refactor: adjust model check, tool calls, and response handling logic

- Updated `thinking_enabled` condition in `DeepSeekAPI.py` to ensure `model` is not None before checking substring
- Removed default `tool_calls` value in `/backend-api/v2/create` route in `backend_api.py`
- Simplified response caching logic by consolidating `cast_str` handling and ensuring `response` is a string before writing
- Adjusted response filtering logic to handle string vs iterable cases more consistently
- Refined safe search tag check in file matching loop to only test the first tag against MIME type in `backend_api.py`
- Changed default filename from "index" to "home" in `_index` method of `website.py

g4f/Provider/needs_auth/DeepSeekAPI.py

@@ -67,7 +67,7 @@ class DeepSeekAPI(AsyncAuthedProvider, ProviderModelMixin):
         for chunk in api.chat_completion(
             conversation.chat_id,
             get_last_user_message(messages),
-            thinking_enabled="deepseek-r1" in model,
+            thinking_enabled=bool(model) and "deepseek-r1" in model,
             search_enabled=web_search
         ):
             if chunk['type'] == 'thinking':

g4f/gui/server/backend_api.py

@@ -210,12 +210,7 @@ class Backend_Api(Api):
         @app.route('/backend-api/v2/create', methods=['GET', 'POST'])
         def create():
             try:
-                tool_calls = [{
-                    "function": {
-                        "name": "bucket_tool"
-                    },
-                    "type": "function"
-                }]
+                tool_calls = []
                 web_search = request.args.get("web_search")
                 if web_search:
                     is_true_web_search = web_search.lower() in ["true", "1"]
@@ -277,12 +272,11 @@ class Backend_Api(Api):
                     if not response:
                         response = iter_run_tools(ChatCompletion.create, **parameters)
                         cache_dir.mkdir(parents=True, exist_ok=True)
-                        copy_response = cast_str(response)
-                        if copy_response:
+                        response = cast_str(response)
+                        response = response if isinstance(response, str) else "".join(response)
+                        if response:
                             with cache_file.open("w") as f:
-                                for chunk in [copy_response] if isinstance(copy_response, str) else copy_response:
-                                    f.write(chunk)
-                        response = copy_response
+                                f.write(response)
                 else:
                     response = cast_str(iter_run_tools(ChatCompletion.create, **parameters))
                 if isinstance(response, str):
@@ -298,7 +292,7 @@ class Backend_Api(Api):
                         return redirect(response)
                 if do_filter:
                     is_true_filter = do_filter.lower() in ["true", "1"]
-                    response = "".join(response)
+                    response = response if isinstance(response, str) else "".join(response)
                     return Response(filter_markdown(response, None if is_true_filter else do_filter, response if is_true_filter else ""), mimetype='text/plain')
                 return Response(response, mimetype='text/plain')
             except Exception as e:
@@ -412,8 +406,7 @@ class Backend_Api(Api):
                         mime_type = is_allowed_extension(file)
                         if mime_type is not None:
                             mime_type = secure_filename(mime_type)
-                            for tag in safe_search:
-                                if tag in mime_type:
+                            if safe_search[0] in mime_type:
                                 self.match_files[search][file] = self.match_files[search].get(file, 0) + 1
                                 break
                         for tag in safe_search:

g4f/gui/server/website.py

@@ -67,7 +67,7 @@ class Website:
             },
         }
 
-    def _index(self, filename = "index"):
+    def _index(self, filename = "home"):
         return render(filename)
 
     def _qrcode(self, filename = "qrcode"):