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 +1,183 @@
+import 'dart:convert';
+import 'package:http/http.dart' as http;
+import '../http_client.dart';
+import '../http_util.dart';
+import '../models.dart';
+import '../sse.dart';
+import 'webview_base_provider.dart';
+
+/// Duck.ai / DuckDuckGo chat. REST first; WebView executes the JS anti-bot hash.
+class DuckDuckGo extends WebViewBaseProvider {
+  @override
+  String get name => 'DuckDuckGo';
+
+  @override
+  bool get working => true;
+
+  @override
+  List<String> get models => [
+        'gpt-5.6-luna',
+        'gpt-5.4-mini',
+        'claude-haiku-4-5',
+        'mistralai/Mistral-Small-24B-Instruct-2501',
+        'meta-llama/Llama-4-Scout',
+      ];
+
+  @override
+  String get defaultModel => 'gpt-5.6-luna';
+
+  @override
+  String get baseUrl => 'https://duck.ai/';
+
+  @override
+  String get apiEndpoint => 'https://duckduckgo.com/duckchat/v1/chat';
+
+  static const _statusUrl = 'https://duckduckgo.com/duckchat/v1/status';
+  static const _chatUrl = 'https://duckduckgo.com/duckchat/v1/chat';
+
+  @override
+  Stream<String> createAsyncGenerator(
+    String model,
+    List<Message> messages, {
+    bool stream = false,
+  }) async* {
+    try {
+      await for (final chunk in _tryRest(model, messages, stream: stream)) {
+        yield chunk;
+      }
+      return;
+    } catch (_) {
+      // 418 challenge — fall through to a real browser context.
+    }
+    await for (final chunk in super.createAsyncGenerator(model, messages, stream: stream)) {
+      yield chunk;
+    }
+  }
+
+  Stream<String> _tryRest(
+    String model,
+    List<Message> messages, {
+    required bool stream,
+  }) async* {
+      final statusReq = http.Request('GET', Uri.parse(_statusUrl));
+      statusReq.headers.addAll(browserHeaders(
+        origin: 'https://duckduckgo.com',
+        referer: 'https://duckduckgo.com/',
+        accept: 'application/json',
+        extra: {'x-vqd-accept': '1'},
+      ));
+      final statusRes = await g4fHttp.send(statusReq).timeout(const Duration(seconds: 12));
+      final vqd4 = statusRes.headers['x-vqd-4'];
+      final hash1 = statusRes.headers['x-vqd-hash-1'];
+      await statusRes.stream.drain();
+      if (vqd4 == null || vqd4.isEmpty) {
+        throw Exception('DuckDuckGo: no x-vqd-4 (challenge required)');
+      }
+
+      final chatReq = http.Request('POST', Uri.parse(_chatUrl));
+      chatReq.headers.addAll(browserHeaders(
+        origin: 'https://duckduckgo.com',
+        referer: 'https://duckduckgo.com/',
+        contentType: 'application/json',
+        accept: 'text/event-stream',
+        extra: {
+          'x-vqd-4': vqd4,
+          if (hash1 != null && hash1.isNotEmpty) 'x-vqd-hash-1': hash1,
+        },
+      ));
+      chatReq.body = jsonEncode({
+        'model': models.contains(model) ? model : defaultModel,
+        'messages': toOpenAiMessages(messages),
+        'canUseTools': false,
+        'canUseApproxLocation': false,
+      });
+
+      final chatRes = await g4fHttp.send(chatReq).timeout(const Duration(seconds: 25));
+      if (chatRes.statusCode != 200) {
+        throw Exception('DuckDuckGo chat ${chatRes.statusCode}');
+      }
+
+      final collected = StringBuffer();
+      await for (final line in splitSseLines(chatRes.stream.transform(utf8.decoder))) {
+        final trimmed = line.trim();
+        if (trimmed.isEmpty || !trimmed.startsWith('data:')) continue;
+        final content = extractSseContent(trimmed.substring(5).trim());
+        if (content != null && content.isNotEmpty) {
+          collected.write(content);
+          if (stream) yield content;
+        }
+      }
+      final text = collected.toString();
+      if (!looksLikeModelOutput(text)) {
+        throw Exception('DuckDuckGo empty/challenge response');
+      }
+      if (!stream) yield text;
+  }
+
+  @override
+  String buildJsFetchCode(String model, List<Message> messages, bool stream) {
+    final messagesJson = jsonEncode(toOpenAiMessages(messages));
+    final modelJson = jsonEncode(models.contains(model) ? model : defaultModel);
+    return '''
+      (async function() {
+        const status = await fetch('https://duckduckgo.com/duckchat/v1/status', {
+          headers: { 'x-vqd-accept': '1', 'Accept': 'application/json' }
+        });
+        let vqd4 = status.headers.get('x-vqd-4') || '';
+        let hash1 = status.headers.get('x-vqd-hash-1') || '';
+        if (hash1) {
+          try {
+            let src = hash1;
+            try { src = atob(hash1); } catch (e) {}
+            if (src.includes('function') || src.trim().startsWith('(')) {
+              const result = await (0, eval)(src);
+              const value = (typeof result === 'function') ? await result() : result;
+              hash1 = btoa(JSON.stringify(value));
+            }
+          } catch (e) {
+            return JSON.stringify({error: 'hash failed: ' + e});
+          }
+        }
+        const headers = {
+          'Content-Type': 'application/json',
+          'Accept': 'text/event-stream'
+        };
+        if (vqd4) headers['x-vqd-4'] = vqd4;
+        if (hash1) headers['x-vqd-hash-1'] = hash1;
+        const resp = await fetch('https://duckduckgo.com/duckchat/v1/chat', {
+          method: 'POST',
+          headers,
+          body: JSON.stringify({
+            model: $modelJson,
+            messages: $messagesJson,
+            canUseTools: false,
+            canUseApproxLocation: false
+          })
+        });
+        const body = await resp.text();
+        return JSON.stringify({status: resp.status, body: body});
+      })();
+    ''';
+  }
+
+  @override
+  String parseResponse(String rawResponse) {
+    try {
+      final json = jsonDecode(rawResponse);
+      if (json is Map && json['error'] != null) {
+        throw Exception(json['error']);
+      }
+      final body = json is Map ? (json['body']?.toString() ?? rawResponse) : rawResponse;
+      final text = extractAllSseContent(body).join();
+      if (!looksLikeModelOutput(text)) {
+        throw Exception('DuckDuckGo WebView unusable: ${body.substring(0, body.length.clamp(0, 180))}');
+      }
+      return text;
+    } catch (e) {
+      if (e.toString().contains('DuckDuckGo')) rethrow;
+      final text = extractAllSseContent(rawResponse).join();
+      if (looksLikeModelOutput(text)) return text;
+      throw Exception('Failed to parse DuckDuckGo: $e');
+    }
+  }
+}