fix(search): fix DDGS Wikipedia region handling (#3423)

backend/packages/harness/deerflow/community/ddg_search/tools.py

@@ -11,12 +11,85 @@ from deerflow.config import get_app_config
 
 logger = logging.getLogger(__name__)
 
+DEFAULT_BACKEND = "auto"
+DEFAULT_REGION = "wt-wt"
+DEFAULT_SAFESEARCH = "moderate"
+DEFAULT_WIKIPEDIA_REGION = "us-en"
+
+WIKIPEDIA_BACKENDS = {"auto", "all", "wikipedia"}
+WIKIPEDIA_LANGUAGE_ALIASES = {
+    "jp": "ja",
+    "kr": "ko",
+    "tzh": "zh",
+    "wt": "en",
+}
+
+
+def _normalize_backend(backend: str | list[str] | tuple[str, ...] | None) -> str:
+    if backend is None:
+        return DEFAULT_BACKEND
+    if isinstance(backend, (list, tuple)):
+        return ",".join(str(part).strip() for part in backend if str(part).strip()) or DEFAULT_BACKEND
+    return str(backend).strip() or DEFAULT_BACKEND
+
+
+def _normalize_setting(value: str | None, default: str) -> str:
+    return str(value).strip() if value else default
+
+
+def _backend_includes_wikipedia(backend: str | list[str] | tuple[str, ...] | None) -> bool:
+    backend = _normalize_backend(backend)
+    return any(part.strip().lower() in WIKIPEDIA_BACKENDS for part in backend.split(","))
+
+
+def _contains_codepoint(query: str, ranges: tuple[tuple[int, int], ...]) -> bool:
+    return any(start <= ord(char) <= end for char in query for start, end in ranges)
+
+
+def _infer_wikipedia_region(query: str) -> str:
+    """Pick a valid Wikipedia language region when DDGS' worldwide region is used."""
+    if _contains_codepoint(query, ((0x3040, 0x30FF), (0x31F0, 0x31FF))):
+        return "jp-ja"
+    if _contains_codepoint(query, ((0xAC00, 0xD7AF), (0x1100, 0x11FF), (0x3130, 0x318F))):
+        return "kr-ko"
+    if _contains_codepoint(query, ((0x3400, 0x9FFF),)):
+        return "cn-zh"
+    if _contains_codepoint(query, ((0x0400, 0x04FF),)):
+        return "ru-ru"
+    if _contains_codepoint(query, ((0x0370, 0x03FF),)):
+        return "gr-el"
+    if _contains_codepoint(query, ((0x0590, 0x05FF),)):
+        return "il-he"
+    if _contains_codepoint(query, ((0x0600, 0x06FF),)):
+        return "xa-ar"
+    return DEFAULT_WIKIPEDIA_REGION
+
+
+def _resolve_ddgs_region(query: str, region: str | None, backend: str | list[str] | tuple[str, ...] | None) -> str:
+    """
+    DDGS' wikipedia engine treats the second part of region as a Wikipedia
+    subdomain. Its default worldwide region, wt-wt, becomes wt.wikipedia.org.
+    """
+    normalized_region = _normalize_setting(region, DEFAULT_REGION).lower()
+    if not _backend_includes_wikipedia(backend):
+        return normalized_region
+
+    if normalized_region == DEFAULT_REGION:
+        return _infer_wikipedia_region(query)
+
+    if "-" not in normalized_region:
+        return DEFAULT_WIKIPEDIA_REGION
+
+    country, language = normalized_region.split("-", 1)
+    return f"{country}-{WIKIPEDIA_LANGUAGE_ALIASES.get(language, language)}"
+
 
 def _search_text(
     query: str,
     max_results: int = 5,
-    region: str = "wt-wt",
-    safesearch: str = "moderate",
+    region: str | None = DEFAULT_REGION,
+    safesearch: str | None = DEFAULT_SAFESEARCH,
+    backend: str | list[str] | tuple[str, ...] | None = DEFAULT_BACKEND,
 ) -> list[dict]:
     """
     Execute text search using DuckDuckGo.
@@ -26,6 +99,7 @@ def _search_text(
         max_results: Maximum number of results
         region: Search region
         safesearch: Safe search level
+        backend: DDGS backend(s), e.g. "auto", "duckduckgo", or "duckduckgo,brave"
 
     Returns:
         List of search results
@@ -39,11 +113,15 @@ def _search_text(
     ddgs = DDGS(timeout=30)
 
     try:
+        backend = _normalize_backend(backend)
+        safesearch = _normalize_setting(safesearch, DEFAULT_SAFESEARCH)
+        effective_region = _resolve_ddgs_region(query, region, backend)
         results = ddgs.text(
             query,
-            region=region,
+            region=effective_region,
             safesearch=safesearch,
             max_results=max_results,
+            backend=backend,
         )
         return list(results) if results else []
 
@@ -64,14 +142,23 @@ def web_search_tool(
         max_results: Maximum number of results to return. Default is 5.
     """
     config = get_app_config().get_tool_config("web_search")
+    region = DEFAULT_REGION
+    safesearch = DEFAULT_SAFESEARCH
+    backend = DEFAULT_BACKEND
 
-    # Override max_results from config if set
-    if config is not None and "max_results" in config.model_extra:
+    if config is not None:
+        # Override tool call defaults from config if set.
         max_results = config.model_extra.get("max_results", max_results)
+        region = config.model_extra.get("region", region)
+        safesearch = config.model_extra.get("safesearch", safesearch)
+        backend = config.model_extra.get("backend", backend)
 
     results = _search_text(
         query=query,
         max_results=max_results,
+        region=region,
+        safesearch=safesearch,
+        backend=backend,
     )
 
     if not results:

backend/tests/test_ddg_search_tools.py

@@ -0,0 +1,75 @@
+"""Unit tests for the DDGS community web search tool."""
+
+import json
+import sys
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+from deerflow.community.ddg_search import tools
+
+
+def test_resolve_ddgs_region_maps_worldwide_chinese_query_for_wikipedia() -> None:
+    assert tools._resolve_ddgs_region("\u4e16\u754c\u676f\u65b0\u95fb 2026", "wt-wt", "auto") == "cn-zh"
+
+
+def test_resolve_ddgs_region_uses_english_fallback_for_worldwide_query() -> None:
+    assert tools._resolve_ddgs_region("latest world cup news", "wt-wt", "auto") == "us-en"
+
+
+def test_resolve_ddgs_region_preserves_worldwide_for_non_wikipedia_backend() -> None:
+    assert tools._resolve_ddgs_region("latest world cup news", "wt-wt", "duckduckgo") == "wt-wt"
+
+
+def test_resolve_ddgs_region_maps_common_ddg_locale_aliases() -> None:
+    assert tools._resolve_ddgs_region("\u65e5\u672c \u30cb\u30e5\u30fc\u30b9", "jp-jp", "auto") == "jp-ja"
+    assert tools._resolve_ddgs_region("\ud55c\uad6d \ub274\uc2a4", "kr-kr", "auto") == "kr-ko"
+    assert tools._resolve_ddgs_region("\u53f0\u7063\u65b0\u805e", "tw-tzh", "auto") == "tw-zh"
+
+
+def test_search_text_passes_wikipedia_safe_region_to_ddgs(monkeypatch) -> None:
+    calls = {}
+
+    class FakeDDGS:
+        def __init__(self, timeout: int) -> None:
+            calls["timeout"] = timeout
+
+        def text(self, query: str, **kwargs):
+            calls["query"] = query
+            calls.update(kwargs)
+            return [{"title": "Result", "href": "https://example.com", "body": "Snippet"}]
+
+    monkeypatch.setitem(sys.modules, "ddgs", SimpleNamespace(DDGS=FakeDDGS))
+
+    results = tools._search_text("\u4e16\u754c\u676f\u65b0\u95fb 2026", backend="auto")
+
+    assert results == [{"title": "Result", "href": "https://example.com", "body": "Snippet"}]
+    assert calls["timeout"] == 30
+    assert calls["region"] == "cn-zh"
+    assert calls["backend"] == "auto"
+
+
+def test_web_search_tool_reads_ddgs_options_from_config() -> None:
+    with patch("deerflow.community.ddg_search.tools.get_app_config") as mock_config:
+        tool_config = MagicMock()
+        tool_config.model_extra = {
+            "max_results": 3,
+            "region": "us-en",
+            "safesearch": "off",
+            "backend": "auto",
+        }
+        mock_config.return_value.get_tool_config.return_value = tool_config
+
+        with patch("deerflow.community.ddg_search.tools._search_text") as mock_search:
+            mock_search.return_value = [{"title": "Result", "href": "https://example.com", "body": "Snippet"}]
+
+            result = tools.web_search_tool.invoke({"query": "latest news", "max_results": 8})
+            parsed = json.loads(result)
+
+    assert parsed["total_results"] == 1
+    mock_search.assert_called_once_with(
+        query="latest news",
+        max_results=3,
+        region="us-en",
+        safesearch="off",
+        backend="auto",
+    )

config.example.yaml

@@ -436,6 +436,9 @@ tools:
     group: web
     use: deerflow.community.ddg_search.tools:web_search_tool
     max_results: 5
+    # backend: auto          # DDGS backend(s): auto, duckduckgo, brave, wikipedia, etc.
+    # region: wt-wt          # wt-wt is normalized for Wikipedia when backend includes auto/all/wikipedia.
+    # safesearch: moderate   # on, moderate, off
 
   # Web search tool (uses Serper - Google Search API, requires SERPER_API_KEY)
   # Serper provides real-time Google Search results. Sign up at https://serper.dev