Feat: Cross-Language Search for RAGFlow (#469)

* cross-language search

* test passed

src/rag/ragflow.py

@@ -4,6 +4,7 @@
 import os
 import requests
 from src.rag.retriever import Chunk, Document, Resource, Retriever
+from typing import List, Optional
 from urllib.parse import urlparse
 
 
@@ -15,6 +16,7 @@ class RAGFlowProvider(Retriever):
     api_url: str
     api_key: str
     page_size: int = 10
+    cross_languages: Optional[List[str]] = None
 
     def __init__(self):
         api_url = os.getenv("RAGFLOW_API_URL")
@@ -31,6 +33,11 @@ class RAGFlowProvider(Retriever):
         if page_size:
             self.page_size = int(page_size)
 
+        self.cross_languages = None
+        cross_languages = os.getenv("RAGFLOW_CROSS_LANGUAGES")
+        if cross_languages:
+            self.cross_languages = cross_languages.split(",")
+
     def query_relevant_documents(
         self, query: str, resources: list[Resource] = []
     ) -> list[Document]:
@@ -55,6 +62,9 @@ class RAGFlowProvider(Retriever):
             "page_size": self.page_size,
         }
 
+        if self.cross_languages:
+            payload["cross_languages"] = self.cross_languages
+
         response = requests.post(
             f"{self.api_url}/api/v1/retrieval", headers=headers, json=payload
         )