Fix: support cross language for API. (#8946)

### What problem does this PR solve?

Close #8943

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

api/apps/sdk/doc.py

@@ -38,7 +38,7 @@ from api.utils.api_utils import check_duplicate_ids, construct_json_result, get_
 from rag.app.qa import beAdoc, rmPrefix
 from rag.app.tag import label_question
 from rag.nlp import rag_tokenizer, search
-from rag.prompts import keyword_extraction
+from rag.prompts import keyword_extraction, cross_languages
 from rag.utils import rmSpace
 from rag.utils.storage_factory import STORAGE_IMPL
 
@@ -1382,6 +1382,7 @@ def retrieval_test(tenant_id):
     question = req["question"]
     doc_ids = req.get("document_ids", [])
     use_kg = req.get("use_kg", False)
+    langs = req.get("cross_languages", [])
     if not isinstance(doc_ids, list):
         return get_error_data_result("`documents` should be a list")
     doc_ids_list = KnowledgebaseService.list_documents_by_ids(kb_ids)
@@ -1406,6 +1407,9 @@ def retrieval_test(tenant_id):
         if req.get("rerank_id"):
             rerank_mdl = LLMBundle(kb.tenant_id, LLMType.RERANK, llm_name=req["rerank_id"])
 
+        if langs:
+            question = cross_languages(kb.tenant_id, None, question, langs)
+
         if req.get("keyword", False):
             chat_mdl = LLMBundle(kb.tenant_id, LLMType.CHAT)
             question += keyword_extraction(chat_mdl, question)