Fix: float transfer exception. (#6197)

### What problem does this PR solve?

#6177

### Type of change

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

rag/utils/__init__.py

@@ -19,6 +19,7 @@ import re
 import tiktoken
 from api.utils.file_utils import get_project_base_directory
 
+
 def singleton(cls, *args, **kw):
     instances = {}
 
@@ -89,3 +90,12 @@ def num_tokens_from_string(string: str) -> int:
 def truncate(string: str, max_len: int) -> str:
     """Returns truncated text if the length of text exceed max_len."""
     return encoder.decode(encoder.encode(string)[:max_len])
+
+
+def get_float(v: str | None):
+    if v is None:
+        return float('-inf')
+    try:
+        return float(v)
+    except Exception:
+        return float('-inf')

rag/utils/es_conn.py

@@ -26,7 +26,7 @@ from elasticsearch_dsl import UpdateByQuery, Q, Search, Index
 from elastic_transport import ConnectionTimeout
 from rag import settings
 from rag.settings import TAG_FLD, PAGERANK_FLD
-from rag.utils import singleton
+from rag.utils import singleton, get_float
 from api.utils.file_utils import get_project_base_directory
 from rag.utils.doc_store_conn import DocStoreConnection, MatchExpr, OrderByExpr, MatchTextExpr, MatchDenseExpr, \
     FusionExpr
@@ -178,7 +178,7 @@ class ESConnection(DocStoreConnection):
                                                                                                         MatchDenseExpr) and isinstance(
                     matchExprs[2], FusionExpr)
                 weights = m.fusion_params["weights"]
-                vector_similarity_weight = float(weights.split(",")[1])
+                vector_similarity_weight = get_float(weights.split(",")[1])
         for m in matchExprs:
             if isinstance(m, MatchTextExpr):
                 minimum_should_match = m.extra_options.get("minimum_should_match", 0.0)