FlutterAudioCapture extends IAudioCapture {
+  StreamController<Float64List>? controller;
+
+  @override
+  Future<void> start(Function listener, Function onError,
+      {int sampleRate = 44000, int bufferSize = 5000}) async {
+    if (controller == null) {
+      controller = StreamController();
+      controller!.stream.listen((event) {
+        listener(event);
+      }, onError: (error) {
+        onError();
+      });
+      startRecording();
+    }
+  }
+
+  @override
+  Future<void> stop() async {
+    if (controller != null) {
+      await controller!.close();
+      controller = null;
+    }
+  }
+
+  Float64List _convertBytesToFloat64(dynamic buf) {
+    return Float64List.fromList(buf);
+  }
+
+  startRecording() async {
+    // build up stuff we need
+    final stream = await window.navigator.mediaDevices!
+        .getUserMedia({"audio": true, "video": false});
+    final context = AudioContext();
+    final source = context.createMediaStreamSource(stream);
+    final processor = context.createScriptProcessor(4096, 1, 1);
+    source.connectNode(processor);
+    processor.connectNode(context.destination!);
+    final audioStream = processor.onAudioProcess;
+    var closed = false;
+    audioStream.listen((e) async {
+      var sr = e.inputBuffer!.sampleRate;
+      var buf = e.inputBuffer!.getChannelData(0);
+      if (controller != null &&
+          !controller!.isClosed &&
+          !controller!.isPaused &&
+          !closed) {
+        try {
+          controller!.add(_convertBytesToFloat64(buf));
+        } catch (e) {}
+      } else {
+        // cancel recording stuff...
+        if (!closed) {
+          closed = true;
+          await context.close();
+        }
+      }
+    });
+  }
+}

pubspec.lock

@@ -151,13 +151,25 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_web_plugins:
+    dependency: "direct main"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   glob:
     dependency: transitive
     description:
       name: glob
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.1"
+  js:
+    dependency: transitive
+    description:
+      name: js
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.6.3"
   logging:
     dependency: transitive
     description:

pubspec.yaml

@@ -10,6 +10,8 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
+  flutter_web_plugins:
+    sdk: flutter
 
 dev_dependencies:
   mockito: ^5.0.5
@@ -20,8 +22,8 @@ flutter:
   plugin:
     platforms:
       android:
-        package: com.ymd.flutter_audio_capture
         pluginClass: FlutterAudioCapturePlugin
+        package: com.ymd.flutter_audio_capture
       ios: 
         pluginClass: FlutterAudioCapturePlugin
       linux: