Headers emulation and setHeaders method to update headers (#92)

.github/workflows/ci.yaml

@@ -25,7 +25,7 @@ jobs:
         run: sudo gem install coveralls-lcov 
 
       - name: Start Centrifugo
-        run: docker run -d -p 8000:8000 centrifugo/centrifugo:latest centrifugo --client_insecure
+        run: docker run -d -p 8000:8000 centrifugo/centrifugo:v6 centrifugo --client.insecure
 
       - name: Run tests
         run: bash tool/test.sh

example/chat_app/lib/client/client.dart

@@ -31,8 +31,8 @@ class ChatClient {
       url,
       ClientConfig(
         token: conf.userJwtToken,
-        headers: <String, dynamic>{
-          'user-id': chatUserId,
+        headers: <String, String>{
+          'user-id': chatUserId.toString(),
           'user-name': chatUserName,
         },
       ),

example/console/example.dart

@@ -24,8 +24,10 @@ void main() async {
         url,
         centrifuge.ClientConfig(
           token: userJwtToken,
-          // Headers are only supported on platforms that support dart:io
-          headers: <String, dynamic>{'X-Example-Header': 'example'},
+          // If you want to use Headers in web environment – make sure your headers use
+          // string values, centrifuge-dart will then automatically attach them to connect
+          // frame (using Headers Emulation feature).
+          headers: <String, String>{'X-Example-Header': 'example'},
         ));
 
     // State changes.

example/web_app/pubspec.yaml

@@ -10,6 +10,7 @@ environment:
 dependencies:
   centrifuge:
     path: ../../
+  web: ^1.1.0
 
 publish_to: none
 

example/web_app/web/main.dart

@@ -1,18 +1,20 @@
-import 'dart:html';
+import 'package:web/web.dart' as web;
 
 import 'package:centrifuge/centrifuge.dart';
 
 void main() {
-  querySelector('#output')?.text = 'Your Dart app is running.';
+  web.document.querySelector('#output')?.text = 'Your Dart app is running.';
 
   void onEvent(dynamic event) {
-    querySelector('#output')?.text = 'client> $event';
+    web.document.querySelector('#output')?.text = 'client> $event';
   }
 
   const url = 'ws://localhost:8000/connection/websocket';
   Client client = createClient(
     url,
-    ClientConfig(),
+    ClientConfig(
+      headers: <String, String>{'Authorization': 'example'},
+    ),
   );
 
   // State changes.

lib/src/client.dart

@@ -7,6 +7,7 @@ import 'package:centrifuge/src/server_subscription.dart';
 import 'package:centrifuge/src/transport.dart';
 import 'package:meta/meta.dart';
 
+import 'platform/vm.dart' if (dart.library.js_interop) 'platform/js.dart';
 import 'proto/client.pb.dart' as protocol;
 import 'subscription.dart';
 
@@ -50,6 +51,10 @@ abstract class Client {
   ///
   void setToken(String token);
 
+  /// Set allows updating connection headers.
+  ///
+  void setHeaders(Map<String, String> headers);
+
   /// Ready resolves when client successfully connected.
   /// Throws exceptions if called not in connecting or connected state.
   Future<void> ready();
@@ -101,6 +106,7 @@ class ClientImpl implements Client {
   ClientImpl(this._url, this._config, this._transportBuilder) {
     _token = _config.token;
     _data = _config.data;
+    _headers = Map<String, String>.of(_config.headers);
   }
 
   final TransportBuilder _transportBuilder;
@@ -113,6 +119,7 @@ class ClientImpl implements Client {
   ClientConfig _config;
   ClientConfig get config => _config;
 
+  Map<String, String> _headers = {};
   String _token = '';
   List<int>? _data;
   String? _client;
@@ -197,6 +204,11 @@ class ClientImpl implements Client {
     _token = token;
   }
 
+  @override
+  void setHeaders(Map<String, String> headers) {
+    _headers = Map<String, String>.of(headers);
+  }
+
   @override
   Future<void> disconnect() async {
     _reconnectAttempts = 0;
@@ -422,8 +434,8 @@ class ClientImpl implements Client {
       return;
     }
 
-    final transport = _transportBuilder(
-        url: _url, config: TransportConfig(headers: _config.headers, timeout: _config.timeout));
+    final transport =
+        _transportBuilder(url: _url, config: TransportConfig(headers: _headers, timeout: _config.timeout));
 
     try {
       await transport.open(_onPush, onError: (dynamic error) {
@@ -470,6 +482,11 @@ class ClientImpl implements Client {
     request.name = _config.name;
     request.version = _config.version;
 
+    if (isWeb) {
+      // Use headers emulation in web context.
+      request.headers.addAll(_headers);
+    }
+
     if (_serverSubs.isNotEmpty) {
       _serverSubs.forEach((key, value) {
         final subRequest = protocol.SubscribeRequest();
@@ -560,7 +577,7 @@ class ClientImpl implements Client {
           _inConnect = false;
           return;
         } else {
-          _processDisconnect(code: err.code, reason: err.message, reconnect: false);
+          _processDisconnect(code: err.code, reason: err.message, reconnect: true);
           await transport.close();
           _inConnect = false;
           return;

lib/src/client_config.dart

@@ -14,7 +14,7 @@ class ClientConfig {
     this.getToken,
     this.data,
     this.getData,
-    this.headers = const <String, dynamic>{},
+    this.headers = const <String, String>{},
     this.tlsSkipVerify = false,
     this.timeout = const Duration(seconds: 10),
     this.minReconnectDelay = const Duration(milliseconds: 500),
@@ -41,8 +41,10 @@ class ClientConfig {
 
   /// Headers that are set when connecting the web socket on dart:io platforms.
   ///
-  /// Note that headers are ignored on the web platform.
-  final Map<String, dynamic> headers;
+  /// Note that headers on the web platform use Headers Emulation (since Centrifugo v6)
+  /// – i.e. headers are sent to Centrifugo in first protocol message but then automatically
+  /// translated to HTTP headers by Centrifugo in the proxy request to the backend.
+  final Map<String, String> headers;
 
   final bool tlsSkipVerify;
   final Duration minReconnectDelay;

lib/src/platform/js.dart

@@ -0,0 +1 @@
+bool get isWeb => true;

lib/src/platform/vm.dart

@@ -0,0 +1 @@
+bool get isWeb => false;