api: Send simple User-Agent header

lib/api/core.dart

@@ -74,12 +74,16 @@ class ApiConnection {
   bool _isOpen = true;
 
   Future<T> send<T>(String routeName, T Function(Map<String, dynamic>) fromJson,
-      http.BaseRequest request) async {
+      http.BaseRequest request, {String? overrideUserAgent}) async {
     assert(_isOpen);
 
     assert(debugLog("${request.method} ${request.url}"));
 
     addAuth(request);
+    request.headers.addAll(userAgentHeader());
+    if (overrideUserAgent != null) {
+      request.headers['User-Agent'] = overrideUserAgent;
+    }
 
     final http.StreamedResponse response;
     try {
@@ -136,13 +140,13 @@ class ApiConnection {
   }
 
   Future<T> post<T>(String routeName, T Function(Map<String, dynamic>) fromJson,
-      String path, Map<String, dynamic>? params) async {
+      String path, Map<String, dynamic>? params, {String? overrideUserAgent}) async {
     final url = realmUrl.replace(path: "/api/v1/$path");
     final request = http.Request('POST', url);
     if (params != null) {
       request.bodyFields = encodeParameters(params)!;
     }
-    return send(routeName, fromJson, request);
+    return send(routeName, fromJson, request, overrideUserAgent: overrideUserAgent);
   }
 
   Future<T> postFileFromStream<T>(String routeName, T Function(Map<String, dynamic>) fromJson,
@@ -201,6 +205,13 @@ Map<String, String> authHeader({required String email, required String apiKey})
   };
 }
 
+Map<String, String> userAgentHeader() {
+  return {
+    // TODO(#467) include platform, platform version, and app version
+    'User-Agent': 'ZulipFlutter',
+  };
+}
+
 Map<String, String>? encodeParameters(Map<String, dynamic>? params) {
   return params?.map((k, v) =>
     MapEntry(k, v is RawParameter ? v.value : jsonEncode(v)));

lib/api/route/messages.dart

@@ -180,6 +180,7 @@ Future<SendMessageResult> sendMessage(
   bool? readBySender,
 }) {
   final supportsTypeDirect = connection.zulipFeatureLevel! >= 174; // TODO(server-7)
+  final supportsReadBySender = connection.zulipFeatureLevel! >= 236; // TODO(server-8)
   return connection.post('sendMessage', SendMessageResult.fromJson, 'messages', {
     if (destination is StreamDestination) ...{
       'type': RawParameter('stream'),
@@ -195,6 +196,23 @@ Future<SendMessageResult> sendMessage(
     if (queueId != null) 'queue_id': queueId, // TODO should this use RawParameter?
     if (localId != null) 'local_id': localId, // TODO should this use RawParameter?
     if (readBySender != null) 'read_by_sender': readBySender,
+  },
+  overrideUserAgent: switch ((supportsReadBySender, readBySender)) {
+    // Old servers use the user agent to decide if we're a UI client
+    // and so whether the message should be marked as read for its author
+    // (see #440). We are a UI client; so, use a value those servers will
+    // interpret correctly. With newer servers, passing `readBySender: true`
+    // gives the same result.
+    // TODO(#467) include platform, platform version, and app version
+    (false, _   ) => 'ZulipMobile/flutter',
+
+    // According to the doc, a user-agent heuristic is still used in this case:
+    //   https://zulip.com/api/send-message#parameter-read_by_sender
+    // TODO find out if our default user agent would work with that.
+    // TODO(#467) include platform, platform version, and app version
+    (true,  null) => 'ZulipMobile/flutter',
+
+    _             => null,
   });
 }
 

lib/widgets/content.dart

@@ -848,12 +848,13 @@ class RealmContentNetworkImage extends StatelessWidget {
       gaplessPlayback: gaplessPlayback,
       filterQuality: filterQuality,
       isAntiAlias: isAntiAlias,
-
-      // Only send the auth header to the server `auth` belongs to.
-      headers: src.origin == account.realmUrl.origin
-        ? authHeader(email: account.email, apiKey: account.apiKey)
-        : null,
-
+      headers: {
+        // Only send the auth header to the server `auth` belongs to.
+        if (src.origin == account.realmUrl.origin) ...authHeader(
+          email: account.email, apiKey: account.apiKey,
+        ),
+        ...userAgentHeader(),
+      },
       cacheWidth: cacheWidth,
       cacheHeight: cacheHeight,
     );

test/api/core_test.dart

@@ -22,7 +22,10 @@ void main() {
         check(connection.lastRequest!).isA<http.Request>()
           ..method.equals('GET')
           ..url.asString.equals('${eg.realmUrl.origin}$expectedRelativeUrl')
-          ..headers.deepEquals(authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey))
+          ..headers.deepEquals({
+            ...authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey),
+            ...userAgentHeader(),
+          })
           ..body.equals('');
       });
     }
@@ -52,6 +55,7 @@ void main() {
           ..url.asString.equals('${eg.realmUrl.origin}/api/v1/example/route')
           ..headers.deepEquals({
             ...authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey),
+            ...userAgentHeader(),
             if (expectContentType)
               'content-type': 'application/x-www-form-urlencoded; charset=utf-8',
           })
@@ -82,7 +86,10 @@ void main() {
         check(connection.lastRequest!).isA<http.MultipartRequest>()
           ..method.equals('POST')
           ..url.asString.equals('${eg.realmUrl.origin}/api/v1/example/route')
-          ..headers.deepEquals(authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey))
+          ..headers.deepEquals({
+            ...authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey),
+            ...userAgentHeader(),
+          })
           ..fields.deepEquals({})
           ..files.single.which((it) => it
             ..field.equals('file')
@@ -114,6 +121,7 @@ void main() {
           ..url.asString.equals('${eg.realmUrl.origin}/api/v1/example/route')
           ..headers.deepEquals({
             ...authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey),
+            ...userAgentHeader(),
             if (expectContentType)
               'content-type': 'application/x-www-form-urlencoded; charset=utf-8',
           })

test/api/route/messages_test.dart

@@ -3,6 +3,7 @@ import 'dart:convert';
 import 'package:checks/checks.dart';
 import 'package:http/http.dart' as http;
 import 'package:test/scaffolding.dart';
+import 'package:zulip/api/core.dart';
 import 'package:zulip/api/model/model.dart';
 import 'package:zulip/api/model/narrow.dart';
 import 'package:zulip/api/route/messages.dart';
@@ -304,6 +305,7 @@ void main() {
       String? localId,
       bool? readBySender,
       required Map<String, String> expectedBodyFields,
+      String? expectedUserAgent,
     }) async {
       connection.prepare(json: SendMessageResult(id: 42).toJson());
       final result = await sendMessage(connection,
@@ -313,7 +315,8 @@ void main() {
       check(connection.lastRequest).isA<http.Request>()
         ..method.equals('POST')
         ..url.path.equals('/api/v1/messages')
-        ..bodyFields.deepEquals(expectedBodyFields);
+        ..bodyFields.deepEquals(expectedBodyFields)
+        ..headers['User-Agent'].equals(expectedUserAgent ?? userAgentHeader()['User-Agent']!);
     }
 
     test('smoke', () {
@@ -339,11 +342,13 @@ void main() {
       return FakeApiConnection.with_((connection) async {
         await checkSendMessage(connection,
           destination: StreamDestination(streamId, topic), content: content,
+          readBySender: true,
           expectedBodyFields: {
             'type': 'stream',
             'to': streamId.toString(),
             'topic': topic,
             'content': content,
+            'read_by_sender': 'true',
           });
       });
     });
@@ -352,10 +357,12 @@ void main() {
       return FakeApiConnection.with_((connection) async {
         await checkSendMessage(connection,
           destination: DmDestination(userIds: userIds), content: content,
+          readBySender: true,
           expectedBodyFields: {
             'type': 'direct',
             'to': jsonEncode(userIds),
             'content': content,
+            'read_by_sender': 'true',
           });
       });
     });
@@ -364,11 +371,45 @@ void main() {
       return FakeApiConnection.with_(zulipFeatureLevel: 173, (connection) async {
         await checkSendMessage(connection,
           destination: DmDestination(userIds: userIds), content: content,
+          readBySender: true,
           expectedBodyFields: {
             'type': 'private',
             'to': jsonEncode(userIds),
             'content': content,
-          });
+            'read_by_sender': 'true',
+          },
+          expectedUserAgent: 'ZulipMobile/flutter');
+      });
+    });
+
+    test('when readBySender is null, sends a User-Agent we know the server will recognize', () {
+      return FakeApiConnection.with_((connection) async {
+        await checkSendMessage(connection,
+          destination: StreamDestination(streamId, topic), content: content,
+          readBySender: null,
+          expectedBodyFields: {
+            'type': 'stream',
+            'to': streamId.toString(),
+            'topic': topic,
+            'content': content,
+          },
+          expectedUserAgent: 'ZulipMobile/flutter');
+      });
+    });
+
+    test('legacy: when server does not support readBySender, sends a User-Agent the server will recognize', () {
+      return FakeApiConnection.with_(zulipFeatureLevel: 235, (connection) async {
+        await checkSendMessage(connection,
+          destination: StreamDestination(streamId, topic), content: content,
+          readBySender: true,
+          expectedBodyFields: {
+            'type': 'stream',
+            'to': streamId.toString(),
+            'topic': topic,
+            'content': content,
+            'read_by_sender': 'true',
+          },
+          expectedUserAgent: 'ZulipMobile/flutter');
       });
     });
   });

test/widgets/content_test.dart

@@ -285,7 +285,7 @@ void main() {
   group('RealmContentNetworkImage', () {
     final authHeaders = authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey);
 
-    Future<String?> actualAuthHeader(WidgetTester tester, Uri src) async {
+    Future<Map<String, List<String>>> actualHeaders(WidgetTester tester, Uri src) async {
       await testBinding.globalStore.add(eg.selfAccount, eg.initialSnapshot());
       addTearDown(testBinding.reset);
 
@@ -301,20 +301,21 @@ void main() {
       await tester.pump();
       await tester.pump();
 
-      final headers = httpClient.request.headers.values;
-      check(authHeaders.keys).deepEquals(['Authorization']);
-      return headers['Authorization']?.single;
+      return httpClient.request.headers.values;
     }
 
     testWidgets('includes auth header if `src` on-realm', (tester) async {
-      check(await actualAuthHeader(tester, Uri.parse('https://chat.example/image.png')))
-        .isNotNull().equals(authHeaders['Authorization']!);
+      check(await actualHeaders(tester, Uri.parse('https://chat.example/image.png')))
+        .deepEquals({
+          'Authorization': [authHeaders['Authorization']!],
+          'User-Agent': [userAgentHeader()['User-Agent']!],
+        });
       debugNetworkImageHttpClientProvider = null;
     });
 
     testWidgets('excludes auth header if `src` off-realm', (tester) async {
-      check(await actualAuthHeader(tester, Uri.parse('https://other.example/image.png')))
-        .isNull();
+      check(await actualHeaders(tester, Uri.parse('https://other.example/image.png')))
+        .deepEquals({'User-Agent': [userAgentHeader()['User-Agent']!]});
       debugNetworkImageHttpClientProvider = null;
     });