Added size support to Network tab

packages/devtools_app/lib/src/screens/network/network_model.dart

@@ -29,6 +29,9 @@ abstract class NetworkRequest
 
   int? get port;
 
+  int? get requestBytes => null;
+  int? get responseBytes => null;
+
   bool get didFail;
 
   /// True if the request hasn't completed yet.
@@ -160,6 +163,12 @@ class Socket extends NetworkRequest {
   @override
   int get port => _socket.port;
 
+  @override
+  int get requestBytes => writeBytes;
+
+  @override
+  int get responseBytes => readBytes;
+
   // TODO(kenz): what determines a web socket request failure?
   @override
   bool get didFail => false;

packages/devtools_app/lib/src/screens/network/network_request_inspector_views.dart

@@ -17,6 +17,7 @@ import '../../shared/ui/colors.dart';
 import '../../shared/ui/common_widgets.dart';
 import 'network_controller.dart';
 import 'network_model.dart';
+import 'utils/http_utils.dart';
 
 // Approximately double the indent of the expandable tile's title.
 const _rowIndentPadding = 30.0;
@@ -625,6 +626,7 @@ class NetworkRequestOverviewView extends StatelessWidget {
   }
 
   List<Widget> _buildGeneralRows(BuildContext context) {
+    final bytes = data.responseBytes;
     return [
       // TODO(kenz): show preview for requests (png, response body, proto)
       _buildRow(
@@ -658,6 +660,14 @@ class NetworkRequestOverviewView extends StatelessWidget {
         ),
         const SizedBox(height: defaultSpacing),
       ],
+
+      _buildRow(
+        context: context,
+        title: 'Response Size',
+        child: _valueText(bytes != null ? formatBytes(bytes) : '-'),
+      ),
+      const SizedBox(height: defaultSpacing),
+
       if (data.contentType != null) ...[
         _buildRow(
           context: context,

packages/devtools_app/lib/src/screens/network/network_screen.dart

@@ -30,6 +30,7 @@ import '../../shared/ui/utils.dart';
 import 'network_controller.dart';
 import 'network_model.dart';
 import 'network_request_inspector.dart';
+import 'utils/http_utils.dart';
 
 class NetworkScreen extends Screen {
   NetworkScreen() : super.fromMetaData(ScreenMetaData.network);
@@ -363,6 +364,7 @@ class NetworkRequestsTable extends StatelessWidget {
   static const statusColumn = StatusColumn();
   static const typeColumn = TypeColumn();
   static const durationColumn = DurationColumn();
+  static const responseSizeColumn = ResponseSizeColumn();
   static final timestampColumn = TimestampColumn();
   static const actionsColumn = ActionsColumn();
   static final columns = <ColumnData<NetworkRequest>>[
@@ -371,6 +373,7 @@ class NetworkRequestsTable extends StatelessWidget {
     statusColumn,
     typeColumn,
     durationColumn,
+    responseSizeColumn,
     timestampColumn,
     actionsColumn,
   ];
@@ -405,6 +408,20 @@ class NetworkRequestsTable extends StatelessWidget {
   }
 }
 
+class ResponseSizeColumn extends ColumnData<NetworkRequest> {
+  const ResponseSizeColumn()
+    : super('Size', alignment: ColumnAlignment.right, fixedWidthPx: 90);
+
+  @override
+  int? getValue(NetworkRequest dataObject) => dataObject.responseBytes;
+
+  @override
+  String getDisplayValue(NetworkRequest dataObject) {
+    final bytes = dataObject.responseBytes;
+    return bytes != null ? formatBytes(bytes) : '-';
+  }
+}
+
 class AddressColumn extends ColumnData<NetworkRequest>
     implements ColumnRenderer<NetworkRequest> {
   AddressColumn()

packages/devtools_app/lib/src/screens/network/utils/http_utils.dart

@@ -29,3 +29,18 @@ int calculateHeadersSize(Map<String, Object?>? headers) {
   // Calculate the byte length of the headers string
   return utf8.encode(headersString).length;
 }
+
+// Output Formats:
+// - 512 → "512 B"
+// - 2000 → "2.0 kB"
+// - 1000000 → "1.0 MB"
+// Values are rounded to one decimal place for kB and MB.
+// Uses decimal (base-10) units to match Chrome DevTools.
+String formatBytes(int? bytes) {
+  if (bytes == null || bytes < 0) return '-';
+  if (bytes < 1000) return '$bytes B';
+  if (bytes < 1000 * 1000) {
+    return '${(bytes / 1000).toStringAsFixed(1)} kB';
+  }
+  return '${(bytes / (1000 * 1000)).toStringAsFixed(1)} MB';
+}

packages/devtools_app/lib/src/shared/http/http_request_data.dart

@@ -227,6 +227,26 @@ class DartIOHttpRequestData extends NetworkRequest {
     return connectionInfo != null ? connectionInfo[_localPortKey] : null;
   }
 
+  @override
+  int? get responseBytes {
+    final contentLength = responseHeaders?['content-length'];
+
+    if (contentLength is String) {
+      return int.tryParse(contentLength);
+    }
+    if (contentLength is List && contentLength.isNotEmpty) {
+      final first = contentLength.first;
+
+      if (first is int) {
+        return first;
+      }
+      if (first is String) {
+        return int.tryParse(first);
+      }
+    }
+    return null;
+  }
+
   /// True if the HTTP request hasn't completed yet, determined by the lack of
   /// an end time in the response data.
   @override

packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md

@@ -39,6 +39,9 @@ TODO: Remove this section if there are not any updates.
 
 ## Network profiler updates
 
+- Added response size column to the Network tab and displayed response size in the request inspector overview. -
+  [#9744](https://github.com/flutter/devtools/pull/9744)
+
 - Added a filter setting to hide HTTP-profiler socket data. [#9698](https://github.com/flutter/devtools/pull/9698)
 
 ## Logging updates

packages/devtools_app/test/shared/http/http_request_data_test.dart

@@ -0,0 +1,70 @@
+import 'package:devtools_app/src/shared/http/http_request_data.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('responseBytes', () {
+    Map<String, dynamic> baseJson(Map<String, Object?> headers) {
+      return {
+        'method': 'GET',
+        'uri': 'https://example.com',
+        'status': 200,
+        'responseHeaders': headers,
+      };
+    }
+
+    // Verifies parsing when content-length is a string value.
+    test('parses content-length from string', () {
+      final request = DartIOHttpRequestData.fromJson(
+        baseJson({'content-length': '1234'}),
+        null, // requestPostData not used for this test
+        null, // responseContent not used for this test
+      );
+
+      expect(request.responseBytes, 1234);
+    });
+
+    // Verifies parsing when content-length is a list of strings.
+    test('parses content-length from list of strings', () {
+      final request = DartIOHttpRequestData.fromJson(
+        baseJson({'content-length': '5678'}),
+        null, // requestPostData not used for this test
+        null, // responseContent not used for this test
+      );
+
+      expect(request.responseBytes, 5678);
+    });
+
+    // Ensures integer values inside a list are handled correctly.
+    test('handles integer in list', () {
+      final request = DartIOHttpRequestData.fromJson(
+        baseJson({'content-length': '91011'}),
+        null, // requestPostData not used for this test
+        null, // responseContent not used for this test
+      );
+
+      expect(request.responseBytes, 91011);
+    });
+
+    // Returns null when header is missing.
+    test('returns null for missing header', () {
+      final request = DartIOHttpRequestData.fromJson(
+        baseJson({}), // No content-length header
+        null, // requestPostData not used for this test
+        null, // responseContent not used for this test
+      );
+
+      expect(request.responseBytes, null);
+    });
+
+    // Returns null when parsing fails.
+    test('returns null for invalid value', () {
+      final request = DartIOHttpRequestData.fromJson(
+        baseJson({'content-length': 'invalid'}),
+        null, // requestPostData not used for this test
+        null, // responseContent not used for this test
+      );
+
+      expect(request.responseBytes, null);
+    });
+  });
+}

packages/devtools_app/test/shared/http/http_utils_test.dart

@@ -0,0 +1,19 @@
+import 'package:devtools_app/src/screens/network/utils/http_utils.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('formatBytes', () {
+    // Verifies correct formatting across different unit ranges.
+    test('formats bytes correctly', () {
+      expect(formatBytes(512), '512 B'); // bytes
+      expect(formatBytes(2000), '2.0 kB'); // kilobytes (base-10)
+      expect(formatBytes(1000000), '1.0 MB'); // megabytes (base-10)
+    });
+
+    // Ensures handling of invalid or missing values.
+    test('handles null and negative values', () {
+      expect(formatBytes(null), '-');
+      expect(formatBytes(-1), '-');
+    });
+  });
+}