Refactor: use the same implement for total token count from res (#10197)

### What problem does this PR solve?
use the same implement for total token count from res

### Type of change

- [x] Refactoring

rag/llm/chat_model.py

@@ -36,7 +36,7 @@ from zhipuai import ZhipuAI
 
 from rag.llm import FACTORY_DEFAULT_BASE_URL, LITELLM_PROVIDER_PREFIX, SupportedLiteLLMProvider
 from rag.nlp import is_chinese, is_english
-from rag.utils import num_tokens_from_string
+from rag.utils import num_tokens_from_string, total_token_count_from_response
 
 
 # Error message constants
@@ -445,15 +445,7 @@ class Base(ABC):
         yield total_tokens
 
     def total_token_count(self, resp):
-        try:
-            return resp.usage.total_tokens
-        except Exception:
-            pass
-        try:
-            return resp["usage"]["total_tokens"]
-        except Exception:
-            pass
-        return 0
+       return total_token_count_from_response(resp)
 
     def _calculate_dynamic_ctx(self, history):
         """Calculate dynamic context window size"""

rag/llm/embedding_model.py

@@ -33,7 +33,7 @@ from zhipuai import ZhipuAI
 from api import settings
 from api.utils.file_utils import get_home_cache_dir
 from api.utils.log_utils import log_exception
-from rag.utils import num_tokens_from_string, truncate
+from rag.utils import num_tokens_from_string, truncate, total_token_count_from_response
 
 
 class Base(ABC):
@@ -52,15 +52,7 @@ class Base(ABC):
         raise NotImplementedError("Please implement encode method!")
 
     def total_token_count(self, resp):
-        try:
-            return resp.usage.total_tokens
-        except Exception:
-            pass
-        try:
-            return resp["usage"]["total_tokens"]
-        except Exception:
-            pass
-        return 0
+        return total_token_count_from_response(resp)
 
 
 class DefaultEmbedding(Base):

rag/llm/rerank_model.py

@@ -30,7 +30,7 @@ from yarl import URL
 from api import settings
 from api.utils.file_utils import get_home_cache_dir
 from api.utils.log_utils import log_exception
-from rag.utils import num_tokens_from_string, truncate
+from rag.utils import num_tokens_from_string, truncate, total_token_count_from_response
 
 class Base(ABC):
     def __init__(self, key, model_name, **kwargs):
@@ -44,18 +44,7 @@ class Base(ABC):
         raise NotImplementedError("Please implement encode method!")
 
     def total_token_count(self, resp):
-        if hasattr(resp, "usage") and hasattr(resp.usage, "total_tokens"):
-            try:
-                return resp.usage.total_tokens
-            except Exception:
-                pass
-
-        if 'usage' in resp and 'total_tokens' in resp['usage']:
-            try:
-                return resp["usage"]["total_tokens"]
-            except Exception:
-                pass
-        return 0
+        return total_token_count_from_response(resp)
 
 
 class DefaultRerank(Base):

rag/utils/__init__.py

@@ -88,6 +88,20 @@ def num_tokens_from_string(string: str) -> int:
     except Exception:
         return 0
 
+def total_token_count_from_response(resp):
+    if hasattr(resp, "usage") and hasattr(resp.usage, "total_tokens"):
+        try:
+            return resp.usage.total_tokens
+        except Exception:
+            pass
+
+    if 'usage' in resp and 'total_tokens' in resp['usage']:
+        try:
+            return resp["usage"]["total_tokens"]
+        except Exception:
+            pass
+    return 0
+
 
 def truncate(string: str, max_len: int) -> str:
     """Returns truncated text if the length of text exceed max_len."""