feat: add ability to cancel in-flight HTTP requests and manage client lifecycle

packages/apidash_core/lib/services/client_manager.dart

@@ -0,0 +1,33 @@
+import 'package:http/http.dart' as http;
+
+class HttpClientManager {
+  static final HttpClientManager _instance = HttpClientManager._internal();
+  final Map<String, http.Client> _clients = {};
+
+  factory HttpClientManager() {
+    return _instance;
+  }
+
+  HttpClientManager._internal();
+
+  http.Client createClient(String requestId) {
+    final client = http.Client();
+    _clients[requestId] = client;
+    return client;
+  }
+
+  void cancelRequest(String requestId) {
+    if (_clients.containsKey(requestId)) {
+      _clients[requestId]?.close();
+      _clients.remove(requestId);
+    }
+  }
+
+  void closeClient(String requestId) {
+    cancelRequest(requestId);
+  }
+
+  bool hasActiveClient(String requestId) {
+    return _clients.containsKey(requestId);
+  }
+}

packages/apidash_core/lib/services/http_service.dart

@@ -6,14 +6,22 @@ import 'package:seed/seed.dart';
 import '../consts.dart';
 import '../models/models.dart';
 import '../utils/utils.dart';
+import 'client_manager.dart';
 
 typedef HttpResponse = http.Response;
 
 Future<(HttpResponse?, Duration?, String?)> request(
   HttpRequestModel requestModel, {
   String defaultUriScheme = kDefaultUriScheme,
-  http.Client? client,
+  String? requestId,
 }) async {
+  final clientManager = HttpClientManager();
+  http.Client? client;
+
+  if (requestId != null) {
+    client = clientManager.createClient(requestId);
+  }
+
   (Uri?, String?) uriRec = getValidRequestUri(
     requestModel.url,
     requestModel.enabledParams,
@@ -110,6 +118,9 @@ Future<(HttpResponse?, Duration?, String?)> request(
       if (shouldCloseClient) {
         client?.close();
       }
+      if (requestId != null) {
+        clientManager.closeClient(requestId);
+      }
     }
   } else {
     return (null, null, uriRec.$2);

packages/apidash_core/lib/services/services.dart

@@ -1 +1,2 @@
 export 'http_service.dart';
+export 'client_manager.dart';