feat: embed a Flutter G4F client with Cronet, cookie jar, and origin WebView

Port the Oracle off the Python g4f container onto on-device providers: Chromium HTTP via Cronet, a shared cookie session, IterList retry, hosted OpenAI-compat aggregators, and same-origin WebView fallbacks instead of CORS fetch.
2026-09-01 22:05:38 +05:00
parent f3e7412cf9
commit fbf04d90db
49 changed files with 4856 additions and 92 deletions
@@ -0,0 +1,83 @@
+import 'dart:io';
+
+import 'package:cronet_http/cronet_http.dart';
+import 'package:flutter/foundation.dart';
+import 'package:http/http.dart' as http;
+
+import 'cookie_jar.dart';
+import 'http_util.dart';
+
+/// Shared HTTP stack for every G4F provider.
+///
+/// Python g4f uses `curl_cffi(impersonate="chrome")` plus a session cookie
+/// jar. On Android the closest TLS equivalent is Cronet; cookies are kept
+/// in [g4fCookies] because Cronet does not expose a Dart cookie store.
+http.Client createG4fClient() {
+  if (!kIsWeb && Platform.isAndroid) {
+    final engine = CronetEngine.build(
+      cacheMode: CacheMode.memory,
+      cacheMaxSize: 4 * 1024 * 1024,
+      userAgent: kDesktopUserAgent,
+      enableHttp2: true,
+      enableBrotli: true,
+      enableQuic: true,
+    );
+    return CronetClient.fromCronetEngine(engine);
+  }
+  return http.Client();
+}
+
+final G4fCookieJar g4fCookies = G4fCookieJar();
+
+final http.Client g4fHttp = CookieClient(createG4fClient(), g4fCookies);
+
+class CookieClient extends http.BaseClient {
+  CookieClient(this._inner, this.jar);
+
+  final http.Client _inner;
+  final G4fCookieJar jar;
+
+  @override
+  Future<http.StreamedResponse> send(http.BaseRequest request) async {
+    final fromJar = jar.headerFor(request.url);
+    if (fromJar.isNotEmpty) {
+      final existing = request.headers['cookie'];
+      if (existing == null || existing.isEmpty) {
+        request.headers['cookie'] = fromJar;
+      } else {
+        request.headers['cookie'] = '$existing; $fromJar';
+      }
+    }
+    final response = await _inner.send(request);
+    jar.absorb(request.url, response.headers);
+    return response;
+  }
+
+  @override
+  void close() => _inner.close();
+}
+
+final Set<String> _warmedOrigins = {};
+
+/// GET the provider origin once so Cloudflare/session cookies land in [g4fCookies].
+Future<void> warmupOrigin(String url) async {
+  if (url.isEmpty) return;
+  final uri = Uri.tryParse(url);
+  if (uri == null || !uri.hasScheme || uri.host.isEmpty) return;
+  final origin = uri.origin;
+  if (_warmedOrigins.contains(origin)) return;
+  _warmedOrigins.add(origin);
+  try {
+    await g4fHttp
+        .get(
+          uri,
+          headers: browserHeaders(
+            desktop: true,
+            accept:
+                'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
+            referer: '$origin/',
+          ),
+        )
+        .timeout(const Duration(seconds: 12));
+  } catch (_) {}
+}