Ref: execute before send callback

CHANGELOG.md

@@ -32,6 +32,7 @@
 - Ref: Remove stackFrameFilter in favor of beforeSendCallback #125
 - Ref: added Transport #123
 - Feat: apply sample rate
+- Ref: execute before send callback
 
 # `package:sentry` changelog
 

dart/lib/src/client.dart

@@ -35,15 +35,22 @@ abstract class SentryClient {
     Scope scope,
     dynamic hint,
   }) async {
+    final emptyFuture = Future.value(SentryId.empty());
+
     event = _processEvent(event, eventProcessors: _options.eventProcessors);
 
     // dropped by sampling or event processors
     if (event == null) {
-      return Future.value(SentryId.empty());
+      return emptyFuture;
     }
 
     event = _applyScope(event: event, scope: scope);
 
+    // dropped by scope event processors
+    if (event == null) {
+      return emptyFuture;
+    }
+
     // TODO create eventProcessors ?
     event = event.copyWith(
       serverName: _options.serverName,
@@ -52,6 +59,21 @@ abstract class SentryClient {
       platform: event.platform ?? sdkPlatform,
     );
 
+    if (_options.beforeSendCallback != null) {
+      try {
+        event = _options.beforeSendCallback(event, hint);
+      } catch (err) {
+        _options.logger(
+          SentryLevel.error,
+          'The BeforeSend callback threw an exception',
+        );
+      }
+      if (event == null) {
+        _options.logger(SentryLevel.debug, 'Event was dropped by a processor');
+        return emptyFuture;
+      }
+    }
+
     return _options.transport.send(event);
   }
 
@@ -160,6 +182,8 @@ abstract class SentryClient {
       if (scope.level != null) {
         event = event.copyWith(level: scope.level);
       }
+
+      // TODO: execute scope event processors
     }
     return event;
   }

dart/test/sentry_client_test.dart

@@ -7,38 +7,64 @@ import 'mocks.dart';
 void main() {
   group('SentryClient sampling', () {
     SentryOptions options;
-    Transport transport;
 
     setUp(() {
       options = SentryOptions(dsn: fakeDsn);
-      transport = MockTransport();
+      options.transport = MockTransport();
     });
 
     test('captures event, sample rate is 100% enabled', () {
       options.sampleRate = 1.0;
       final client = SentryClient(options);
-      options.transport = transport;
       client.captureEvent(fakeEvent);
 
-      verify(transport.send(any)).called(1);
+      verify(options.transport.send(any)).called(1);
     });
 
     test('do not capture event, sample rate is 0% disabled', () {
       options.sampleRate = 0.0;
       final client = SentryClient(options);
-      options.transport = transport;
       client.captureEvent(fakeEvent);
 
-      verifyNever(transport.send(any));
+      verifyNever(options.transport.send(any));
     });
 
     test('captures event, sample rate is null, disabled', () {
       options.sampleRate = null;
       final client = SentryClient(options);
-      options.transport = transport;
       client.captureEvent(fakeEvent);
 
-      verify(transport.send(any)).called(1);
+      verify(options.transport.send(any)).called(1);
+    });
+  });
+
+  group('SentryClient before send', () {
+    SentryOptions options;
+
+    setUp(() {
+      options = SentryOptions(dsn: fakeDsn);
+      options.transport = MockTransport();
+    });
+
+    test('before send drops event', () {
+      options.beforeSendCallback = beforeSendCallbackDropEvent;
+      final client = SentryClient(options);
+      client.captureEvent(fakeEvent);
+
+      verifyNever(options.transport.send(any));
+    });
+
+    test('before send returns an event and event is captured', () {
+      options.beforeSendCallback = beforeSendCallback;
+      final client = SentryClient(options);
+      client.captureEvent(fakeEvent);
+
+      verify(options.transport.send(any)).called(1);
     });
   });
 }
+
+SentryEvent beforeSendCallbackDropEvent(SentryEvent event, dynamic hint) =>
+    null;
+
+SentryEvent beforeSendCallback(SentryEvent event, dynamic hint) => event;