fix bug about fetching file from minio (#574)

### What problem does this PR solve?


### Type of change

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

api/db/services/file2document_service.py

@@ -18,6 +18,8 @@ from datetime import datetime
 from api.db.db_models import DB
 from api.db.db_models import File, Document, File2Document
 from api.db.services.common_service import CommonService
+from api.db.services.document_service import DocumentService
+from api.db.services.file_service import FileService
 from api.utils import current_timestamp, datetime_format
 
 
@@ -64,3 +66,18 @@ class File2DocumentService(CommonService):
         num = cls.model.update(obj).where(cls.model.id == file_id).execute()
         e, obj = cls.get_by_id(cls.model.id)
         return obj
+
+    @classmethod
+    @DB.connection_context()
+    def get_minio_address(cls, doc_id=None, file_id=None):
+        if doc_id:
+            ids = File2DocumentService.get_by_document_id(doc_id)
+        else:
+            ids = File2DocumentService.get_by_file_id(file_id)
+        if ids:
+            e, file = FileService.get_by_id(ids[0].file_id)
+            return file.parent_id, file.location
+        else:
+            assert doc_id, "please specify doc_id"
+            e, doc = DocumentService.get_by_id(doc_id)
+            return doc.kb_id, doc.location